From 5ebda57ed4afdc68dff43b24f62c1d1e72776478 Mon Sep 17 00:00:00 2001
From: Maarten van Vliet <maartenvanvliet@gmail.com>
Date: Tue, 26 Oct 2021 09:42:34 +0200
Subject: [PATCH 1/6] Pass sigil/modifiers through to formatter

This allows the formatter plugins to format content
based on whether it's a file or a sigil being formatted.
The modifiers could be used for additional options.
---
 lib/elixir/lib/code/formatter.ex              |  6 ++---
 .../elixir/code_formatter/general_test.exs    | 24 +++++++++++++++----
 lib/mix/lib/mix/tasks/format.ex               |  2 +-
 lib/mix/test/mix/tasks/format_test.exs        | 19 +++++++++++++--
 4 files changed, 41 insertions(+), 10 deletions(-)

diff --git a/lib/elixir/lib/code/formatter.ex b/lib/elixir/lib/code/formatter.ex
index 635d41f8968..277371466a9 100644
--- a/lib/elixir/lib/code/formatter.ex
+++ b/lib/elixir/lib/code/formatter.ex
@@ -181,7 +181,7 @@ defmodule Code.Formatter do
 
     sigils =
       Map.new(sigils, fn {key, value} ->
-        with true <- is_atom(key) and is_function(value, 1),
+        with true <- is_atom(key) and is_function(value, 2),
              [char] <- Atom.to_charlist(key),
              true <- char in ?A..?Z do
           {char, value}
@@ -189,7 +189,7 @@ defmodule Code.Formatter do
           _ ->
             raise ArgumentError,
                   ":sigils must be a keyword list with a single uppercased letter as key and an " <>
-                    "anonymous function expecting a single argument as value, got: #{inspect(sigils)}"
+                    "anonymous function expecting two arguments as value, got: #{inspect(sigils)}"
         end
       end)
 
@@ -1320,7 +1320,7 @@ defmodule Code.Formatter do
       entries =
         case state.sigils do
           %{^name => callback} ->
-            case callback.(hd(entries)) do
+            case callback.(hd(entries), sigil: {List.to_atom([name]), List.to_string(modifiers)}) do
               binary when is_binary(binary) ->
                 [binary]
 
diff --git a/lib/elixir/test/elixir/code_formatter/general_test.exs b/lib/elixir/test/elixir/code_formatter/general_test.exs
index 9559087fbac..76149b64725 100644
--- a/lib/elixir/test/elixir/code_formatter/general_test.exs
+++ b/lib/elixir/test/elixir/code_formatter/general_test.exs
@@ -125,7 +125,11 @@ defmodule Code.Formatter.GeneralTest do
       ~W/foo bar baz/
       """
 
-      formatter = &(&1 |> String.split(~r/ +/) |> Enum.join(" "))
+      formatter = fn content, opts ->
+        assert opts == [sigil: {:W, ""}]
+        content |> String.split(~r/ +/) |> Enum.join(" ")
+      end
+
       assert_format bad, good, sigils: [W: formatter]
 
       bad = """
@@ -136,7 +140,11 @@ defmodule Code.Formatter.GeneralTest do
       var = ~W/foo bar baz/abc
       """
 
-      formatter = &(&1 |> String.split(~r/ +/) |> Enum.join(" "))
+      formatter = fn content, opts ->
+        assert opts == [sigil: {:W, "abc"}]
+        content |> String.split(~r/ +/) |> Enum.join(" ")
+      end
+
       assert_format bad, good, sigils: [W: formatter]
     end
 
@@ -153,7 +161,11 @@ defmodule Code.Formatter.GeneralTest do
       '''
       """
 
-      formatter = &(&1 |> String.split(~r/ +/) |> Enum.join(" "))
+      formatter = fn content, opts ->
+        assert opts == [sigil: {:W, ""}]
+        content |> String.split(~r/ +/) |> Enum.join(" ")
+      end
+
       assert_format bad, good, sigils: [W: formatter]
 
       bad = """
@@ -176,7 +188,11 @@ defmodule Code.Formatter.GeneralTest do
       end
       """
 
