Release v1.19.6

* Allow directory listings to be pre-computed
* Do not require struct modules to be loaded

The current implementation would require us to
recompute protocols whenever a struct changed,
something that is not currently available.
Furthermore, the fact we had to load modules
naturally made consolidation more expensive.
Therefore we need a lazy type resolution,
and until we have such feature, we will only
track struct names.

CHANGELOG.md

@@ -234,6 +234,94 @@ These additions offer greater transparency into the components and licenses of e
 
 This work was performed by [Jonatan Männchen](https://maennchen.dev) and sponsored by the [Erlang Ecosystem Foundation](https://erlef.org).
 
+## v1.19.6 (2026-08-28)
+
+### 1. Security
+
+  * [List] Avoid recursion when invalid charlists are given to `List.to_string/1` or `List.to_charlist/1` (CVE-2026-75758, GHSA-jf5q-v438-665c)
+
+## v1.19.5 (2026-01-09)
+
+### 1. Enhancements
+
+#### Elixir
+
+  * [Protocol] Optimize protocol consolidation to no longer load structs
+
+### 2. Bug fixes
+
+#### Elixir
+
+  * [Kernel] Fix unnecessary recompilation when `dbg_callback` is modified at runtime
+  * [Kernel] Fix parser crash on missing parentheses on expression following operator `not in`
+  * [Kernel] Support fetching abstract code for modules compiled with Elixir v1.14 and earlier
+  * [Protocol] Ensure protocol consolidation no longer stores outdated struct types. As a consequence, protocols types only track struct names at the moment
+  * [Stream] Revert optimization which caused nested streams in `Stream.flat_map/2` to crash
+
+#### IEx
+
+  * [IEx] Fix usage of `#iex:break` as part of multi-line prompts
+
+#### Logger
+
+  * [Logger.Backends] Do not crash on invalid metadata
+
+## v1.19.4 (2025-11-27)
+
+### 1. Enhancements
+
+#### Mix
+
+  * [mix xref] Add `--min-cycle-label` to help projects adapt to the more precise `mix xref graph` reports in Elixir v1.19. In previous versions, Elixir would break a large compilation cycle into several smaller ones, and therefore developers would check for `--min-cycle-size` on CI. However, the issue is not the size of the cycle (it has no implication in the amount of compiled files), but how many compile-time dependencies (aka compile labels) in a cycle. The new option allows developers to filter on the label parameter
+
+### 2. Bug fixes
+
+#### Elixir
+
+  * [File] Ensure `File.cp_r/3` reports non-existing destination properly (instead of source)
+
+#### ExUnit
+
+  * [ExUnit] Fix formatter crash when diffing takes too long
+  * [ExUnit] Ensure parallel matches in `assert` propagate type information
+
+#### Logger
+
+  * [Logger] Fix regression where formatter would crash when given chardata (the crash would happen when logging non-ASCII characters)
+
+#### Mix
+
+  * [mix help] Ensure `app:APP` works when the project or its dependencies were not yet compiled
+  * [mix escript.build] Ensure the `hex` application can be included in escripts
+
+## v1.19.3 (2025-11-13)
+
+### 1. Enhancements
+
+#### Elixir
+
+  * [Kernel] Support /E modifier for regular expressions in config files
+
+#### Mix
+
+  * [mix compile] Allow forcing specific compilers, such as `--force-elixir`, `--force-app`, etc
+  * [mix help app:APP] Support showing helps for apps in Elixir and Erlang standard libraries
+
+### 2. Bug fixes
+
+#### Elixir
+
+  * [IO] Fix dialyzer warning on `IO.inspect :label`
+
+#### ExUnit
+
+  * [ExUnit.Case] Fix crash when formatting errors caused by a linked/trapped exit during `setup_all`
+
+#### Mix
+
+  * [mix compile.app] Ensure functions in the format `&Mod.fun/arity` can be written to .app files
+  * [mix compile.app] Ensure strings with Unicode characters can be written to .app files
+
 ## v1.19.2 (2025-11-02)
 
 ### 1. Enhancements

VERSION

@@ -1 +1 @@
-1.19.2
+1.19.6

bin/elixir

@@ -6,7 +6,7 @@
 
 set -e
 
-ELIXIR_VERSION=1.19.2
+ELIXIR_VERSION=1.19.6
 
 if [ $# -eq 0 ] || { [ $# -eq 1 ] && { [ "$1" = "--help" ] || [ "$1" = "-h" ]; }; }; then
   cat <<USAGE >&2

bin/elixir.bat

@@ -4,7 +4,7 @@
 :: SPDX-FileCopyrightText: 2021 The Elixir Team
 :: SPDX-FileCopyrightText: 2012 Plataformatec
 
-set ELIXIR_VERSION=1.19.2
+set ELIXIR_VERSION=1.19.6
 
 if    ""%1""==""""                if ""%2""=="""" goto documentation
 if /I ""%1""==""--help""          if ""%2""=="""" goto documentation

lib/elixir/lib/code.ex

@@ -1090,7 +1090,7 @@ defmodule Code do
   @doc since: "1.6.0"
   @spec format_string!(binary, [format_opt]) :: iodata
   def format_string!(string, opts \\ []) when is_binary(string) and is_list(opts) do
-    line_length = Keyword.get(opts, :line_length, 98)
+    {line_length, opts} = Keyword.pop(opts, :line_length, 98)
 
     to_quoted_opts =
       [

lib/elixir/lib/file.ex

@@ -1224,7 +1224,13 @@ defmodule File do
   defp do_cp_r(src, dest, on_conflict, dereference?, acc) when is_list(acc) do
     case :elixir_utils.read_link_type(src) do
       {:ok, :regular} ->
-        do_cp_file(src, dest, on_conflict, acc)
+        case do_cp_file(src, dest, on_conflict, acc) do
+          # we don't have a way to make a distinction between a non-existing src
+          # or dest being a non-existing dir in the case of :enoent,
+          # but we already know that src exists here.
+          {:error, :enoent, _} -> {:error, :enoent, dest}
+          other -> other
+        end
 
       {:ok, :symlink} ->
         case :file.read_link(src) do

lib/elixir/lib/inspect.ex

@@ -389,13 +389,20 @@ defimpl Inspect, for: List do
     close = color_doc("]", :list, opts)
 
     cond do
-      lists == :as_charlists or (lists == :infer and List.ascii_printable?(term, printable_limit)) ->
-        inspected =
-          case Identifier.escape(IO.chardata_to_string(term), ?", printable_limit) do
-            {escaped, ""} -> [?~, ?c, ?", escaped, ?"]
-            {escaped, _} -> [?~, ?c, ?", escaped, ?", " ++ ..."]
+      (lists == :as_charlists and unicode_list?(term, printable_limit)) or
+          (lists == :infer and List.ascii_printable?(term, printable_limit)) ->
+        {split, tail} =
+          if is_integer(printable_limit) do
+            case Enum.split(term, printable_limit) do
+              {split, []} -> {split, []}
+              {split, _} -> {split, " ++ ..."}
+            end
+          else
+            {term, []}
           end
 
+        {escaped, _} = Identifier.escape(IO.chardata_to_string(split), ?")
+        inspected = [?~, ?c, ?", escaped, ?" | tail]
         color_doc(IO.iodata_to_binary(inspected), :charlist, opts)
 
       keyword?(term) ->
@@ -409,6 +416,19 @@ defimpl Inspect, for: List do
     end
   end
 
+  defp unicode_list?(_, 0), do: true
+
+  defp unicode_list?([char | rest], counter)
+       when char in 0..0xD7FF or char in 0xE000..0x10FFFF,
+       do: unicode_list?(rest, decrement(counter))
+
+  defp unicode_list?([], _counter), do: true
+  defp unicode_list?(_, _counter), do: false
+
+  @compile {:inline, decrement: 1}
+  defp decrement(:infinity), do: :infinity
+  defp decrement(counter), do: counter - 1
+
   @doc false
   def keyword({key, value}, opts) do
     key = color_doc(Macro.inspect_atom(:key, key), :atom, opts)
@@ -569,6 +589,7 @@ defimpl Inspect, for: Regex do
   defp translate_options([:firstline | t], acc), do: translate_options(t, [?f | acc])
   defp translate_options([:ungreedy | t], acc), do: translate_options(t, [?U | acc])
   defp translate_options([:multiline | t], acc), do: translate_options(t, [?m | acc])
+  defp translate_options([:export | t], acc), do: translate_options(t, [?E | acc])
   defp translate_options([], acc), do: acc
   defp translate_options(_t, _acc), do: :error
 

lib/elixir/lib/inspect/algebra.ex

@@ -21,8 +21,8 @@ defmodule Inspect.Opts do
       is `:decimal` and if it is printable, otherwise in bit syntax. See
       `String.printable?/1` to learn when a string is printable.
 
-    * `:charlists` - when `:as_charlists` all lists will be printed as charlists,
-      non-printable elements will be escaped.
+    * `:charlists` - when `:as_charlists` all charlists will be printed as charlists,
+      non-printable code points will be escaped. Other lists will be printed as lists.
 
       When `:as_lists` all lists will be printed as lists.
 

lib/elixir/lib/list.ex

@@ -1137,7 +1137,7 @@ defmodule List do
 
         Please check the given list or call inspect/1 to get the list representation, got:
 
-        #{inspect(list)}
+        #{inspect(list, charlists: :as_lists)}
         """
     else
       result when is_binary(result) ->
@@ -1189,7 +1189,7 @@ defmodule List do
 
         Please check the given list or call inspect/1 to get the list representation, got:
 
-        #{inspect(list)}
+        #{inspect(list, charlists: :as_lists)}
         """
     else
       result when is_list(result) ->

lib/elixir/lib/macro.ex

@@ -959,8 +959,9 @@ defmodule Macro do
   backwards compatibility purposes.
 
   In future releases, Elixir may introduce truly required struct
-  fields, and therefore only one of required or default will be
-  present. Your code should prepare for such scenario accordingly.
+  fields, the required field will be removed and default will be
+  present only if the field is optional. Your code should prepare
+  for such scenario accordingly.
   """
   @doc since: "1.18.0"
   @spec struct_info!(module(), Macro.Env.t()) ::

lib/elixir/lib/module.ex

@@ -402,30 +402,21 @@ defmodule Module do
 
   Accepts the function name (as an atom) of a function in the current module.
   The function must have an arity of 0 (no arguments). If the function does
-  not return `:ok`, the loading of the module will be aborted.
-  For example:
+  not return `:ok`, the loading of the module will be aborted. Its primary
+  use case is to load [NIFs](https://www.erlang.org/doc/man/erl_nif):
 
       defmodule MyModule do
-        @on_load :load_check
+        @on_load :load_external_code
 
-        def load_check do
-          if some_condition() do
-            :ok
-          else
-            :abort
-          end
-        end
-
-        def some_condition do
-          false
+        def load_external_code do
+          :erlang.load_nif(~c"path/to/extension.so_or_dll")
         end
       end
 
   The function given to `on_load` should avoid calling functions from
-  other modules. If you must call functions in other modules and those
-  modules are defined within the same project, the called modules must
-  have the `@compile {:autoload, true}` annotation, so they are loaded
-  upfront (and not from within the `@on_load` callback).
+  other modules. This is because, when running a `mix release`,
+  `on_load` runs extremely early, before any application starts running,
+  and therefore even systems like the `Logger` and `IO` are not yet available.
 
