From 8e53a619ea956fde28d03a559241f5fd4dcacdca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20=C5=81=C4=99picki?=
 <michallepicki@users.noreply.github.com>
Date: Mon, 22 Apr 2024 20:08:29 +0200
Subject: [PATCH 1/4] Expose getting process dictionary value for specific key
 in Process.info/2

This functionality is present since OTP 26.2:
https://github.com/erlang/otp/pull/7707
---
 lib/elixir/lib/process.ex | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/elixir/lib/process.ex b/lib/elixir/lib/process.ex
index 387f28463fd..c98cdce7b42 100644
--- a/lib/elixir/lib/process.ex
+++ b/lib/elixir/lib/process.ex
@@ -826,6 +826,9 @@ defmodule Process do
   @spec flag(pid, :save_calls, 0..10000) :: 0..10000
   defdelegate flag(pid, flag, value), to: :erlang, as: :process_flag
 
+  @type process_info_item :: atom | {:dictionary, term}
+  @type process_info_result_item :: {process_info_item, term}
+
   @doc """
   Returns information about the process identified by `pid`, or returns `nil` if the process
   is not alive.
@@ -834,7 +837,7 @@ defmodule Process do
 
   See `:erlang.process_info/1` for more information.
   """
-  @spec info(pid) :: keyword | nil
+  @spec info(pid) :: [process_info_result_item] | nil
   def info(pid) do
     nilify(:erlang.process_info(pid))
   end
@@ -845,7 +848,8 @@ defmodule Process do
 
   See `:erlang.process_info/2` for more information.
   """
-  @spec info(pid, atom | [atom]) :: {atom, term} | [{atom, term}] | nil
+  @spec info(pid, process_info_item | [process_info_item]) ::
+          process_info_result_item | [process_info_result_item] | nil
   def info(pid, spec)
 
   def info(pid, :registered_name) do
@@ -856,6 +860,10 @@ defmodule Process do
     end
   end
 
+  def info(pid, {:dictionary, key}) do
+    nilify(:erlang.process_info(pid, {:dictionary, key}))
+  end
+
   def info(pid, spec) when is_atom(spec) or is_list(spec) do
     nilify(:erlang.process_info(pid, spec))
   end

From 7c9e2dc6cf28c7efd166995aa9321abc911de07d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20=C5=81=C4=99picki?=
 <michallepicki@users.noreply.github.com>
Date: Mon, 22 Apr 2024 21:28:04 +0200
Subject: [PATCH 2/4] Revert the change to info/1 spec

---
 lib/elixir/lib/process.ex | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/elixir/lib/process.ex b/lib/elixir/lib/process.ex
index c98cdce7b42..8a58d24719e 100644
--- a/lib/elixir/lib/process.ex
+++ b/lib/elixir/lib/process.ex
@@ -826,9 +826,6 @@ defmodule Process do
   @spec flag(pid, :save_calls, 0..10000) :: 0..10000
   defdelegate flag(pid, flag, value), to: :erlang, as: :process_flag
 
-  @type process_info_item :: atom | {:dictionary, term}
-  @type process_info_result_item :: {process_info_item, term}
-
   @doc """
   Returns information about the process identified by `pid`, or returns `nil` if the process
   is not alive.
@@ -837,11 +834,14 @@ defmodule Process do
 
   See `:erlang.process_info/1` for more information.
   """
-  @spec info(pid) :: [process_info_result_item] | nil
+  @spec info(pid) :: keyword | nil
   def info(pid) do
     nilify(:erlang.process_info(pid))
   end
 
+  @type process_info_item :: atom | {:dictionary, term}
+  @type process_info_result_item :: {process_info_item, term}
+
   @doc """
   Returns information about the process identified by `pid`,
   or returns `nil` if the process is not alive.

From 16ae690c569171a2999352855442967c9f2a1d93 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20=C5=81=C4=99picki?=
 <michallepicki@users.noreply.github.com>
Date: Mon, 22 Apr 2024 21:29:13 +0200
Subject: [PATCH 3/4] Remove guard from Process.info/2

We can rely on better ArgumentError messages on newer OTP
---
 lib/elixir/lib/process.ex | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/lib/elixir/lib/process.ex b/lib/elixir/lib/process.ex
index 8a58d24719e..5fdba8bf36e 100644
--- a/lib/elixir/lib/process.ex
+++ b/lib/elixir/lib/process.ex
@@ -860,11 +860,7 @@ defmodule Process do
     end
   end
 
-  def info(pid, {:dictionary, key}) do
-    nilify(:erlang.process_info(pid, {:dictionary, key}))
-  end
-
-  def info(pid, spec) when is_atom(spec) or is_list(spec) do
+  def info(pid, spec) do
     nilify(:erlang.process_info(pid, spec))
   end
 

From 03549370cea2af326e05ab6fb84d0eecd1379480 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20=C5=81=C4=99picki?=
 <michallepicki@users.noreply.github.com>
Date: Mon, 22 Apr 2024 22:21:16 +0200
Subject: [PATCH 4/4] Improve Process.info/2 spec by defining it for two non
 overlaping clauses

---
 lib/elixir/lib/process.ex | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/elixir/lib/process.ex b/lib/elixir/lib/process.ex
index 5fdba8bf36e..387a52a727a 100644
--- a/lib/elixir/lib/process.ex
+++ b/lib/elixir/lib/process.ex
@@ -848,8 +848,8 @@ defmodule Process do
 
   See `:erlang.process_info/2` for more information.
   """
-  @spec info(pid, process_info_item | [process_info_item]) ::
-          process_info_result_item | [process_info_result_item] | nil
+  @spec info(pid, process_info_item) :: process_info_result_item | nil
+  @spec info(pid, [process_info_item]) :: [process_info_result_item] | nil
   def info(pid, spec)
 
   def info(pid, :registered_name) do