-      formatter = &(&1 |> String.split(~r/ +/) |> Enum.join("\n"))
+      formatter = fn content, opts ->
+        assert opts == [sigil: {:W, "abc"}]
+        content |> String.split(~r/ +/) |> Enum.join("\n")
+      end
+
       assert_format bad, good, sigils: [W: formatter]
     end
   end
diff --git a/lib/mix/lib/mix/tasks/format.ex b/lib/mix/lib/mix/tasks/format.ex
index 1fd5722ccae..bb065f3cd13 100644
--- a/lib/mix/lib/mix/tasks/format.ex
+++ b/lib/mix/lib/mix/tasks/format.ex
@@ -531,7 +531,7 @@ defmodule Mix.Tasks.Format do
     sigils =
       for plugin <- Keyword.fetch!(formatter_opts, :plugins),
           sigil <- find_sigils_from_plugins(plugin, formatter_opts),
-          do: {sigil, &plugin.format(&1, formatter_opts)}
+          do: {sigil, &plugin.format(&1, &2 ++ formatter_opts)}
 
     IO.iodata_to_binary([Code.format_string!(content, [sigils: sigils] ++ formatter_opts), ?\n])
   end
diff --git a/lib/mix/test/mix/tasks/format_test.exs b/lib/mix/test/mix/tasks/format_test.exs
index aacb19f128f..d7912d05c5d 100644
--- a/lib/mix/test/mix/tasks/format_test.exs
+++ b/lib/mix/test/mix/tasks/format_test.exs
@@ -199,11 +199,12 @@ defmodule Mix.Tasks.FormatTest do
 
     def features(opts) do
       assert opts[:from_formatter_exs] == :yes
-      [sigils: [:W], extensions: ~w(.w)]
+      [sigils: [:W]]
     end
 
     def format(contents, opts) do
       assert opts[:from_formatter_exs] == :yes
+      assert opts[:sigil] == {:W, "abc"}
       contents |> String.split(~r/\s/) |> Enum.join("\n")
     end
   end
@@ -240,12 +241,26 @@ defmodule Mix.Tasks.FormatTest do
     end)
   end
 
+  defmodule Elixir.ExtensionWPlugin do
+    @behaviour Mix.Tasks.Format
+
+    def features(opts) do
+      assert opts[:from_formatter_exs] == :yes
+      [extensions: ~w(.w)]
+    end
+
+    def format(contents, opts) do
+      assert opts[:from_formatter_exs] == :yes
+      contents |> String.split(~r/\s/) |> Enum.join("\n")
+    end
+  end
+
   test "uses extension plugins from .formatter.exs", context do
     in_tmp(context.test, fn ->
       File.write!(".formatter.exs", """
       [
         inputs: ["a.w"],
-        plugins: [SigilWPlugin],
+        plugins: [ExtensionWPlugin],
         from_formatter_exs: :yes
       ]
       """)

From f01ff068d59eb8c04a61556d0175b87dae28d5c3 Mon Sep 17 00:00:00 2001
From: Maarten van Vliet <maartenvanvliet@gmail.com>
Date: Tue, 26 Oct 2021 11:21:44 +0200
Subject: [PATCH 2/6] Pass sigil modifiers as charlist

---
 lib/elixir/lib/code/formatter.ex                       | 2 +-
 lib/elixir/test/elixir/code_formatter/general_test.exs | 8 ++++----
 lib/mix/test/mix/tasks/format_test.exs                 | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/elixir/lib/code/formatter.ex b/lib/elixir/lib/code/formatter.ex
index 277371466a9..43ea84ffda1 100644
--- a/lib/elixir/lib/code/formatter.ex
+++ b/lib/elixir/lib/code/formatter.ex
@@ -1320,7 +1320,7 @@ defmodule Code.Formatter do
       entries =
         case state.sigils do
           %{^name => callback} ->
-            case callback.(hd(entries), sigil: {List.to_atom([name]), List.to_string(modifiers)}) do
+            case callback.(hd(entries), sigil: {List.to_atom([name]), modifiers}) do
               binary when is_binary(binary) ->
                 [binary]
 
diff --git a/lib/elixir/test/elixir/code_formatter/general_test.exs b/lib/elixir/test/elixir/code_formatter/general_test.exs
index 76149b64725..ce84923cc37 100644
--- a/lib/elixir/test/elixir/code_formatter/general_test.exs
+++ b/lib/elixir/test/elixir/code_formatter/general_test.exs
@@ -126,7 +126,7 @@ defmodule Code.Formatter.GeneralTest do
       """
 
       formatter = fn content, opts ->
-        assert opts == [sigil: {:W, ""}]
+        assert opts == [sigil: {:W, []}]
         content |> String.split(~r/ +/) |> Enum.join(" ")
       end
 
@@ -141,7 +141,7 @@ defmodule Code.Formatter.GeneralTest do
       """
 
       formatter = fn content, opts ->
-        assert opts == [sigil: {:W, "abc"}]
+        assert opts == [sigil: {:W, 'abc'}]
         content |> String.split(~r/ +/) |> Enum.join(" ")
       end
 