   ### `@vsn`
 

lib/elixir/lib/module/types/apply.ex

@@ -1067,6 +1067,17 @@ defmodule Module.Types.Apply do
                   """
               end
 
+            # The protocol has, at the moment, simplified clauses, so we build the complete one
+            clauses =
+              case mod.__protocol__(:impls) do
+                {:consolidated, mods} ->
+                  domain = mods |> Enum.map(&Module.Types.Of.impl/1) |> Enum.reduce(&union/2)
+                  [{[domain], dynamic()}]
+
+                _ ->
+                  clauses
+              end
+
             {"""
              but expected a type that implements the #{inspect(mod)} protocol.
              #{fix}\

lib/elixir/lib/module/types/of.ex

@@ -141,14 +141,25 @@ defmodule Module.Types.Of do
     {Any, term()}
   ]
 
+  @doc """
+  Currently, for protocol implementations, we only store
+  the open struct definition. This is because we don't want
+  to reconsolidate whenever the struct changes, but at the
+  moment we can't store references either. Ideally struct
+  types on protocol dispatches would be lazily resolved.
+  """
+  def impl(for, mode \\ :closed)
+
   for {for, type} <- impls do
-    def impl(unquote(for)), do: unquote(Macro.escape(type))
+    def impl(unquote(for), _mode), do: unquote(Macro.escape(type))
   end
 
-  def impl(struct) do
-    # Elixir did not strictly require the implementation to be available, so we need a fallback.
+  def impl(struct, mode) do
+    # Elixir did not strictly require the implementation to be available,
+    # so we need to deal with such cases accordingly.
     # TODO: Assume implementation is available on Elixir v2.0.
-    if info = Code.ensure_loaded?(struct) && struct.__info__(:struct) do
+    # A warning is emitted since v1.19+.
+    if info = mode == :closed && Code.ensure_loaded?(struct) && struct.__info__(:struct) do
       struct_type(struct, info)
     else
       open_map(__struct__: atom([struct]))

lib/elixir/lib/protocol.ex

@@ -453,7 +453,7 @@ defmodule Protocol do
       true
 
   """
-  @spec extract_protocols([charlist | String.t()]) :: [atom]
+  @spec extract_protocols([charlist | String.t() | {charlist, [charlist]}]) :: [atom]
   def extract_protocols(paths) do
     extract_matching_by_attribute(paths, [?E, ?l, ?i, ?x, ?i, ?r, ?.], fn module, attributes ->
       case attributes[:__protocol__] do
@@ -482,7 +482,7 @@ defmodule Protocol do
       true
 
   """
-  @spec extract_impls(module, [charlist | String.t()]) :: [atom]
+  @spec extract_impls(module, [charlist | String.t() | {charlist, [charlist]}]) :: [atom]
   def extract_impls(protocol, paths) when is_atom(protocol) do
     prefix = Atom.to_charlist(protocol) ++ [?.]
 
@@ -496,17 +496,25 @@ defmodule Protocol do
 
   defp extract_matching_by_attribute(paths, prefix, callback) do
     for path <- paths,
-        # Do not use protocols as they may be consolidating
-        path = if(is_list(path), do: path, else: String.to_charlist(path)),
-        file <- list_dir(path),
+        {path, files} = list_dir(path),
+        file <- files,
         mod = extract_from_file(path, file, prefix, callback),
         do: mod
   end
 
+  # Do not use protocols as they may be consolidating
+  defp list_dir({path, files}) when is_list(path) and is_list(files) do
+    {path, files}
+  end
+
+  defp list_dir(path) when is_binary(path) do
+    list_dir(String.to_charlist(path))
+  end
+
   defp list_dir(path) when is_list(path) do
     case :file.list_dir(path) do
-      {:ok, files} -> files
-      _ -> []
+      {:ok, files} -> {path, files}
+      _ -> {path, []}
     end
   end
 
@@ -633,7 +641,7 @@ defmodule Protocol do
         checker =
           if checker do
             update_in(checker.exports, fn exports ->
-              signatures = new_signatures(definitions, protocol_funs, protocol, types)
+              signatures = new_signatures(definitions, protocol_funs, protocol, types, structs)
 
               for {fun, info} <- exports do
                 if sig = Map.get(signatures, fun) do
@@ -652,14 +660,13 @@ defmodule Protocol do
     end
   end
 
-  defp new_signatures(definitions, protocol_funs, protocol, types) do
+  defp new_signatures(definitions, protocol_funs, protocol, types, structs) do
     alias Module.Types.Descr
+    types_minus_any = List.delete(types, Any)
 
     clauses =
-      types
-      |> List.delete(Any)
-      |> Enum.map(fn impl ->
-        {[Module.Types.Of.impl(impl)], Descr.atom([__concat__(protocol, impl)])}
+      Enum.map(types_minus_any, fn impl ->
+        {[Module.Types.Of.impl(impl, :open)], Descr.atom([__concat__(protocol, impl)])}
       end)
 
     {domain, impl_for, impl_for!} =
@@ -674,10 +681,16 @@ defmodule Protocol do
           end
 
         _ ->
+          structs_domain =
+            case structs do
+              [] -> Descr.none()
+              _ -> Descr.open_map(__struct__: Descr.atom(structs))
+            end
+
           domain =
-            clauses
-            |> Enum.map(fn {[domain], _} -> domain end)
-            |> Enum.reduce(&Descr.union/2)
+            Enum.reduce(types_minus_any -- structs, structs_domain, fn impl, acc ->
+              Descr.union(Module.Types.Of.impl(impl, :open), acc)
+            end)
 
           not_domain = Descr.negation(domain)
 

lib/elixir/lib/record.ex

@@ -27,8 +27,9 @@ defmodule Record do
 
   ## Types
 
-  Types can be defined for tuples with the `record/2` macro (only available in
-  typespecs). This macro will expand to a tuple as seen in the example below:
+  Types can be defined for tuples with the `record/2` construct (which is only
+  available in typespecs), with the record name as an atom and a keyword list
+  of fields and their types as argument:
 
       defmodule MyModule do
         require Record

lib/elixir/lib/regex.ex

@@ -101,6 +101,13 @@ defmodule Regex do
     * `:ungreedy` (U) - inverts the "greediness" of the regexp
       (the previous `r` option is deprecated in favor of `U`)
 
+    * `:export` (E) (since Elixir 1.19.3) - uses an exported pattern
+      which can be shared across nodes or through config, at the cost of a runtime
+      overhead every time to re-import it every time it is executed.
+      This modifier only has an effect starting on Erlang/OTP 28, and it is ignored
+      on older versions (i.e. `~r/foo/E == ~r/foo/`). This is because patterns cannot
+      and do not need to be exported in order to be shared in these versions.
+
   ## Captures
 
   Many functions in this module handle what to capture in a regex
@@ -251,7 +258,7 @@ defmodule Regex do
   This checks the version stored in the regular expression
   and recompiles the regex in case of version mismatch.
   """
-  # Remove me on Elixir v1.22
+  # TODO: Deprecate on Elixir v1.22
   @doc deprecated: "It can be removed and it has no effect"
   @doc since: "1.4.0"
   def recompile(%Regex{} = regex) do
@@ -261,7 +268,7 @@ defmodule Regex do
   @doc """
   Recompiles the existing regular expression and raises `Regex.CompileError` in case of errors.
   """
-  # Remove me on Elixir v1.22
+  # TODO: Deprecate on Elixir v1.22
   @doc deprecated: "It can be removed and it has no effect"
   @doc since: "1.4.0"
   def recompile!(regex) do
@@ -271,7 +278,7 @@ defmodule Regex do
   @doc """
   Returns the version of the underlying Regex engine.
   """
-  # Remove me on Elixir v1.22
+  # TODO: Deprecate on Elixir v1.22
   @doc deprecated: "Use :re.version() instead"
   @doc since: "1.4.0"
   def version do
@@ -515,7 +522,7 @@ defmodule Regex do
   """
   @spec names(t) :: [String.t()]
   def names(%Regex{re_pattern: re_pattern}) do
-    {:namelist, names} = :re.inspect(re_pattern, :namelist)
+    {:namelist, names} = :re.inspect(maybe_import_pattern(re_pattern), :namelist)
     names
   end
 
@@ -585,10 +592,17 @@ defmodule Regex do
       %Regex{source: source, opts: compile_opts} = regex
       :re.run(string, source, compile_opts ++ options)
     else
-      _ -> :re.run(string, re_pattern, options)
+      _ -> :re.run(string, maybe_import_pattern(re_pattern), options)
     end
   end
 
+  @compile {:inline, maybe_import_pattern: 1}
+  @compile {:no_warn_undefined, {:re, :import, 1}}
+  defp maybe_import_pattern({:re_exported_pattern, _, _, _, _} = exported),
+    do: :re.import(exported)
+
+  defp maybe_import_pattern(pattern), do: pattern
+
   @typedoc """
   Options for regex functions that capture matches.
   """
@@ -1007,6 +1021,16 @@ defmodule Regex do
     translate_options(t, [:ungreedy | acc])
   end
 
+  defp translate_options(<<?E, t::binary>>, acc) do
+    # on OTP 27-, the E modifier is a no-op since the feature doesn't exist but isn't needed
+    # (regexes aren't using references and can be shared across nodes or stored in config)
+    # TODO: remove this check on Erlang/OTP 28+ and update docs
+    case Code.ensure_loaded?(:re) and function_exported?(:re, :import, 1) do
+      true -> translate_options(t, [:export | acc])
+      false -> translate_options(t, acc)
+    end
+  end
+
   defp translate_options(<<>>, acc), do: acc
   defp translate_options(t, _acc), do: {:error, t}
 
@@ -1022,6 +1046,9 @@ defmodule Regex do
         :erlang.system_info(:otp_release) < [?2, ?8] ->
           Macro.escape(regex.re_pattern)
 
+        :lists.member(:export, regex.opts) ->
+          Macro.escape(regex.re_pattern)
+
         # OTP 28.1+ introduced the ability to export and import regexes from compiled binaries
         Code.ensure_loaded?(:re) and function_exported?(:re, :import, 1) ->
           {:ok, exported} = :re.compile(regex.source, [:export] ++ regex.opts)

lib/elixir/lib/stream.ex

@@ -964,17 +964,13 @@ defmodule Stream do
         after_fun.(user_acc)
         :erlang.raise(kind, reason, __STACKTRACE__)
     else
-      {:suspended, [val], next} ->
-        do_transform_user(val, user_acc, :cont, next, inner_acc, funs)
+      {:suspended, vals, next} ->
+        do_transform_user(:lists.reverse(vals), user_acc, :cont, next, inner_acc, funs)
 
