From b55888befd96080043854f78839435b6e88bd1f7 Mon Sep 17 00:00:00 2001
From: Eksperimental <eksperimental@autistici.org>
Date: Wed, 25 Mar 2026 10:30:59 -0500
Subject: [PATCH 1/3] Improve function argument naming, specs and guards in Mix

---
 lib/mix/lib/mix.ex | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/lib/mix/lib/mix.ex b/lib/mix/lib/mix.ex
index 9f0e0c65155..5498157bfe4 100644
--- a/lib/mix/lib/mix.ex
+++ b/lib/mix/lib/mix.ex
@@ -452,6 +452,7 @@ defmodule Mix do
   import Kernel, except: [raise: 2]
 
   @doc false
+  @spec start() :: :ok
   def start do
     {:ok, _} = Application.ensure_all_started(:mix)
     :ok
@@ -485,7 +486,7 @@ defmodule Mix do
   Proper configuration can be set in config files, often per-environment
   (see the `Config` module for more information).
   """
-  @spec env() :: atom()
+  @spec env() :: env :: atom()
   def env do
     # env is not available on bootstrapping, so set a :dev default
     Mix.State.get(:env, :dev)
@@ -508,7 +509,7 @@ defmodule Mix do
   @doc """
   Returns the Mix target.
   """
-  @spec target() :: atom()
+  @spec target() :: target :: atom()
   def target do
     # target is not available on bootstrapping, so set a :host default
     Mix.State.get(:target, :host)
@@ -536,7 +537,7 @@ defmodule Mix do
       end
 
   """
-  @spec compilers() :: [atom()]
+  @spec compilers() :: [compiler :: atom()]
   def compilers do
     [:erlang, :elixir, :app]
   end
@@ -612,8 +613,8 @@ defmodule Mix do
   Sets Mix debug mode.
   """
   @spec debug(boolean()) :: :ok
-  def debug(debug) when is_boolean(debug) do
-    Mix.State.put(:debug, debug)
+  def debug(enabled?) when is_boolean(enabled?) do
+    Mix.State.put(:debug, enabled?)
   end
 
   @doc """
@@ -651,7 +652,9 @@ defmodule Mix do
   The path for local archives or escripts.
   """
   @doc since: "1.10.0"
-  @spec path_for(:archives | :escripts) :: String.t()
+  @spec path_for(kind :: :archives | :escripts) :: String.t()
+  def path_for(kind)
+
   def path_for(:archives) do
     System.get_env("MIX_ARCHIVES") || Path.join(Mix.Utils.mix_home(), "archives")
   end
@@ -671,6 +674,7 @@ defmodule Mix do
   This function does not start the given applications.
   """
   @doc since: "1.15.0"
+  @spec ensure_application!(Application.app()) :: :ok
   def ensure_application!(app) when is_atom(app) do
     ensure_application!(app, Mix.State.builtin_apps(), [], %{})
     :ok
@@ -1131,7 +1135,7 @@ defmodule Mix do
   end
 
   @doc false
-  def in_install_project(fun) do
+  def in_install_project(fun) when is_function(fun, 0) do
     case safe_get_installed() do
       {id, dynamic_config} ->
         config = install_project_config(dynamic_config)
@@ -1221,5 +1225,6 @@ defmodule Mix do
   end
 
   @doc false
+  @spec install?() :: boolean()
   def install?, do: Mix.Project.get() == @mix_install_project
 end

From a060c9939d474e7309e2555c4845f10640801142 Mon Sep 17 00:00:00 2001
From: Eksperimental <eksperimental@autistici.org>
Date: Wed, 25 Mar 2026 16:25:17 -0500
Subject: [PATCH 2/3] Apply suggestions by @josevalim

---
 lib/mix/lib/mix.ex | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/lib/mix/lib/mix.ex b/lib/mix/lib/mix.ex
index 5498157bfe4..0fbf441b67e 100644
--- a/lib/mix/lib/mix.ex
+++ b/lib/mix/lib/mix.ex
@@ -452,7 +452,6 @@ defmodule Mix do
   import Kernel, except: [raise: 2]
 
   @doc false
-  @spec start() :: :ok
   def start do
     {:ok, _} = Application.ensure_all_started(:mix)
     :ok
@@ -486,7 +485,7 @@ defmodule Mix do
   Proper configuration can be set in config files, often per-environment
   (see the `Config` module for more information).
   """
-  @spec env() :: env :: atom()
+  @spec env() :: atom()
   def env do
     # env is not available on bootstrapping, so set a :dev default
     Mix.State.get(:env, :dev)
@@ -509,7 +508,7 @@ defmodule Mix do
   @doc """
   Returns the Mix target.
   """
-  @spec target() :: target :: atom()
+  @spec target() :: atom()
   def target do
     # target is not available on bootstrapping, so set a :host default
     Mix.State.get(:target, :host)
@@ -652,7 +651,7 @@ defmodule Mix do
   The path for local archives or escripts.
   """
   @doc since: "1.10.0"
-  @spec path_for(kind :: :archives | :escripts) :: String.t()
+  @spec path_for(:archives | :escripts) :: String.t()
   def path_for(kind)
 
   def path_for(:archives) do
@@ -1225,6 +1224,5 @@ defmodule Mix do
   end
 
   @doc false
-  @spec install?() :: boolean()
   def install?, do: Mix.Project.get() == @mix_install_project
 end

From 84b35913e7e77fc9457c0e981d85dfbd451a6080 Mon Sep 17 00:00:00 2001
From: Eksperimental <eksperimental@autistici.org>
Date: Thu, 26 Mar 2026 06:08:56 -0500
Subject: [PATCH 3/3] Update lib/mix/lib/mix.ex
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: José Valim <jose.valim@gmail.com>
---
 lib/mix/lib/mix.ex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/mix/lib/mix.ex b/lib/mix/lib/mix.ex
index 0fbf441b67e..c7083f9b55b 100644
--- a/lib/mix/lib/mix.ex
+++ b/lib/mix/lib/mix.ex
@@ -536,7 +536,7 @@ defmodule Mix do
       end
 
   """
-  @spec compilers() :: [compiler :: atom()]
+  @spec compilers() :: [atom()]
   def compilers do
     [:erlang, :elixir, :app]
   end