@@ -162,7 +162,7 @@ defmodule Code.Formatter.GeneralTest do
       """
 
       formatter = fn content, opts ->
-        assert opts == [sigil: {:W, ""}]
+        assert opts == [sigil: {:W, []}]
         content |> String.split(~r/ +/) |> Enum.join(" ")
       end
 
@@ -189,7 +189,7 @@ defmodule Code.Formatter.GeneralTest do
       """
 
       formatter = fn content, opts ->
-        assert opts == [sigil: {:W, "abc"}]
+        assert opts == [sigil: {:W, 'abc'}]
         content |> String.split(~r/ +/) |> Enum.join("\n")
       end
 
diff --git a/lib/mix/test/mix/tasks/format_test.exs b/lib/mix/test/mix/tasks/format_test.exs
index d7912d05c5d..43a8de8c97b 100644
--- a/lib/mix/test/mix/tasks/format_test.exs
+++ b/lib/mix/test/mix/tasks/format_test.exs
@@ -204,7 +204,7 @@ defmodule Mix.Tasks.FormatTest do
 
     def format(contents, opts) do
       assert opts[:from_formatter_exs] == :yes
-      assert opts[:sigil] == {:W, "abc"}
+      assert opts[:sigil] == {:W, 'abc'}
       contents |> String.split(~r/\s/) |> Enum.join("\n")
     end
   end

From 96c4f9bf416920e8e20cb5e86d447bab70a1f629 Mon Sep 17 00:00:00 2001
From: Maarten van Vliet <maartenvanvliet@gmail.com>
Date: Tue, 26 Oct 2021 11:45:56 +0200
Subject: [PATCH 3/6] Pass through file extension to formatter plugins

---
 lib/mix/lib/mix/tasks/format.ex        | 2 +-
 lib/mix/test/mix/tasks/format_test.exs | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/mix/lib/mix/tasks/format.ex b/lib/mix/lib/mix/tasks/format.ex
index bb065f3cd13..c3bd5ed803b 100644
--- a/lib/mix/lib/mix/tasks/format.ex
+++ b/lib/mix/lib/mix/tasks/format.ex
@@ -490,7 +490,7 @@ defmodule Mix.Tasks.Format do
         &elixir_format(&1, [file: file] ++ formatter_opts)
 
       plugin = find_plugin_for_extension(formatter_opts, ext) ->
-        &plugin.format(&1, formatter_opts)
+        &plugin.format(&1, [extension: Path.extname(file)] ++ formatter_opts)
 
       true ->
         & &1
diff --git a/lib/mix/test/mix/tasks/format_test.exs b/lib/mix/test/mix/tasks/format_test.exs
index 43a8de8c97b..17450c1f63a 100644
--- a/lib/mix/test/mix/tasks/format_test.exs
+++ b/lib/mix/test/mix/tasks/format_test.exs
@@ -251,6 +251,7 @@ defmodule Mix.Tasks.FormatTest do
 
     def format(contents, opts) do
       assert opts[:from_formatter_exs] == :yes
+      assert opts[:extension] == ".w"
       contents |> String.split(~r/\s/) |> Enum.join("\n")
     end
   end

From b2cfddec830985be0216ef3c3ede9e4abcaf2bca Mon Sep 17 00:00:00 2001
From: Maarten van Vliet <maartenvanvliet@gmail.com>
Date: Tue, 26 Oct 2021 12:56:54 +0200
Subject: [PATCH 4/6] Add documentation sigil/extensions in format plugin

---
 lib/elixir/lib/code.ex          | 6 ++++++
 lib/mix/lib/mix/tasks/format.ex | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/lib/elixir/lib/code.ex b/lib/elixir/lib/code.ex
index 98eabf23fb4..1c118498817 100644
--- a/lib/elixir/lib/code.ex
+++ b/lib/elixir/lib/code.ex
@@ -437,6 +437,12 @@ defmodule Code do
       If you set it to `false` later on, `do`-`end` blocks won't be
       converted back to keywords.
 