-      {_, result} ->
+      {_, vals} ->
         # Do not attempt to call the resource again, it has either done or halted
         next = fn _ -> {:done, []} end
-
-        case result do
-          [val] -> do_transform_user(val, user_acc, :last, next, inner_acc, funs)
-          [] -> do_transform(user_acc, :last, next, inner_acc, funs)
-        end
+        do_transform_user(:lists.reverse(vals), user_acc, :last, next, inner_acc, funs)
     end
   end
 
@@ -989,7 +985,7 @@ defmodule Stream do
           after_fun.(user_acc)
           :erlang.raise(kind, reason, __STACKTRACE__)
       else
-        result -> do_transform_result(result, :halt, next, inner_acc, funs)
+        result -> do_transform_result(result, [], :halt, next, inner_acc, funs)
       end
     else
       do_transform(user_acc, :halt, next, inner_acc, funs)
@@ -1002,7 +998,11 @@ defmodule Stream do
     {:halted, elem(inner_acc, 1)}
   end
 
-  defp do_transform_user(val, user_acc, next_op, next, inner_acc, funs) do
+  defp do_transform_user([], user_acc, next_op, next, inner_acc, funs) do
+    do_transform(user_acc, next_op, next, inner_acc, funs)
+  end
+
+  defp do_transform_user([val | vals], user_acc, next_op, next, inner_acc, funs) do
     {user, _, _, _, after_fun} = funs
 
     try do
@@ -1013,20 +1013,20 @@ defmodule Stream do
         after_fun.(user_acc)
         :erlang.raise(kind, reason, __STACKTRACE__)
     else
-      result -> do_transform_result(result, next_op, next, inner_acc, funs)
+      result -> do_transform_result(result, vals, next_op, next, inner_acc, funs)
     end
   end
 
-  defp do_transform_result(result, next_op, next, inner_acc, funs) do
+  defp do_transform_result(result, vals, next_op, next, inner_acc, funs) do
     {_, fun, inner, _, after_fun} = funs
 
     case result do
       {[], user_acc} ->
-        do_transform(user_acc, next_op, next, inner_acc, funs)
+        do_transform_user(vals, user_acc, next_op, next, inner_acc, funs)
 
       {list, user_acc} when is_list(list) ->
         reduce = &Enumerable.List.reduce(list, &1, fun)
-        do_transform_inner_list(user_acc, next_op, next, inner_acc, reduce, funs)
+        do_transform_inner_list(vals, user_acc, next_op, next, inner_acc, reduce, funs)
 
       {:halt, user_acc} ->
         next.({:halt, []})
@@ -1035,11 +1035,11 @@ defmodule Stream do
 
       {other, user_acc} ->
         reduce = &Enumerable.reduce(other, &1, inner)
-        do_transform_inner_enum(user_acc, next_op, next, inner_acc, reduce, funs)
+        do_transform_inner_enum(vals, user_acc, next_op, next, inner_acc, reduce, funs)
     end
   end
 
-  defp do_transform_inner_list(user_acc, next_op, next, inner_acc, reduce, funs) do
+  defp do_transform_inner_list(vals, user_acc, next_op, next, inner_acc, reduce, funs) do
     {_, _, _, _, after_fun} = funs
 
     try do
@@ -1051,7 +1051,7 @@ defmodule Stream do
         :erlang.raise(kind, reason, __STACKTRACE__)
     else
       {:done, acc} ->
-        do_transform(user_acc, next_op, next, {:cont, acc}, funs)
+        do_transform_user(vals, user_acc, next_op, next, {:cont, acc}, funs)
 
       {:halted, acc} ->
         next.({:halt, []})
@@ -1059,12 +1059,12 @@ defmodule Stream do
         {:halted, acc}
 
       {:suspended, acc, continuation} ->
-        resume = &do_transform_inner_list(user_acc, next_op, next, &1, continuation, funs)
+        resume = &do_transform_inner_list(vals, user_acc, next_op, next, &1, continuation, funs)
         {:suspended, acc, resume}
     end
   end
 
-  defp do_transform_inner_enum(user_acc, next_op, next, {op, inner_acc}, reduce, funs) do
+  defp do_transform_inner_enum(vals, user_acc, next_op, next, {op, inner_acc}, reduce, funs) do
     {_, _, _, _, after_fun} = funs
 
     try do
@@ -1078,7 +1078,7 @@ defmodule Stream do
       # The user wanted to cont/suspend but the stream halted,
       # so we continue with the user intention.
       {:halted, [inner_op | acc]} when op != :halt and inner_op != :halt ->
-        do_transform(user_acc, next_op, next, {inner_op, acc}, funs)
+        do_transform_user(vals, user_acc, next_op, next, {inner_op, acc}, funs)
 
       {:halted, [_ | acc]} ->
         next.({:halt, []})
@@ -1086,10 +1086,10 @@ defmodule Stream do
         {:halted, acc}
 
       {:done, [_ | acc]} ->
-        do_transform(user_acc, next_op, next, {:cont, acc}, funs)
+        do_transform_user(vals, user_acc, next_op, next, {:cont, acc}, funs)
 
       {:suspended, [_ | acc], continuation} ->
-        resume = &do_transform_inner_enum(user_acc, next_op, next, &1, continuation, funs)
+        resume = &do_transform_inner_enum(vals, user_acc, next_op, next, &1, continuation, funs)
         {:suspended, acc, resume}
     end
   end

