fix(build): inline dep-patch logic into mix.exs so it runs during deps.get

Previously the `mix deps.patch` task lived at `lib/mix/tasks/deps.patch.ex`
and the `deps.get` alias invoked it. This broke `mix deps.get --only prod`
in Docker: `lib/` isn't compiled yet when deps are fetched, so the task
module couldn't be resolved and the build failed with
`The task "deps.patch" could not be found`.

Move the patch-application function directly into `mix.exs` as a private
helper and wire it into the alias via `&apply_dep_patches/1`. `mix.exs` is
always loadable, so the function is available the moment `deps.get` runs.

lib/mix/tasks/deps.patch.ex

@@ -1,77 +0,0 @@
-defmodule Mix.Tasks.Deps.Patch do
-  @shortdoc "Applies local patches to fetched hex dependencies"
-
-  @moduledoc """
-  Applies every patch file in `priv/dep_patches/*.patch` to its
-  corresponding dependency under `deps/`. Each patch name follows the
-  convention `<dep_name>-<version>.patch` (e.g. `live_table-0.4.1.patch`).
-
-  Applied idempotently — if the patched text is already present we skip
-  the dep. Run after `mix deps.get` / `mix deps.compile`. Safe to invoke
-  repeatedly.
-
-  Why this exists: `live_table` 0.4.1 has a call to
-  `LiveTable.LiveSelectHelpers.restore_live_select_from_params/2` whose
-  return value is discarded inside the macro-expanded `handle_params/3`,
-  tripping the strict dialyzer `:unmatched_return` flag at every `use`
-  site. The patch adds an `_ =` binding. Upstream PR TODO — once merged
-  and released, drop both the patch and this task.
-  """
-  use Mix.Task
-
-  @patches_dir "priv/dep_patches"
-
-  @impl Mix.Task
-  def run(_args) do
-    case File.ls(@patches_dir) do
-      {:ok, entries} ->
-        patches = entries |> Enum.filter(&String.ends_with?(&1, ".patch")) |> Enum.sort()
-
-        Enum.each(patches, &apply_patch/1)
-
-      {:error, :enoent} ->
-        Mix.shell().info("deps.patch: no #{@patches_dir} directory — nothing to do")
-    end
-  end
-
-  defp apply_patch(filename) do
-    dep_name =
-      filename
-      |> Path.basename(".patch")
-      |> String.split("-")
-      |> Enum.drop(-1)
-      |> Enum.join("-")
-
-    dep_dir = Path.join("deps", dep_name)
-
-    cond do
-      not File.dir?(dep_dir) ->
-        Mix.shell().info("deps.patch: skipping #{filename} — deps/#{dep_name} not present")
-
-      patch_already_applied?(filename, dep_dir) ->
-        Mix.shell().info("deps.patch: #{filename} already applied")
-
-      true ->
-        patch_path = Path.join(@patches_dir, filename)
-        {output, exit_code} = System.cmd("patch", ["-p1", "-i", Path.absname(patch_path)], cd: dep_dir)
-
-        if exit_code == 0 do
-          Mix.shell().info("deps.patch: applied #{filename}")
-          touch_sentinel(filename, dep_dir)
-        else
-          Mix.raise("deps.patch: failed to apply #{filename}:\n#{output}")
-        end
-    end
-  end
-
-  # Record that the patch landed by writing a sentinel file inside the
-  # dep dir. `File.touch!/1` avoids spurious re-applications when the
-  # patch contains text the dep happens to contain already.
-  defp touch_sentinel(filename, dep_dir) do
-    File.touch!(Path.join(dep_dir, ".#{filename}.applied"))
-  end
-
-  defp patch_already_applied?(filename, dep_dir) do
-    File.exists?(Path.join(dep_dir, ".#{filename}.applied"))
-  end
-end

mix.exs

@@ -123,8 +123,8 @@ defmodule Microwaveprop.MixProject do
   # See the documentation for `Mix` for more info on aliases.
   defp aliases do
     [
-      setup: ["deps.get", "deps.patch", "ecto.setup", "assets.setup", "assets.build"],
+      setup: ["deps.get", "ecto.setup", "assets.setup", "assets.build"],
-      "deps.get": ["deps.get", "deps.patch"],
+      "deps.get": ["deps.get", &apply_dep_patches/1],
       "ecto.setup": ["ecto.create", "ecto.migrate", "run priv/repo/seeds.exs"],
       "ecto.reset": ["ecto.drop", "ecto.setup"],
       test: ["ecto.create --quiet", "ecto.migrate --quiet", "test"],
@@ -138,4 +138,55 @@ defmodule Microwaveprop.MixProject do
       precommit: ["compile --warnings-as-errors", "deps.unlock --unused", "format", "test"]
     ]
   end
+
+  # Applies every patch file in `priv/dep_patches/*.patch` to its corresponding
+  # dependency under `deps/`. Inlined here (instead of a `Mix.Task` module
+  # under `lib/mix/tasks/`) so it can run during `mix deps.get` itself —
+  # `lib/` isn't compiled yet at that point, so a proper task would not be
+  # resolvable. Idempotent: a sentinel file per patch prevents re-application.
+  @patches_dir "priv/dep_patches"
+
+  defp apply_dep_patches(_args) do
+    case File.ls(@patches_dir) do
+      {:ok, entries} ->
+        entries
+        |> Enum.filter(&String.ends_with?(&1, ".patch"))
+        |> Enum.sort()
+        |> Enum.each(&apply_single_patch/1)
+
+      {:error, :enoent} ->
+        :ok
+    end
+  end
+
+  defp apply_single_patch(filename) do
+    dep_name =
+      filename
+      |> Path.basename(".patch")
+      |> String.split("-")
+      |> Enum.drop(-1)
+      |> Enum.join("-")
+
+    dep_dir = Path.join("deps", dep_name)
+    sentinel = Path.join(dep_dir, ".#{filename}.applied")
+
+    cond do
+      not File.dir?(dep_dir) ->
+        Mix.shell().info("deps.patch: skipping #{filename} — deps/#{dep_name} not present")
+
+      File.exists?(sentinel) ->
+        Mix.shell().info("deps.patch: #{filename} already applied")
+
+      true ->
+        patch_path = Path.absname(Path.join(@patches_dir, filename))
+        {output, exit_code} = System.cmd("patch", ["-p1", "-i", patch_path], cd: dep_dir)
+
+        if exit_code == 0 do
+          Mix.shell().info("deps.patch: applied #{filename}")
+          File.touch!(sentinel)
+        else
+          Mix.raise("deps.patch: failed to apply #{filename}:\n#{output}")
+        end
+    end
+  end
 end