Allowing to ignore modules on Credo.Check.Readability.AliasAs

lib/credo/check/readability/alias_as.ex

@@ -2,6 +2,9 @@ defmodule Credo.Check.Readability.AliasAs do
   use Credo.Check,
     base_priority: :low,
     tags: [:experimental],
+    param_defaults: [
+      ignore: []
+    ],
     explanations: [
       check: """
       Aliases which are not completely renamed using the `:as` option are easier to follow.
@@ -30,29 +33,52 @@ defmodule Credo.Check.Readability.AliasAs do
       Like all `Readability` issues, this one is not a technical concern.
       But you can improve the odds of others reading and liking your code by making
       it easier to follow.
-      """
+      """,
+      params: [
+        ignore: "List of modules to ignore and allow to `alias Module, as: ...`"
+      ]
     ]
 
   @doc false
   @impl true
   def run(%SourceFile{} = source_file, params) do
+    ignore = Params.get(params, :ignore, __MODULE__)
+
     source_file
-    |> Credo.Code.prewalk(&traverse(&1, &2, IssueMeta.for(source_file, params)))
+    |> Credo.Code.prewalk(&traverse(&1, &2, IssueMeta.for(source_file, params), ignore))
     |> Enum.reverse()
   end
 
-  defp traverse(ast, issues, issue_meta), do: {ast, add_issue(issues, issue(ast, issue_meta))}
+  defp traverse(ast, issues, issue_meta, ignore),
+    do: {ast, add_issue(issues, issue(ast, issue_meta, ignore))}
 
   defp add_issue(issues, nil), do: issues
   defp add_issue(issues, issue), do: [issue | issues]
 
-  defp issue({:alias, _, [{:__MODULE__, _, nil}, [as: {_, meta, _}]]}, issue_meta),
-    do: issue_for(issue_meta, meta[:line], inspect(:__MODULE__))
+  defp issue({:alias, _, [{:__MODULE__, _, nil}, [as: {_, meta, _}]]}, issue_meta, ignore) do
+    line = meta[:line]
+    {Credo.IssueMeta, source_file, _check_params} = issue_meta
+    {_def, module_name} = Check.scope_for(source_file, line: line)
+    module = Module.concat([module_name])
+
+    if :__MODULE__ not in ignore and module not in ignore do
+      issue_for(issue_meta, line, inspect(:__MODULE__))
+    else
+      nil
+    end
+  end
 
-  defp issue({:alias, _, [{_, _, original}, [as: {_, meta, _}]]}, issue_meta),
-    do: issue_for(issue_meta, meta[:line], inspect(Module.concat(original)))
+  defp issue({:alias, _, [{_, _, original}, [as: {_, meta, _}]]}, issue_meta, ignore) do
+    module = Module.concat(original)
+
+    if module not in ignore do
+      issue_for(issue_meta, meta[:line], inspect(module))
+    else
+      nil
+    end
+  end
 
-  defp issue(_ast, _issue_meta), do: nil
+  defp issue(_ast, _issue_meta, _ignore), do: nil
 
   defp issue_for(issue_meta, line_no, trigger) do
     format_issue(

test/credo/check/readability/alias_as_test.exs

@@ -48,6 +48,39 @@ defmodule Credo.Check.Readability.AliasAsTest do
     assert issue3.trigger == "App.Module4"
   end
 
+  test "it should ignore violations for ignored modules" do
+    """
+    defmodule Test do
+      alias App.Module1, as: M1
+    end
+    """
+    |> to_source_file
+    |> run_check(@described_check, ignore: [App.Module1])
+    |> refute_issues()
+  end
+
+  test "it should ignore violations for __MODULE__ when :__MODULE__ is in ignore list" do
+    """
+    defmodule Test do
+      alias __MODULE__, as: Foo
+    end
+    """
+    |> to_source_file
+    |> run_check(@described_check, ignore: [:__MODULE__])
+    |> refute_issues()
+  end
+
+  test "it should ignore violations for __MODULE__ when the module is in ignore list" do
+    """
+    defmodule Test do
+      alias __MODULE__, as: Foo
+    end
+    """
+    |> to_source_file
+    |> run_check(@described_check, ignore: [Test])
+    |> refute_issues()
+  end
+
   test "it should not raise on alias __MODULE__, as: Foo" do
     _ =
       """