lib/elixir/pages/mix-and-otp/task-and-gen-tcp.md

@@ -228,7 +228,7 @@ Now we need to change `loop_acceptor/1` to use `Task.Supervisor` to serve each r
 ```elixir
 defp loop_acceptor(socket) do
   {:ok, client} = :gen_tcp.accept(socket)
-  {:ok, pid} = Task.Supervisor.start_child(KV.BucketSupervisor, fn -> serve(client) end)
+  {:ok, pid} = Task.Supervisor.start_child(KV.ServerSupervisor, fn -> serve(client) end)
   :ok = :gen_tcp.controlling_process(client, pid)
   loop_acceptor(socket)
 end

lib/elixir/src/elixir.erl

@@ -64,6 +64,11 @@ start(_Type, _Args) ->
       application:set_env(elixir, ansi_enabled, prim_tty:isatty(stdout) == true)
   end,
 
+  %% Store the initial dbg_callback value before any runtime modifications.
+  %% This allows Mix compiler to detect config changes vs runtime changes
+  %% (e.g., Kino wrapping dbg_callback at runtime should not trigger recompilation).
+  {ok, InitialDbgCallback} = application:get_env(elixir, dbg_callback),
+
   Tokenizer = case code:ensure_loaded('Elixir.String.Tokenizer') of
     {module, Mod} -> Mod;
     _ -> elixir_tokenizer
@@ -90,6 +95,7 @@ start(_Type, _Args) ->
     {docs, true},
     {ignore_already_consolidated, false},
     {ignore_module_conflict, false},
+    {initial_dbg_callback, InitialDbgCallback},
     {infer_signatures, [elixir]},
     {on_undefined_variable, raise},
     {parser_options, [{columns, true}]},

lib/elixir/src/elixir_erl_pass.erl

@@ -566,6 +566,11 @@ extract_bit_type({'-', _, [L, R]}, Acc) ->
 extract_bit_type({unit, _, [Arg]}, Acc) ->
   [{unit, Arg} | Acc];
 extract_bit_type({Other, _, nil}, Acc) ->
+  [Other | Acc];
+%% TODO: Remove me on Elixir v2.0.
+%% Elixir v1.14 and earlier emitted an empty list
+%% and may still be processed via debug_info.
+extract_bit_type({Other, _, []}, Acc) ->
   [Other | Acc].
 
 %% Optimizations that are specific to Erlang and change

lib/elixir/src/elixir_erl_try.erl

@@ -27,8 +27,9 @@ each_clause({'catch', Meta, Raw, Expr}, S) ->
   {Args, Guards} = elixir_utils:extract_splat_guards(Raw),
 
   Match =
+    %% TODO: Remove me on Elixir v2.0.
     %% Elixir v1.17 and earlier emitted single argument
-    %% and may still be processed via debug_info
+    %% and may still be processed via debug_info.
     case Args of
       [X] -> [throw, X];
       [X, Y] -> [X, Y]

lib/elixir/src/elixir_parser.yrl

@@ -1298,6 +1298,14 @@ warn_pipe(_Token, _) ->
   ok.
 
 %% TODO: Make this an error on v2.0
+warn_no_parens_after_do_op({{in_op, Location, Op, _InLocation}, _}) ->
+  {Line, _, _} = Location,
+
+  warn(
+    Line,
+    "missing parentheses on expression following operator \"" ++ atom_to_list(Op) ++ "\", "
+    "you must add parentheses to avoid ambiguities"
+  );
 warn_no_parens_after_do_op({{_Type, Location, Op}, _}) ->
   {Line, _, _} = Location,
 

lib/elixir/test/elixir/file_test.exs

@@ -787,6 +787,18 @@ defmodule FileTest do
       end
     end
 
+    test "cp_r! with file src and dest unknown" do
+      src = fixture_path("cp_r/a/1.txt")
+      dest = tmp_path("tmp/unknown/")
+
+      message =
+        "could not copy recursively from #{inspect(src)} to #{inspect(dest)}. #{dest}: no such file or directory"
+
+      assert_raise File.CopyError, message, fn ->
+        File.cp_r!(src, dest)
+      end
+    end
+
     test "cp preserves mode" do
       File.mkdir_p!(tmp_path("tmp"))
       src = fixture_path("cp_mode")

lib/elixir/test/elixir/fixtures/dialyzer/regressions.ex

@@ -0,0 +1,14 @@
+defmodule Dialyzer.Regressions do
+  def io_inspect_opts do
+    IO.inspect(123, label: "foo", limit: :infinity)
+  end
+
+  def format_opts do
+    Code.format_string!("",
+      line_length: 120,
+      force_do_end_blocks: true,
+      locals_without_parens: true,
+      migrate: true
+    )
+  end
+end

lib/elixir/test/elixir/inspect_test.exs

@@ -282,10 +282,15 @@ defmodule Inspect.ListTest do
 
   test "printable limit" do
     assert inspect(~c"hello world", printable_limit: 4) == ~s(~c"hell" ++ ...)
+    assert inspect(~c"hello", printable_limit: :infinity) == ~s(~c"hello")
     # Non printable characters after the limit don't matter
     assert inspect(~c"hello world" ++ [0], printable_limit: 4) == ~s(~c"hell" ++ ...)
     # Non printable strings aren't affected by printable limit
     assert inspect([0, 1, 2, 3, 4], printable_limit: 3) == ~s([0, 1, 2, 3, 4])
+    # Ensure a non-printable value after limit does not crash
+    assert inspect(~c"hello world" ++ [nil], printable_limit: 4) == ~s(~c"hell" ++ ...)
+    # Ensure a non-printable value after default limit does not hang
+    assert String.ends_with?(inspect(List.duplicate(?a, 5000) ++ [nil]), "\" ++ ...")
   end
 
   test "keyword" do
@@ -310,10 +315,20 @@ defmodule Inspect.ListTest do
     assert inspect([0], charlists: :infer) == "[0]"
   end
 
-  test "opt as strings" do
+  test "opt as charlists" do
     assert inspect(~c"john" ++ [0] ++ ~c"doe", charlists: :as_charlists) == ~s(~c"john\\0doe")
     assert inspect(~c"john", charlists: :as_charlists) == ~s(~c"john")
     assert inspect([0], charlists: :as_charlists) == ~s(~c"\\0")
+    assert inspect([nil], charlists: :as_charlists) == "[nil]"
+    assert inspect([0xD800], charlists: :as_charlists) == "[55296]"
+    assert inspect([1_114_112], charlists: :as_charlists) == "[1114112]"
+    assert inspect([[?a]], charlists: :as_charlists) == ~s([~c"a"])
+
+    assert inspect([?a, ?b, ?c | nil], charlists: :as_charlists, printable_limit: 4) ==
+             "[97, 98, 99 | nil]"
+
+    assert inspect([?a, ?b, ?c | nil], charlists: :as_charlists, printable_limit: 3) ==
+             ~s(~c"abc" ++ ...)
   end
 
   test "opt as lists" do
@@ -906,6 +921,11 @@ defmodule Inspect.OthersTest do
     assert inspect(Regex.compile!("foo", [:ucp])) == ~S'Regex.compile!("foo", [:ucp])'
   end
 
+  @tag :re_import
+  test "exported regex" do
+    assert inspect(~r/foo/E) == "~r/foo/E"
+  end
+
   test "inspect_fun" do
     fun = fn
       integer, _opts when is_integer(integer) ->

lib/elixir/test/elixir/kernel/dialyzer_test.exs

@@ -185,6 +185,11 @@ defmodule Kernel.DialyzerTest do
     assert_dialyze_no_warnings!(context)
   end
 
+  test "no warning in various non-regression cases", context do
+    copy_beam!(context, Dialyzer.Regressions)
+    assert_dialyze_no_warnings!(context)
+  end
+
   defp copy_beam!(context, module) do
     name = "#{module}.beam"
     File.cp!(Path.join(context.base_dir, name), Path.join(context.outdir, name))

lib/elixir/test/elixir/kernel/warning_test.exs

@@ -1953,6 +1953,18 @@ defmodule Kernel.WarningTest do
     )
   end
 
+  test "do+end with not in operator without explicit parentheses" do
+    assert_warn_eval(
+      ["nofile:3\n", "missing parentheses on expression following operator \"not in\""],
+      """
+      quote do
+        case do
+        end not in no_parens 1, 2
+      end
+      """
+    )
+  end
+
   test "variable is being expanded to function call (on_undefined_variable: warn)" do
     capture_io(:stderr, fn ->
       Code.put_compiler_option(:on_undefined_variable, :warn)

lib/elixir/test/elixir/list_test.exs

@@ -331,6 +331,12 @@ defmodule ListTest do
     assert_raise ArgumentError, ~r"cannot convert the given list to a string", fn ->
       List.to_string([:a, :b])
     end
+
+    invalid = List.duplicate(?a, 4096) ++ [nil]
+
+    assert_raise ArgumentError, ~r/got:\n\n\[97, 97, .*\.\.\.\]\n\z/s, fn ->
+      List.to_string(invalid)
+    end
   end
 
   test "to_charlist/1" do
@@ -349,6 +355,12 @@ defmodule ListTest do
     assert_raise ArgumentError, ~r"cannot convert the given list to a charlist", fn ->
       List.to_charlist([:a, :b])
     end
+
+    invalid = List.duplicate(?a, 4096) ++ [nil]
+
+    assert_raise ArgumentError, ~r/got:\n\n\[97, 97, .*\.\.\.\]\n\z/s, fn ->
+      List.to_charlist(invalid)
+    end
   end
 
   describe "myers_difference/2" do

lib/elixir/test/elixir/protocol/consolidation_test.exs

@@ -187,9 +187,11 @@ defmodule Protocol.ConsolidationTest do
       assert domain == [term()]
 
       assert clauses == [
-               {[Of.impl(Map)], atom([WithAny.Map])},
-               {[Of.impl(ImplStruct)], atom([WithAny.Protocol.ConsolidationTest.ImplStruct])},
-               {[negation(union(Of.impl(ImplStruct), Of.impl(Map)))], atom([WithAny.Any])}
+               {[Of.impl(Map, :open)], atom([WithAny.Map])},
+               {[Of.impl(ImplStruct, :open)],
+                atom([WithAny.Protocol.ConsolidationTest.ImplStruct])},
+               {[negation(union(Of.impl(ImplStruct, :open), Of.impl(Map, :open)))],
+                atom([WithAny.Any])}
              ]
 
       assert %{{:ok, 2} => %{sig: {:strong, nil, clauses}}} = exports
@@ -256,18 +258,34 @@ defmodule Protocol.ConsolidationTest do
       assert Inspect in protos
     end
 
+    test "protocols with expanded path" do
+      path = to_charlist(Application.app_dir(:elixir, "ebin"))
+      {:ok, mods} = :file.list_dir(path)
+      protos = Protocol.extract_protocols([{path, mods}])
+      assert Enumerable in protos
+      assert Inspect in protos
+    end
+
     test "implementations with charlist path" do
-      protos =
+      impls =
         Protocol.extract_impls(Enumerable, [to_charlist(Application.app_dir(:elixir, "ebin"))])
 
-      assert List in protos
-      assert Function in protos
+      assert List in impls
+      assert Function in impls
     end
 
     test "implementations with binary path" do
-      protos = Protocol.extract_impls(Enumerable, [Application.app_dir(:elixir, "ebin")])
-      assert List in protos
-      assert Function in protos
+      impls = Protocol.extract_impls(Enumerable, [Application.app_dir(:elixir, "ebin")])
+      assert List in impls
+      assert Function in impls
+    end
+
+    test "implementations with expanded path" do
+      path = to_charlist(Application.app_dir(:elixir, "ebin"))
+      {:ok, mods} = :file.list_dir(path)
+      impls = Protocol.extract_impls(Enumerable, [{path, mods}])
+      assert List in impls
+      assert Function in impls
     end
   end
 end

lib/elixir/test/elixir/regex_test.exs

@@ -52,6 +52,20 @@ defmodule RegexTest do
     assert Regex.match?(~r/^b$/m, "a\nb\nc")
   end
 
+  @tag :re_import
+  test "export" do
+    # exported patterns have no structs, so these are structurally equal
+    assert ~r/foo/E == Regex.compile!("foo", [:export])
+
+    assert Regex.match?(~r/foo/E, "foo")
+    refute Regex.match?(~r/foo/E, "Foo")
+
+    assert Regex.run(~r/c(d)/E, "abcd") == ["cd", "d"]
+    assert Regex.run(~r/e/E, "abcd") == nil
+
+    assert Regex.names(~r/(?<FOO>foo)/E) == ["FOO"]
+  end
+
   test "precedence" do
     assert {"aa", :unknown} |> elem(0) =~ ~r/(a)\1/
   end
@@ -113,7 +127,8 @@ defmodule RegexTest do
   test "compile!/1" do
     assert %Regex{} = Regex.compile!("foo")
 
-    assert_raise Regex.CompileError, ~r/position 0$/, fn ->
+    # The exact position changed between Erlang/OTP 28.1 and 28.3
+    assert_raise Regex.CompileError, ~r/at position/, fn ->
