Add a note about native code in mix releases, closes #14386

Author: josevalim

lib/elixir/lib/kernel/parallel_compiler.ex

@@ -135,7 +135,13 @@ defmodule Kernel.ParallelCompiler do
 
     * `:each_long_compilation` - for each file that takes more than a given
       timeout (see the `:long_compilation_threshold` option) to compile, invoke
-      this callback passing the file as its argument
+      this callback passing the file as its argument (and optionally the PID
+      of the process compiling the file)
+
+    * `:each_long_verification` (since v1.19.0) - for each file that takes more
+      than a given timeout (see the `:long_verification_threshold` option) to
+      compile, invoke this callback passing the module as its argument (and
+      optionally the PID of the process verifying the module)
 
     * `:each_module` - for each module compiled, invokes the callback passing
       the file, module and the module bytecode
@@ -147,11 +153,14 @@ defmodule Kernel.ParallelCompiler do
       * `{:runtime, modules, warnings}` - to stop compilation and verify the list
         of modules because dependent modules have changed
 
-    * `:long_compilation_threshold` - the timeout (in seconds) to check for modules
+    * `:long_compilation_threshold` - the timeout (in seconds) to check for files
       taking too long to compile. For each file that exceeds the threshold, the
-      `:each_long_compilation` callback is invoked. From Elixir v1.11, only the time
-      spent compiling the actual module is taken into account by the threshold, the
-      time spent waiting is not considered. Defaults to `10` seconds.
+      `:each_long_compilation` callback is invoked. Defaults to `10` seconds.
+
+    * `:long_verification_threshold` (since v1.19.0) - the timeout (in seconds) to
+      check for modules taking too long to compile. For each module that exceeds the
+      threshold, the `:each_long_verification` callback is invoked. Defaults to
+      `10` seconds.
 
     * `:profile` - if set to `:time` measure the compilation time of each compilation cycle
        and group pass checker

lib/mix/lib/mix/tasks/release.ex

@@ -682,7 +682,10 @@ defmodule Mix.Tasks.Release do
       You can configure the "tmp" directory by setting the `RELEASE_TMP` environment
       variable, either explicitly or inside your `releases/RELEASE_VSN/env.sh`
       (or `env.bat` on Windows). Defaults to `true` if using the deprecated
-      `config/releases.exs`, `false` otherwise.
+      `config/releases.exs`, `false` otherwise. Be careful of which libraries you
+      load when setting this option to true, if a library is loaded early during
+      configuration and it includes native code, it may not actually be able to
+      restart cleanly.
 
     * `:prune_runtime_sys_config_after_boot` - if `:reboot_system_after_config`
       is set, every time your system boots, the release will write a config file