Print formatted file names in mix format --verbose, add --verbose flag

Author: georgeguimaraes

lib/mix/lib/mix/tasks/format.ex

@@ -77,6 +77,8 @@ defmodule Mix.Tasks.Format do
 
     * `--dry-run` - does not save files after formatting.
 
+    * `--verbose` - prints the names of files that were formatted.
+
     * `--dot-formatter` - path to the file with formatter configuration.
       Defaults to `.formatter.exs` if one is available. See the
       "Formatting options" section above for more information.
@@ -199,6 +201,7 @@ defmodule Mix.Tasks.Format do
     no_exit: :boolean,
     dot_formatter: :string,
     dry_run: :boolean,
+    verbose: :boolean,
     stdin_filename: :string,
     force: :boolean,
     migrate: :boolean
@@ -264,7 +267,7 @@ defmodule Mix.Tasks.Format do
     maybe_cache_timestamps(all_args, files, fn files ->
       files
       |> Task.async_stream(&format_file(&1, opts), ordered: false, timeout: :infinity)
-      |> Enum.reduce({[], []}, &collect_status/2)
+      |> Enum.reduce({[], [], []}, &collect_status/2)
       |> check!(opts)
     end)
   end
@@ -773,39 +776,64 @@ defmodule Mix.Tasks.Format do
 
   defp write_or_print(file, input, output) do
     cond do
-      file == :stdin -> IO.write(output)
-      input == output -> :ok
-      true -> File.write!(file, output)
-    end
+      file == :stdin ->
+        IO.write(output)
+        :ok
 
-    :ok
+      input == output ->
+        :ok
+
+      true ->
+        File.write!(file, output)
+        {:formatted, file}
+    end
   end
 
   defp collect_status({:ok, :ok}, acc), do: acc
 
-  defp collect_status({:ok, {:exit, _, _, _} = exit}, {exits, not_formatted}) do
-    {[exit | exits], not_formatted}
+  defp collect_status({:ok, {:exit, _, _, _} = exit}, {exits, not_formatted, formatted}) do
+    {[exit | exits], not_formatted, formatted}
   end
 
-  defp collect_status({:ok, {:not_formatted, file}}, {exits, not_formatted}) do
-    {exits, [file | not_formatted]}
+  defp collect_status({:ok, {:not_formatted, file}}, {exits, not_formatted, formatted}) do
+    {exits, [file | not_formatted], formatted}
   end
 
-  defp check!({[], []}, _task_opts) do
+  defp collect_status({:ok, {:formatted, file}}, {exits, not_formatted, formatted}) do
+    {exits, not_formatted, [file | formatted]}
+  end
+
+  defp check!({[], [], []}, _task_opts) do
+    :ok
+  end
+
+  defp check!({[], [], formatted}, task_opts) do
+    if task_opts[:verbose] do
+      formatted
+      |> Enum.sort()
+      |> Enum.each(&Mix.shell().info([:green, "* formatting ", :reset, Path.relative_to_cwd(&1)]))
+    end
+
     :ok
   end
 
-  defp check!({[{:exit, :stdin, exception, stacktrace} | _], _not_formatted}, _task_opts) do
+  defp check!(
+         {[{:exit, :stdin, exception, stacktrace} | _], _not_formatted, _formatted},
+         _task_opts
+       ) do
     Mix.shell().error("mix format failed for stdin")
     reraise exception, stacktrace
   end
 
-  defp check!({[{:exit, file, exception, stacktrace} | _], _not_formatted}, _task_opts) do
+  defp check!(
+         {[{:exit, file, exception, stacktrace} | _], _not_formatted, _formatted},
+         _task_opts
+       ) do
     Mix.shell().error("mix format failed for file: #{Path.relative_to_cwd(file)}")
     reraise exception, stacktrace
   end
 
-  defp check!({_exits, [_ | _] = not_formatted}, task_opts) do
+  defp check!({_exits, [_ | _] = not_formatted, _formatted}, task_opts) do
     no_exit? = Keyword.get(task_opts, :no_exit, false)
 
     message = """

lib/mix/test/mix/tasks/format_test.exs

@@ -85,6 +85,35 @@ defmodule Mix.Tasks.FormatTest do
     end)
   end
 
+  test "prints formatted file names with --verbose", context do
+    in_tmp(context.test, fn ->
+      File.write!("a.ex", """
+      foo bar
+      """)
+
+      File.write!("b.ex", """
+      foo(bar)
+      """)
+
+      Mix.Tasks.Format.run(["a.ex", "b.ex", "--verbose"])
+
+      assert_received {:mix_shell, :info, ["* formatting a.ex"]}
+      refute_received {:mix_shell, :info, ["* formatting b.ex"]}
+    end)
+  end
+
+  test "does not print formatted file names by default", context do
+    in_tmp(context.test, fn ->
+      File.write!("a.ex", """
+      foo bar
+      """)
+
+      Mix.Tasks.Format.run(["a.ex"])
+
+      refute_received {:mix_shell, :info, ["* formatting a.ex"]}
+    end)
+  end
+
   test "does not try to format a directory that matches a given pattern", context do
     in_tmp(context.test, fn ->
       File.mkdir_p!("a.ex")