       Regex.compile!("*foo")
     end
   end

lib/elixir/test/elixir/stream_test.exs

@@ -183,6 +183,24 @@ defmodule StreamTest do
     assert Stream.chunk_while([1, 2, 3, 4, 5], [], chunk_fun, after_fun) |> Enum.at(0) == [1]
   end
 
+  test "chunk_while/4 regression case with concat" do
+    result =
+      ["WrongHeader\nJohn Doe", "skipped"]
+      |> Stream.take(1)
+      |> Stream.chunk_while(
+        "",
+        fn element, acc ->
+          {acc, elements} = String.split(acc <> element, "\n") |> List.pop_at(-1)
+          {:cont, elements, acc}
+        end,
+        &{:cont, [&1], []}
+      )
+      |> Stream.concat()
+      |> Enum.to_list()
+
+    assert result == ["WrongHeader", "John Doe"]
+  end
+
   test "concat/1" do
     stream = Stream.concat([1..3, [], [4, 5, 6], [], 7..9])
     assert is_function(stream)

lib/ex_unit/lib/ex_unit/assertions.ex

@@ -160,6 +160,7 @@ defmodule ExUnit.Assertions do
         end
       end
 
+    {left, right} = move_match(left, right)
     __match__(left, right, code, check, __CALLER__)
   end
 
@@ -380,6 +381,12 @@ defmodule ExUnit.Assertions do
     {ExUnit.AssertionError.no_value(), expr}
   end
 
+  defp move_match(left, {:=, meta, [middle, right]}),
+    do: move_match({:=, meta, [left, middle]}, right)
+
+  defp move_match(left, right),
+    do: {left, right}
+
   @doc false
   def __match__({:when, _, _} = left, right, _, _, _) do
     suggestion =
@@ -409,7 +416,7 @@ defmodule ExUnit.Assertions do
           case right do
             unquote(left) ->
               unquote(check)
-              unquote(mark_as_generated(vars))
+              {unquote_splicing(mark_as_generated(vars))}
 
             _ ->
               left = unquote(Macro.escape(left))
@@ -427,7 +434,7 @@ defmodule ExUnit.Assertions do
     quote do
       right = unquote(right)
       expr = unquote(code)
-      unquote(vars) = unquote(match_expr)
+      {unquote_splicing(vars)} = unquote(match_expr)
       right
     end
   end

lib/ex_unit/lib/ex_unit/callbacks.ex

@@ -169,11 +169,7 @@ defmodule ExUnit.Callbacks do
       end
   """
 
-  @type child_spec_overrides :: [
-          restart: :permanent | :transient | :temporary,
-          shutdown: :brutal_kill | timeout(),
-          type: :worker | :supervisor
-        ]
+  @type child_spec_overrides :: Supervisor.child_spec_overrides()
 
   @doc false
   def __register__(module) do

lib/ex_unit/lib/ex_unit/doc_test.ex

@@ -964,7 +964,14 @@ defmodule ExUnit.DocTest do
 
   @doc false
   defmacro __assert__({:=, _, [left, right]} = assertion) do
+    {left, right} = move_match(left, right)
     code = Macro.escape(assertion, prune_metadata: true)
     ExUnit.Assertions.__match__(left, right, code, :ok, __CALLER__)
   end
+
+  defp move_match(left, {:=, meta, [middle, right]}),
+    do: move_match({:=, meta, [left, middle]}, right)
+
+  defp move_match(left, right),
+    do: {left, right}
 end

lib/ex_unit/lib/ex_unit/formatter.ex

@@ -338,7 +338,8 @@ defmodule ExUnit.Formatter do
         {formatted_reason, wrapped_stack} =
           format_exception(test, struct, wrapped_stack, width, formatter, @counter_padding)
 
-        formatted_stack = format_stacktrace(wrapped_stack, test.module, test.name, formatter)
+        formatted_stack = format_stacktrace(wrapped_stack, test, formatter)
+
         {error_info(header, formatter) <> pad(formatted_reason <> formatted_stack), stack}
 
       :error ->
@@ -512,10 +513,15 @@ defmodule ExUnit.Formatter do
 
   defp format_diff(left, right, context, formatter) do
     if has_value?(left) and has_value?(right) do
-      {result, env} = find_diff(left, right, context)
-      result = if formatter.(:diff_enabled?, false), do: result
-      hints = Enum.map(env.hints, &{:hint, format_hint(&1)})
-      {result, hints}
+      case find_diff(left, right, context) do
+        {result, env} ->
+          result = if formatter.(:diff_enabled?, false), do: result
+          hints = Enum.map(env.hints, &{:hint, format_hint(&1)})
+          {result, hints}
+
+        nil ->
+          {nil, []}
+      end
     else
       {nil, []}
     end
@@ -672,22 +678,28 @@ defmodule ExUnit.Formatter do
     |> Algebra.format(width)
   end
 
-  defp format_stacktrace([], _case, _test, _color) do
+  defp format_stacktrace(stack, %{module: module, name: name}, color),
+    do: format_stacktrace(stack, module, name, color)
+
+  defp format_stacktrace(stack, %{name: name}, color),
+    do: format_stacktrace(stack, name, nil, color)
+
+  defp format_stacktrace([], _module, _test, _color) do
     ""
   end
 
-  defp format_stacktrace(stacktrace, test_case, test, color) do
+  defp format_stacktrace(stacktrace, module, test, color) do
     extra_info("stacktrace:", color) <>
       Enum.map_join(stacktrace, fn entry ->
-        stacktrace_info(format_stacktrace_entry(entry, test_case, test), color)
+        stacktrace_info(format_stacktrace_entry(entry, module, test), color)
       end)
   end
 
-  defp format_stacktrace_entry({test_case, test, _, location}, test_case, test) do
+  defp format_stacktrace_entry({module, test, _, location}, module, test) do
     format_file_line(location[:file], location[:line], " (test)")
   end
 
-  defp format_stacktrace_entry(entry, _test_case, _test) do
+  defp format_stacktrace_entry(entry, _module, _test) do
     format_stacktrace_entry(entry)
   end
 

lib/ex_unit/test/ex_unit/assertions_test.exs

@@ -246,6 +246,16 @@ defmodule ExUnit.AssertionsTest do
     end
   end
 
+  test "assert parallel match" do
+    assert %URI{} = uri = apply(URI, :parse, ["/foo"])
+    # This should not warn
+    assert %URI{uri | path: "/bar"}.path == "/bar"
+
+    assert uri = %URI{} = apply(URI, :parse, ["/foo"])
+    # This should not warn
+    assert %URI{uri | path: "/bar"}.path == "/bar"
+  end
+
   test "assert match with pinned variable" do
     a = 1
     {2, 1} = assert {2, ^a} = Value.tuple()

lib/ex_unit/test/ex_unit/formatter_test.exs

@@ -465,6 +465,21 @@ defmodule ExUnit.FormatterTest do
            """
   end
 
+  test "formats setup_all exit stacktraces using module context" do
+    stacktrace = [
+      {Hello, :setup_all, [], [file: __ENV__.file, line: 123]},
+      {Hello, :some_fun, [], [file: __ENV__.file, line: 456]}
+    ]
+
+    failure = [{{:EXIT, self()}, {:function_clause, stacktrace}, []}]
+
+    formatted =
+      format_test_all_failure(test_module(), failure, 1, 80, &formatter/2)
+
+    assert formatted =~ "Hello.setup_all/0"
+    assert formatted =~ "Hello.some_fun()"
+  end
+
   test "formats assertions with operators with no limit" do
     failure = [{:error, catch_assertion(assert [1, 2, 3] == [4, 5, 6]), []}]
 

lib/iex/lib/iex/evaluator.ex

@@ -71,61 +71,56 @@ defmodule IEx.Evaluator do
 
   def parse(input, opts, []), do: parse(input, opts, {[], :other})
 
-  def parse(@break_trigger, opts, _parser_state) do
-    :elixir_errors.parse_error(
-      [line: opts[:line]],
-      opts[:file],
-      "incomplete expression",
-      "",
-      {~c"", Keyword.get(opts, :line, 1), Keyword.get(opts, :column, 1), 0}
-    )
-  end
-
   def parse(input, opts, {buffer, last_op}) do
     input = buffer ++ input
     file = Keyword.get(opts, :file, "nofile")
     line = Keyword.get(opts, :line, 1)
     column = Keyword.get(opts, :column, 1)
 
-    result =
-      with {:ok, tokens} <- :elixir.string_to_tokens(input, line, column, file, opts),
-           {:ok, adjusted_tokens, adjusted_op} <-
-             adjust_operator(tokens, line, column, file, opts, last_op),
-           {:ok, forms} <- :elixir.tokens_to_quoted(adjusted_tokens, file, opts) do
-        last_op =
-          case forms do
-            {:=, _, [_, _]} -> :match
-            _ -> :other
-          end
-
-        forms =
-          if adjusted_op != nil do
-            quote do
-              IEx.Evaluator.assert_no_error!()
-              unquote(forms)
+    if List.ends_with?(input, @break_trigger) do
+      triplet = {~c"", line, column, 0}
+      :elixir_errors.parse_error([line: line], file, "incomplete expression", "", triplet)
+    else
+      result =
+        with {:ok, tokens} <- :elixir.string_to_tokens(input, line, column, file, opts),
+             {:ok, adjusted_tokens, adjusted_op} <-
+               adjust_operator(tokens, line, column, file, opts, last_op),
+             {:ok, forms} <- :elixir.tokens_to_quoted(adjusted_tokens, file, opts) do
+          last_op =
+            case forms do
+              {:=, _, [_, _]} -> :match
+              _ -> :other
             end
-          else
-            forms
-          end
 
-        {:ok, forms, last_op}
+          forms =
+            if adjusted_op != nil do
+              quote do
+                IEx.Evaluator.assert_no_error!()
+                unquote(forms)
+              end
+            else
+              forms
+            end
+
+          {:ok, forms, last_op}
+        end
+
+      case result do
+        {:ok, forms, last_op} ->
+          {:ok, forms, {[], last_op}}
+
+        {:error, {_, _, ""}} ->
+          {:incomplete, {input, last_op}}
+
+        {:error, {location, error, token}} ->
+          :elixir_errors.parse_error(
+            location,
+            file,
+            error,
+            token,
+            {input, line, column, 0}
+          )
       end
-
-    case result do
-      {:ok, forms, last_op} ->
-        {:ok, forms, {[], last_op}}
-
-      {:error, {_, _, ""}} ->
-        {:incomplete, {input, last_op}}
-
-      {:error, {location, error, token}} ->
-        :elixir_errors.parse_error(
-          location,
-          file,
-          error,
-          token,
-          {input, line, column, 0}
-        )
     end
   end
 

lib/logger/lib/logger/backends/handler.ex

@@ -47,7 +47,13 @@ defmodule Logger.Backends.Handler do
         %{truncate: truncate, utc_log: utc_log?} = config
         level = erlang_level_to_elixir_level(erl_level)
         message = Logger.Formatter.format_event(event, truncate)
-        timestamp = Map.get_lazy(metadata, :time, fn -> :os.system_time(:microsecond) end)
+
+        timestamp =
+          case metadata do
+            %{time: time} when is_integer(time) and time >= 0 -> time
+            _ -> :os.system_time(:microsecond)
+          end
+
         date_time_ms = Logger.Formatter.system_time_to_date_time_ms(timestamp, utc_log?)
         metadata = [erl_level: erl_level] ++ erlang_metadata_to_elixir_metadata(metadata)
         event = {level, gl, {Logger, message, date_time_ms, metadata}}

lib/logger/lib/logger/formatter.ex

@@ -244,26 +244,38 @@ defmodule Logger.Formatter do
     case if(is_function(enabled, 0), do: enabled.(), else: enabled) do
       true ->
         color = md[:ansi_color] || Map.fetch!(colors, level)
-        fragment = IO.ANSI.format_fragment(color, true)
-        data = IO.iodata_to_binary(data)
-        size = byte_size(data)
-
-        cond do
-          :binary.at(data, size - 2) == ?\r and :binary.at(data, size - 1) == ?\n ->
-            [fragment, binary_part(data, 0, size - 2), IO.ANSI.reset() | "\r\n"]
-
-          :binary.at(data, size - 1) == ?\n ->
-            [fragment, binary_part(data, 0, size - 1), IO.ANSI.reset(), ?\n]
-
-          true ->
-            [fragment, data | IO.ANSI.reset()]
-        end
+        [IO.ANSI.format_fragment(color, true), add_reset(data)]
 
       false ->
         data
     end
   end
 
+  defp add_reset(binary) when is_binary(binary) do
+    size = byte_size(binary)
+
+    cond do
+      binary == "" ->
+        IO.ANSI.reset()
+
+      :binary.at(binary, size - 1) == ?\n ->
+        if size > 1 and :binary.at(binary, size - 2) == ?\r do
+          [binary_part(binary, 0, size - 2), IO.ANSI.reset() | "\r\n"]
+        else
+          [binary_part(binary, 0, size - 1), IO.ANSI.reset(), ?\n]
+        end
+
+      true ->
+        [binary | IO.ANSI.reset()]
+    end
+  end
+
+  defp add_reset([?\r, ?\n]), do: [IO.ANSI.reset(), ?\r, ?\n]
+  defp add_reset([?\n]), do: [IO.ANSI.reset(), ?\n]
+  defp add_reset([last]), do: add_reset(last)
+  defp add_reset([h | t]), do: [h | add_reset(t)]
+  defp add_reset(rest), do: [rest | IO.ANSI.reset()]
+
   @doc """
   Formats the message of a log event.
   """

lib/logger/test/logger/backends/handler_test.exs

@@ -113,6 +113,12 @@ defmodule Logger.Backends.HandlerTest do
     Logger.configure_backend(Logger.Backends.Console, metadata: [])
   end
 
+  test "ignores invalid Erlang metadata" do
+    assert capture_log(fn -> :logger.info("ok", %{time: "bad"}) end) =~ "ok"
+  after
+    Logger.Backends.Internal.configure(Logger.Backends.Console, metadata: [])
+  end
+
   test "uses reporting callback with Elixir inspection" do
     assert capture_log(fn ->
              callback = fn %{hello: :world} -> {"~p~n", [:formatted]} end

lib/logger/test/logger/formatter_test.exs

@@ -105,6 +105,14 @@ defmodule Logger.FormatterTest do
           colors: [enabled: true]
         )
 
+      assert %{level: :warning, msg: {:string, ""}, meta: %{}}
+             |> format(formatter)
+             |> IO.chardata_to_string() == "\e[33m\e[0m"
+
+      assert %{level: :warning, msg: {:string, "s"}, meta: %{}}
+             |> format(formatter)
+             |> IO.chardata_to_string() == "\e[33ms\e[0m"
+
       assert %{level: :warning, msg: {:string, "message"}, meta: %{}}
              |> format(formatter)
              |> IO.chardata_to_string() == "\e[33mmessage\e[0m"
@@ -116,6 +124,18 @@ defmodule Logger.FormatterTest do
       assert %{level: :warning, msg: {:string, "message\r\n"}, meta: %{}}
              |> format(formatter)
              |> IO.chardata_to_string() == "\e[33mmessage\e[0m\r\n"
+
+      assert %{level: :warning, msg: {:string, [?é, ["message", [?\n]]]}, meta: %{}}
+             |> format(formatter)
+             |> IO.chardata_to_string() == "\e[33mémessage\e[0m\n"
+
+      assert %{level: :warning, msg: {:string, [?é, "message", ?\r, ?\n]}, meta: %{}}
+             |> format(formatter)
+             |> IO.chardata_to_string() == "\e[33mémessage\e[0m\r\n"
+
+      assert %{level: :warning, msg: {:string, [?é, "message" | "\r\n"]}, meta: %{}}
+             |> format(formatter)
+             |> IO.chardata_to_string() == "\e[33mémessage\e[0m\r\n"
     end
   end
 

lib/mix/lib/mix/compilers/elixir.ex

@@ -287,7 +287,13 @@ defmodule Mix.Compilers.Elixir do
   end
 
   defp deps_config_compile_env_apps(deps_config) do
-    if deps_config[:dbg] != Application.fetch_env!(:elixir, :dbg_callback) do
+    # Use initial_dbg_callback instead of dbg_callback to ignore runtime modifications.
+    # Tools like Kino modify dbg_callback at runtime to customize dbg/2 behavior,
+    # but this should not trigger recompilation since the config hasn't actually changed.
+    # initial_dbg_callback is set when :elixir app starts, before any runtime modifications.
+    initial_dbg = :elixir_config.get(:initial_dbg_callback)
+
+    if deps_config[:dbg] != initial_dbg do
       [:elixir]
     else
       []

lib/mix/lib/mix/compilers/protocol.ex

@@ -126,11 +126,16 @@ defmodule Mix.Compilers.Protocol do
   end
 
   defp consolidation_paths do
-    filter_otp(:code.get_path(), :code.lib_dir())
-  end
+    otp = :code.lib_dir()
 
-  defp filter_otp(paths, otp) do
-    Enum.filter(paths, &(not :lists.prefix(otp, &1)))
+    # Pre-list the paths in each directory for performance
+    for path <- :code.get_path(), not :lists.prefix(otp, path) do
+      {path,
+       case :file.list_dir(path) do
+         {:ok, files} -> files
+         _ -> []
+       end}
+    end
   end
 
   defp consolidate([], _paths, output, _opts) do

lib/mix/lib/mix/release.ex

@@ -468,51 +468,48 @@ defmodule Mix.Release do
     {sys_config, runtime_config?} =
       merge_provider_config(release, sys_config, config_provider_path)
 
-    path = Path.join(release.version_path, "sys.config")
-
-    args = [runtime_config?, sys_config]
-    format = "%% coding: utf-8~n%% RUNTIME_CONFIG=~s~n~tw.~n"
-    File.mkdir_p!(Path.dirname(path))
-    File.write!(path, IO.chardata_to_string(:io_lib.format(format, args)))
-
-    case :file.consult(path) do
-      {:ok, _} ->
+    case consultable_sys_config(sys_config) do
+      {:ok, contents} ->
+        path = Path.join(release.version_path, "sys.config")
+        args = [runtime_config?, contents]
+        format = "%% coding: utf-8~n%% RUNTIME_CONFIG=~s~n~ts.~n"
+        File.mkdir_p!(Path.dirname(path))
+        File.write!(path, IO.chardata_to_string(:io_lib.format(format, args)))
         :ok
 
-      {:error, reason} ->
-        invalid =
-          for {app, kv} <- sys_config,
-              {key, value} <- kv,
-              not valid_config?(value),
-              do: """
-
-              Application: #{inspect(app)}
-              Key: #{inspect(key)}
-              Value: #{inspect(value)}
-              """
-
-        message =
-          case invalid do
-            [] ->
-              "Could not read configuration file. Reason: #{inspect(reason)}"
-
-            _ ->
-              "Could not read configuration file. It has invalid configuration terms " <>
-                "such as functions, references, and pids. Please make sure your configuration " <>
-                "is made of numbers, atoms, strings, maps, tuples and lists. The following entries " <>
-                "are wrong:\n#{Enum.join(invalid)}"
-          end
-
+      {:error, message} ->
         {:error, message}
     end
   end
 
-  defp valid_config?(m) when is_map(m),
-    do: Enum.all?(Map.delete(m, :__struct__), &valid_config?/1)
+  defp consultable_sys_config(sys_config) do
+    contents =
+      Enum.map_intersperse(sys_config, ?,, fn {app, kv} ->
+        kv =
+          Enum.map_intersperse(kv, ?,, fn {key, value} ->
+            case Mix.Utils.consultable(value) do
+              {:ok, value} -> [?{, :io_lib.print(key), ?,, value, ?}]
+              {:error, term, reason} -> throw({:error, app, key, term, reason})
+            end
+          end)
 
-  defp valid_config?(l) when is_list(l), do: Enum.all?(l, &valid_config?/1)
-  defp valid_config?(t) when is_tuple(t), do: Enum.all?(Tuple.to_list(t), &valid_config?/1)
-  defp valid_config?(o), do: is_number(o) or is_atom(o) or is_binary(o)
+        [?{, :io_lib.print(app), ?,, ?[, kv, ?], ?}]
+      end)
+
+    {:ok, [?[, contents, ?]]}
+  catch
+    {:error, app, key, value, reason} ->
+      message = """
+      Could not write configuration file because it has invalid terms
+
+      Application: #{inspect(app)}
+      Key: #{inspect(key)}
+      Invalid value: #{inspect(value)}
+      Reason: #{reason}
+      """
+
+      {:error, message}
+  end
 
   defp merge_provider_config(%{config_providers: []}, sys_config, _), do: {sys_config, false}
 

lib/mix/lib/mix/task.compiler.ex

@@ -295,10 +295,24 @@ defmodule Mix.Task.Compiler do
   end
 
   defp run_compiler(compiler, args) do
-    result = normalize(Mix.Task.run("compile.#{compiler}", args), compiler)
+    args_maybe_force = maybe_prepend_force(args, compiler)
+    result = normalize(Mix.Task.run("compile.#{compiler}", args_maybe_force), compiler)
     Enum.reduce(Mix.ProjectStack.pop_after_compiler(compiler), result, & &1.(&2))
   end
 
+  defp maybe_prepend_force(args, compiler) do
+    args
+    |> Enum.any?(fn
+      "--force-" <> rest -> rest == compiler |> to_string() |> String.replace("_", "-")
+      _ -> false
+    end)
+    |> if do
+      ["--force" | args]
+    else
+      args
+    end
+  end
+
   # Normalize the compiler result to a diagnostic tuple
   defp normalize(result, name) do
     case result do

lib/mix/lib/mix/tasks/cmd.ex

@@ -26,7 +26,7 @@ defmodule Mix.Tasks.Cmd do
   Your shell will expand "lib/*" and then pass multiple arguments to
   `mix cmd`, which in turn passes them to `echo`. Note that, `mix cmd`
   by itself, does not perform any shell expansion. This means that,
-  if you invoke `mix cmd` programatically, as in:
+  if you invoke `mix cmd` programmatically, as in:
 
       Mix.Task.run("cmd", ["echo", "lib/*"])
 

lib/mix/lib/mix/tasks/compile.app.ex

@@ -187,12 +187,22 @@ defmodule Mix.Tasks.Compile.App do
         |> add_compile_env(current_properties)
         |> add_modules(modules, compile_path)
 
-      contents = to_erl_term({:application, app, properties})
+      contents =
+        case Mix.Utils.consultable({:application, app, properties}) do
+          {:ok, contents} ->
+            contents
+
+          {:error, term, reason} ->
+            Mix.raise(
+              "\"def application\" has a term which cannot be written to .app files: #{inspect(term)} (#{reason})"
+            )
+        end
+
       :application.unload(app)
       :application.load({:application, app, properties})
 
       Mix.Project.ensure_structure()
-      File.write!(target, [contents, ?.])
+      File.write!(target, IO.chardata_to_string([contents, ?.]))
       File.touch!(target, new_mtime)
 
       # If we just created the .app file, it will have touched
@@ -209,53 +219,6 @@ defmodule Mix.Tasks.Compile.App do
     end
   end
 
-  defp to_erl_term(tuple) when is_tuple(tuple) do
-    [?{, tuple |> Tuple.to_list() |> to_erl_head(), ?}]
-  end
-
-  defp to_erl_term(list) when is_list(list) do
-    [?[, to_erl_head(list), ?]]
-  end
-
-  defp to_erl_term(map) when is_map(map) do
-    inner =
-      Enum.map_intersperse(
-        :maps.to_list(:maps.iterator(map, :reversed)),
-        ?,,
-        fn {key, value} -> [to_erl_term(key), "=>", to_erl_term(value)] end
-      )
-
-    [?#, ?{, inner, ?}]
-  end
-
-  defp to_erl_term(map) when is_map(map) do
-    inner =
-      Enum.map_intersperse(
-        :maps.to_list(:maps.iterator(map, :reversed)),
-        ?,,
-        fn {key, value} -> [to_erl_term(key), "=>", to_erl_term(value)] end
-      )
-
-    [?#, ?{, inner, ?}]
-  end
-
-  defp to_erl_term(term) when is_function(term) or is_reference(term) or is_pid(term) do
-    Mix.raise(
-      "\"def application\" has a term which cannot be written to .app files: #{inspect(term)}"
-    )
-  end
-
-  defp to_erl_term(term) do
-    :io_lib.print(term)
-  end
-
-  defp to_erl_head([]), do: []
-  defp to_erl_head([h | t]), do: [to_erl_term(h) | to_erl_tail(t)]
-
-  defp to_erl_tail([h | t]), do: [?,, to_erl_term(h) | to_erl_tail(t)]
-  defp to_erl_tail([]), do: []
-  defp to_erl_tail(other), do: [?|, to_erl_term(other)]
-
   defp current_app_properties(target) do
     case :file.consult(target) do
       {:ok, [{:application, _app, properties}]} -> properties

lib/mix/lib/mix/tasks/compile.ex

@@ -7,7 +7,7 @@ defmodule Mix.Tasks.Compile do
 
   @shortdoc "Compiles source files"
 
-  @moduledoc """
+  @moduledoc ~S"""
   The main entry point to compile source files.
 
   It simply runs the compilers registered in your project and returns
@@ -59,7 +59,9 @@ defmodule Mix.Tasks.Compile do
     * `--all-warnings` (`--no-all-warnings`) - prints all warnings, including previous compilations
       (default is true except on errors)
     * `--erl-config` - path to an Erlang term file that will be loaded as Mix config
-    * `--force` - forces compilation
+    * `--force` - forces compilation. You can also specify `--force-#{compiler}` for each compiler
+      invoked to force specifically that compiler to run (it requires the compiler to respect the
+      `--force` option, which is advised)
     * `--list` - lists all enabled compilers
     * `--listeners` - starts Mix listeners (they are started by default,
       unless `--no-listeners` or `--no-deps-check` are given)

lib/mix/lib/mix/tasks/escript.build.ex

@@ -271,7 +271,8 @@ defmodule Mix.Tasks.Escript.Build do
     []
   end
 
-  defp extra_apps_in_app_tree(app) when app in [:eex, :ex_unit, :iex, :logger, :mix] do
+  # We include hex in here as it is always an archive and it cannot be depended on
+  defp extra_apps_in_app_tree(app) when app in [:eex, :ex_unit, :iex, :logger, :mix, :hex] do
     [app]
   end
 

lib/mix/lib/mix/tasks/help.ex

@@ -112,12 +112,26 @@ defmodule Mix.Tasks.Help do
 
   def run(["app:" <> app]) do
     loadpaths!()
+
     app = String.to_atom(app)
 
+    # If the application is not available, attempt to load it from Erlang/Elixir
+    if is_nil(Application.spec(app, :vsn)) do
+      try do
+        Mix.ensure_application!(app)
+      rescue
+        _ ->
+          # Otherwise, it may be a dep or the current project not yet compiled
+          if Mix.Project.get() do
+            Mix.Task.run("compile")
+          end
+      end
+    end
+
     if modules = Application.spec(app, :modules) do
       for module <- modules,
           not (module |> Atom.to_string() |> String.starts_with?("Elixir.Mix.Tasks.")),
-          {:docs_v1, _, :elixir, "text/markdown", %{"en" => <<doc::binary>>}, _, _} <-
+          {:docs_v1, _, _, "text/markdown", %{"en" => <<doc::binary>>}, _, _} <-
             [Code.fetch_docs(module)] do
         leading = doc |> String.split(["\n\n", "\r\n\r\n"], parts: 2) |> hd()
         "# #{inspect(module)}\n#{leading}\n"

lib/mix/lib/mix/tasks/xref.ex

@@ -44,12 +44,22 @@ defmodule Mix.Tasks.Xref do
                   └── lib/a.ex
 
   Because you have a compile-time dependency, any of the files `lib/a.ex`,
-  `lib/b.ex`, and `lib/c.ex` depend on will cause the whole cycle to
-  recompile. Therefore, your first priority to reduce compile times is
-  to remove such cycles. You can spot them by running:
+  `lib/b.ex`, and `lib/c.ex` depend on will cause `lib/a.ex` to recompile.
+  In other words, whenever you have a cycle, **a change to any file in the
+  cycle will cause all compile-time deps to recompile**. Therefore, your
+  first priority to reduce constant recompilations is to remove them.
+  You can spot them by running:
 
       $ mix xref graph --format cycles --label compile-connected
 
+  > #### Use the --label option
+  >
+  > The job of `mix xref` is to explore relationships between files
+  > and it is expected that most of your files are either directly
+  > or indirectly connected. For this reason, it is strongly advised
+  > to pass the `--label` option to filter the amount of data,
+  > specifically with `compile-connected` (or `compile`) as values.
+
   Whenever you find a compile-time dependency, such as `lib/a.ex` pointing
   to `lib/b.ex`, there are two ways to remove them:
 
@@ -208,13 +218,11 @@ defmodule Mix.Tasks.Xref do
     * `--exclude` - path to exclude. Can be repeated to exclude multiple paths.
 
     * `--label` - only shows relationships with the given label.
-      The labels are "compile", "export" and "runtime". By default, the `--label`
-      option does not change how the graph is computed, it simply filters the
-      printed graph to show only relationships with the given label. However,
-      you can pass `--only-direct` to trim the graph to only the nodes that
-      have the direct relationship given by label. There is also a special
-      label called "compile-connected" that keeps only compile-time files with
-      at least one transitive dependency. See "Dependency types" section below.
+      The labels are "compile-connected", "compile", "export" and "runtime".
+      By default, the `--label` option does not change how the graph is computed,
+      it simply filters the printed graph to show only relationships with the given
+      label. However, you can pass `--only-direct` to trim the graph to only the
+      nodes that have the direct relationship given by label.
 
     * `--group` - provide comma-separated paths to consider as a group. Dependencies
       from and into multiple files of the group are considered a single dependency.
@@ -239,6 +247,9 @@ defmodule Mix.Tasks.Xref do
     * `--min-cycle-size` - controls the minimum cycle size on formats
       like `stats` and `cycles`
 
+    * `--min-cycle-label` - controls the minimum number of dependencies
+      with the given `--label` on a cycle
+
     * `--format` - can be set to one of:
 
       * `pretty` - prints the graph to the terminal using Unicode characters.
@@ -435,6 +446,7 @@ defmodule Mix.Tasks.Xref do
     sink: :keep,
     source: :keep,
     min_cycle_size: :integer,
+    min_cycle_label: :integer,
     output: :string
   ]
 
@@ -1218,9 +1230,22 @@ defmodule Mix.Tasks.Xref do
         cycles
       end
 
-    # :compile_connected is the same
+    min_cycle_label =
+      if integer = opts[:min_cycle_label] do
+        if filter == :all do
+          Mix.raise("--min-cycle-label requires the --label option to be given")
+        end
+
+        integer
+      else
+        1
+      end
+
+    # :compile_connected is the same as :compile
     if cycle_fn = cycle_filter_fn(filter) do
-      Enum.filter(cycles, fn {_length, cycle} -> Enum.any?(cycle, cycle_fn) end)
+      Enum.filter(cycles, fn {_length, cycle} ->
+        Enum.count_until(cycle, cycle_fn, min_cycle_label) == min_cycle_label
+      end)
     else
       cycles
     end
@@ -1269,11 +1294,35 @@ defmodule Mix.Tasks.Xref do
           shell.info("#{length(cycles)} cycles found. Showing them in decreasing size:\n")
 
           for {length, cycle} <- cycles do
-            shell.info("Cycle of length #{length}:\n")
+            meta =
+              cycle
+              |> Enum.reduce({0, 0}, fn
+                {_, :compile}, {compile, export} -> {compile + 1, export}
+                {_, :export}, {compile, export} -> {compile, export + 1}
+                {_, _}, {compile, export} -> {compile, export}
+              end)
+              |> case do
+                {0, 0} ->
+                  ""
+
+                {compile, export} ->
+                  info =
+                    if(compile > 0, do: ["#{compile} compile"], else: []) ++
+                      if(export > 0, do: ["#{export} export"], else: [])
+
+                  " (" <> Enum.join(info, ", ") <> ")"
+              end
+
+            shell.info("Cycle of length #{length}#{meta}:\n")
 
             for {node, type} <- cycle do
-              type = if type, do: " (#{type})", else: ""
-              shell.info("    " <> node <> type)
+              shell.info(
+                case type do
+                  :compile -> [:red, "    #{node} (compile)"]
+                  :export -> "    #{node} (export)"
+                  _ -> "    #{node}"
+                end
+              )
             end
 
             shell.info("")

lib/mix/lib/mix/utils.ex

@@ -907,4 +907,77 @@ defmodule Mix.Utils do
         uid
     end
   end
+
+  @doc """
+  Convert the given terms to a consultable Erlang term.
+  """
+  def consultable(term) do
+    {:ok, to_erl_term(term)}
+  catch
+    {:error, term, reason} -> {:error, term, reason}
+  end
+
+  defp to_erl_term(tuple) when is_tuple(tuple) do
+    [?{, tuple |> Tuple.to_list() |> to_erl_head(), ?}]
+  end
+
+  defp to_erl_term(list) when is_list(list) do
+    if List.ascii_printable?(list) do
+      :io_lib.print(list)
+    else
+      [?[, to_erl_head(list), ?]]
+    end
+  end
+
+  defp to_erl_term(%Regex{re_pattern: {:re_pattern, _, _, _, ref}} = regex)
+       when is_reference(ref) do
+    throw({:error, regex, "you must use the /E modifier to store regexes"})
+  end
+
+  defp to_erl_term(map) when is_map(map) do
+    inner =
+      Enum.map_intersperse(
+        :maps.to_list(:maps.iterator(map, :reversed)),
+        ?,,
+        fn {key, value} -> [to_erl_term(key), "=>", to_erl_term(value)] end
+      )
+
+    [?#, ?{, inner, ?}]
+  end
+
+  defp to_erl_term(map) when is_map(map) do
+    inner =
+      Enum.map_intersperse(
+        :maps.to_list(:maps.iterator(map, :reversed)),
+        ?,,
+        fn {key, value} -> [to_erl_term(key), "=>", to_erl_term(value)] end
+      )
+
+    [?#, ?{, inner, ?}]
+  end
+
+  defp to_erl_term(function) when is_function(function) do
+    fun_info = Function.info(function)
+
+    if fun_info[:type] == :external and fun_info[:env] == [] do
+      :io_lib.print(function)
+    else
+      throw({:error, function, "only functions in the form &Mod.fun/arity are allowed"})
+    end
+  end
+
+  defp to_erl_term(term) when is_reference(term) or is_pid(term) do
+    throw({:error, term, "PIDs and References are not supported"})
+  end
+
+  defp to_erl_term(term) do
+    :io_lib.print(term)
+  end
+
+  defp to_erl_head([]), do: []
+  defp to_erl_head([h | t]), do: [to_erl_term(h) | to_erl_tail(t)]
+
+  defp to_erl_tail([h | t]), do: [?,, to_erl_term(h) | to_erl_tail(t)]
+  defp to_erl_tail([]), do: []
+  defp to_erl_tail(other), do: [?|, to_erl_term(other)]
 end

lib/mix/test/mix/release_test.exs

@@ -592,19 +592,20 @@ defmodule Mix.ReleaseTest do
       assert make_sys_config(release([]), [foo: [bar: :baz]], "unused/runtime/path") == :ok
       contents = File.read!(@sys_config)
       assert contents =~ "%% RUNTIME_CONFIG=false"
-      assert contents =~ "[{foo,[{bar,baz}]}]."
+      {:ok, contents} = :file.consult(@sys_config)
+      assert contents == [[foo: [bar: :baz]]]
     end
 
     test "writes sys_config with encoding" do
       assert make_sys_config(
                release([]),
-               [encoding: {:_μ, :"£", "£", ~c"£"}],
+               [encoding: [key: {:_μ, :"£", "£", ~c"£"}]],
                "unused/runtime/path"
              ) ==
                :ok
 
       {:ok, contents} = :file.consult(@sys_config)
-      assert contents == [[encoding: {:_μ, :"£", "£", ~c"£"}]]
+      assert contents == [[encoding: [key: {:_μ, :"£", "£", ~c"£"}]]]
     end
 
     test "writes the given sys_config with config providers" do
@@ -649,12 +650,12 @@ defmodule Mix.ReleaseTest do
     end
 
     test "errors on bad config" do
-      assert {:error, "Could not read configuration file." <> _} =
+      assert {:error, "Could not write configuration file " <> _} =
                make_sys_config(release([]), [foo: [bar: self()]], "unused/runtime/path")
 
       env = %{__ENV__ | lexical_tracker: self()}
 
-      assert {:error, "Could not read configuration file." <> _} =
+      assert {:error, "Could not write configuration file " <> _} =
                make_sys_config(release([]), [foo: [bar: env]], "unused/runtime/path")
     end
   end

lib/mix/test/mix/tasks/compile.app_test.exs

@@ -110,7 +110,7 @@ defmodule Mix.Tasks.Compile.AppTest do
   test "uses custom application settings" do
     in_fixture("no_mixfile", fn ->
       Mix.Project.push(CustomProject)
-      env = [foo: [:one, "two", 3, 4], bar: [{} | %{foo: :bar}]]
+      env = [foo: [:one, "two", 3, 4, "฿", &List.flatten/1], bar: [{} | %{foo: :bar}]]
 
       Process.put(:application,
         maxT: :infinity,
@@ -132,7 +132,10 @@ defmodule Mix.Tasks.Compile.AppTest do
       assert properties[:applications] ==
                [:kernel, :stdlib, :elixir, :logger, :ex_unit, :example_app, :mix]
 
-      assert properties[:env] == [foo: [:one, "two", 3, 4], bar: [{} | %{foo: :bar}]]
+      assert properties[:env] == [
+               foo: [:one, "two", 3, 4, "฿", &List.flatten/1],
+               bar: [{} | %{foo: :bar}]
+             ]
 
       refute Keyword.has_key?(properties, :extra_applications)
     end)
@@ -260,6 +263,25 @@ defmodule Mix.Tasks.Compile.AppTest do
     end)
   end
 
+  @tag :re_import
+  test "accepts only regexes without a reference" do
+    in_fixture("no_mixfile", fn ->
+      Mix.Project.push(CustomProject)
+      Process.put(:application, env: [regex: ~r/foo/])
+
+      assert_raise Mix.Error, ~r/you must use the \/E modifier to store regexes/, fn ->
+        Mix.Tasks.Compile.App.run([])
+      end
+
+      Process.put(:application, env: [exported: ~r/foo/E])
+      Mix.Tasks.Compile.Elixir.run([])
+      Mix.Tasks.Compile.App.run([])
+
+      properties = parse_resource_file(:custom_project)
+      assert properties[:env] == [exported: ~r/foo/E]
+    end)
+  end
+
   test ".app contains description and registered (as required by systools)" do
     in_fixture("no_mixfile", fn ->
       Mix.Project.push(MixTest.Case.Sample)

lib/mix/test/mix/tasks/compile.elixir_test.exs

@@ -278,9 +278,11 @@ defmodule Mix.Tasks.Compile.ElixirTest do
       assert_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
       assert_received {:mix_shell, :info, ["Compiled lib/b.ex"]}
 
-      # Change the dbg_callback at runtime
+      # Simulate a config change by updating both dbg_callback and initial_dbg_callback.
+      # This represents the case where the user actually changed the config file.
       File.touch!("_build/dev/lib/sample/.mix/compile.elixir", @old_time)
       Application.put_env(:elixir, :dbg_callback, {__MODULE__, :dbg, []})
+      :elixir_config.put(:initial_dbg_callback, {__MODULE__, :dbg, []})
 
       assert Mix.Tasks.Compile.Elixir.run(["--verbose"]) == {:ok, []}
       assert_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
@@ -289,6 +291,35 @@ defmodule Mix.Tasks.Compile.ElixirTest do
     end)
   after
     Application.put_env(:elixir, :dbg_callback, {Macro, :dbg, []})
+    :elixir_config.put(:initial_dbg_callback, {Macro, :dbg, []})
+  end
+
+  test "does not recompile when dbg_callback is modified at runtime but initial is unchanged" do
+    in_fixture("no_mixfile", fn ->
+      Mix.Project.push(MixTest.Case.Sample)
+
+      File.write!("lib/a.ex", """
+      defmodule A do
+        def a, do: dbg(:ok)
+      end
+      """)
+
+      assert Mix.Tasks.Compile.Elixir.run(["--verbose"]) == {:ok, []}
+      assert_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
+
+      # Simulate a tool like Kino modifying dbg_callback at runtime.
+      # Since initial_dbg_callback remains unchanged, this should NOT trigger recompilation.
+      original_dbg = Application.fetch_env!(:elixir, :dbg_callback)
+      :elixir_config.put(:initial_dbg_callback, original_dbg)
+      Application.put_env(:elixir, :dbg_callback, {SomeDebugTool, :dbg, [original_dbg]})
+
+      # Should NOT trigger recompilation since initial_dbg_callback is unchanged
+      assert Mix.Tasks.Compile.Elixir.run(["--verbose"]) == {:noop, []}
+      refute_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
+    end)
+  after
+    Application.put_env(:elixir, :dbg_callback, {Macro, :dbg, []})
+    :elixir_config.put(:initial_dbg_callback, {Macro, :dbg, []})
   end
 
   test "recompiles files when config changes export dependencies" do
@@ -1253,6 +1284,23 @@ defmodule Mix.Tasks.Compile.ElixirTest do
     end)
   end
 
+  test "recompiles with --force-elixir" do
+    in_fixture("no_mixfile", fn ->
+      Mix.Project.push(MixTest.Case.Sample)
+      assert Mix.Task.run("compile") == {:ok, []}
+      purge([A, B])
+
+      # Now we have a noop
+      Mix.Task.clear()
+      assert Mix.Task.run("compile") == {:noop, []}
+
+      # --force-elixir
+      Mix.Task.clear()
+      assert Mix.Task.run("compile", ["--verbose", "--force-elixir"]) == {:ok, []}
+      assert_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
+    end)
+  end
+
   test "compiles files with autoload disabled" do
     in_fixture("no_mixfile", fn ->
       Mix.Project.push(MixTest.Case.Sample)

lib/mix/test/mix/tasks/help_test.exs

@@ -199,20 +199,64 @@ defmodule Mix.Tasks.HelpTest do
     in_tmp(context.test, fn ->
       output =
         capture_io(fn ->
-          Mix.Tasks.Help.run(["app:mix"])
+          Mix.Tasks.Help.run(["app:iex"])
         end)
 
-      assert output =~ "# Mix\n\nMix is a build tool"
+      assert output =~ "# IEx\n\nElixir's interactive shell."
+
+      if System.otp_release() >= "27" do
+        output =
+          capture_io(fn ->
+            Mix.Tasks.Help.run(["app:parsetools"])
+          end)
+
+        assert output =~ "# :leex"
+      end
     end)
   end
 
-  test "help unknown app:APP", context do
+  test "help app:UNKNOWN", context do
     in_tmp(context.test, fn ->
       Mix.Tasks.Help.run(["app:foobar"])
       assert_received {:mix_shell, :error, ["Application foobar does not exist or is not loaded"]}
     end)
   end
 
+  defmodule ExampleProject do
+    def project do
+      [
+        app: :sample,
+        version: "0.1.0"
+      ]
+    end
+  end
+
+  test "help app:APP for current project", context do
+    in_tmp(context.test, fn ->
+      Mix.Project.push(ExampleProject)
+      File.mkdir_p!("lib")
+
+      File.write!("lib/example.ex", ~s'''
+      defmodule Example do
+        @moduledoc """
+        This is an example module.
+        """
+      end
+      ''')
+
+      output =
+        capture_io(fn ->
+          Mix.Tasks.Help.run(["app:sample"])
+        end)
+
+      assert output =~ """
+             # Example
+
+             This is an example module.
+             """
+    end)
+  end
+
   test "help Elixir MODULE", context do
     in_tmp(context.test, fn ->
       output =

lib/mix/test/mix/tasks/xref_test.exs

@@ -500,7 +500,7 @@ defmodule Mix.Tasks.XrefTest do
       assert_graph(["--format", "cycles"], """
       1 cycles found. Showing them in decreasing size:
 
-      Cycle of length 2:
+      Cycle of length 2 (1 compile):
 
           lib/a.ex (compile)
           lib/b.ex
@@ -512,7 +512,7 @@ defmodule Mix.Tasks.XrefTest do
       assert_graph(["--format", "cycles", "--label", "compile"], """
       1 cycles found. Showing them in decreasing size:
 
-      Cycle of length 2:
+      Cycle of length 2 (1 compile):
 
           lib/a.ex (compile)
           lib/b.ex
@@ -524,7 +524,7 @@ defmodule Mix.Tasks.XrefTest do
       assert_graph(["--format", "cycles", "--label", "compile-connected"], """
       1 cycles found. Showing them in decreasing size:
 
-      Cycle of length 2:
+      Cycle of length 2 (1 compile):
 
           lib/a.ex (compile)
           lib/b.ex
@@ -539,7 +539,7 @@ defmodule Mix.Tasks.XrefTest do
         assert_graph(["--format", "cycles", "--fail-above", "0"], """
         1 cycles found. Showing them in decreasing size:
 
-        Cycle of length 2:
+        Cycle of length 2 (1 compile):
 
             lib/a.ex (compile)
             lib/b.ex
@@ -548,11 +548,11 @@ defmodule Mix.Tasks.XrefTest do
       end
     end
 
-    test "cycles with min_cycle_size matching actual length" do
-      assert_graph(["--format", "cycles", "--min-cycle-size", "2"], """
+    test "cycles with min_cycle_label matching actual length" do
+      assert_graph(["--format", "cycles", "--label", "compile", "--min-cycle-label", "1"], """
       1 cycles found. Showing them in decreasing size:
 
-      Cycle of length 2:
+      Cycle of length 2 (1 compile):
 
           lib/a.ex (compile)
           lib/b.ex
@@ -560,6 +560,24 @@ defmodule Mix.Tasks.XrefTest do
       """)
     end
 
+    test "cycles with min_cycle_size matching actual length" do
+      assert_graph(["--format", "cycles", "--min-cycle-size", "2"], """
+      1 cycles found. Showing them in decreasing size:
+
+      Cycle of length 2 (1 compile):
+
+          lib/a.ex (compile)
+          lib/b.ex
+
+      """)
+    end
+
+    test "cycles with min_cycle_label greater than actual length" do
+      assert_graph(["--format", "cycles", "--label", "compile", "--min-cycle-label", "2"], """
+      No cycles found
+      """)
+    end
+
     test "cycles with min_cycle_size greater than actual length" do
       assert_graph(["--format", "cycles", "--min-cycle-size", "3"], """
       No cycles found

lib/mix/test/test_helper.exs

@@ -43,12 +43,22 @@ cover_exclude =
     []
   end
 
+# OTP 28.1+
+re_import_exclude =
+  if Code.ensure_loaded?(:re) and function_exported?(:re, :import, 1) do
+    []
+  else
+    [:re_import]
+  end
+
 Code.require_file("../../elixir/scripts/cover_record.exs", __DIR__)
 CoverageRecorder.maybe_record("mix")
 
 ExUnit.start(
   trace: !!System.get_env("TRACE"),
-  exclude: epmd_exclude ++ os_exclude ++ git_exclude ++ line_exclude ++ cover_exclude,
+  exclude:
+    epmd_exclude ++
+      os_exclude ++ git_exclude ++ line_exclude ++ cover_exclude ++ re_import_exclude,
   include: line_include,
   assert_receive_timeout: String.to_integer(System.get_env("ELIXIR_ASSERT_TIMEOUT", "300"))
 )