+    * `:extension` (since v1.13.0) - extension of the file. Used by
+      formatter plugins.
+
+    * `:sigil` (since v1.13.0) - a tuple of the sigil and its modifiers.
+      Used by formatter plugins.
+
   ## Design principles
 
   The formatter was designed under three principles.
diff --git a/lib/mix/lib/mix/tasks/format.ex b/lib/mix/lib/mix/tasks/format.ex
index c3bd5ed803b..244769596f9 100644
--- a/lib/mix/lib/mix/tasks/format.ex
+++ b/lib/mix/lib/mix/tasks/format.ex
@@ -102,6 +102,13 @@ defmodule Mix.Tasks.Format do
         end
       end
 
+  The `opts` passed to `format/2` contains all the formatting options and either:
+
+      * `:sigil` (tuple of sigil and its modifiers) - the sigil being formatted,
+        e.g. `{:M, []}`.
+
+      * `:extension` (string) - the extension of the file being formatted, e.g. `".md"`.
+
   Now any application can use your formatter as follows:
 
       # .formatters.exs

From ab815861664be401241fe6c907c4f7c5ca993e3b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@gmail.com>
Date: Tue, 26 Oct 2021 13:36:00 +0200
Subject: [PATCH 5/6] Apply suggestions from code review

---
 lib/elixir/lib/code.ex          | 6 ------
 lib/mix/lib/mix/tasks/format.ex | 2 +-
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/lib/elixir/lib/code.ex b/lib/elixir/lib/code.ex
index 1c118498817..98eabf23fb4 100644
--- a/lib/elixir/lib/code.ex
+++ b/lib/elixir/lib/code.ex
@@ -437,12 +437,6 @@ defmodule Code do
       If you set it to `false` later on, `do`-`end` blocks won't be
       converted back to keywords.
 
-    * `:extension` (since v1.13.0) - extension of the file. Used by
-      formatter plugins.
-
-    * `:sigil` (since v1.13.0) - a tuple of the sigil and its modifiers.
-      Used by formatter plugins.
-
   ## Design principles
 
   The formatter was designed under three principles.
diff --git a/lib/mix/lib/mix/tasks/format.ex b/lib/mix/lib/mix/tasks/format.ex
index 244769596f9..cda8f880182 100644
--- a/lib/mix/lib/mix/tasks/format.ex
+++ b/lib/mix/lib/mix/tasks/format.ex
@@ -497,7 +497,7 @@ defmodule Mix.Tasks.Format do
         &elixir_format(&1, [file: file] ++ formatter_opts)
 
       plugin = find_plugin_for_extension(formatter_opts, ext) ->
-        &plugin.format(&1, [extension: Path.extname(file)] ++ formatter_opts)
+        &plugin.format(&1, [extension: ext] ++ formatter_opts)
 
       true ->
         & &1

From 6766172a39532e42a4715df6e7b7b0e071c5459d Mon Sep 17 00:00:00 2001
From: Maarten van Vliet <maartenvanvliet@gmail.com>
Date: Tue, 26 Oct 2021 13:56:12 +0200
Subject: [PATCH 6/6] Pass modifiers separately

---
 lib/elixir/lib/code/formatter.ex                       | 2 +-
 lib/elixir/test/elixir/code_formatter/general_test.exs | 8 ++++----
 lib/mix/lib/mix/tasks/format.ex                        | 5 +++--
 lib/mix/test/mix/tasks/format_test.exs                 | 3 ++-
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/lib/elixir/lib/code/formatter.ex b/lib/elixir/lib/code/formatter.ex
index 43ea84ffda1..7c0dd8bda31 100644
--- a/lib/elixir/lib/code/formatter.ex
+++ b/lib/elixir/lib/code/formatter.ex
@@ -1320,7 +1320,7 @@ defmodule Code.Formatter do
       entries =
         case state.sigils do
           %{^name => callback} ->
-            case callback.(hd(entries), sigil: {List.to_atom([name]), modifiers}) do
+            case callback.(hd(entries), sigil: List.to_atom([name]), modifiers: modifiers) do
               binary when is_binary(binary) ->
                 [binary]
 
diff --git a/lib/elixir/test/elixir/code_formatter/general_test.exs b/lib/elixir/test/elixir/code_formatter/general_test.exs
index ce84923cc37..5aed5d17cec 100644
--- a/lib/elixir/test/elixir/code_formatter/general_test.exs
+++ b/lib/elixir/test/elixir/code_formatter/general_test.exs
@@ -126,7 +126,7 @@ defmodule Code.Formatter.GeneralTest do
       """
 
       formatter = fn content, opts ->
-        assert opts == [sigil: {:W, []}]
+        assert opts == [sigil: :W, modifiers: []]
         content |> String.split(~r/ +/) |> Enum.join(" ")
       end
 
@@ -141,7 +141,7 @@ defmodule Code.Formatter.GeneralTest do
       """
 
       formatter = fn content, opts ->
-        assert opts == [sigil: {:W, 'abc'}]
+        assert opts == [sigil: :W, modifiers: 'abc']
         content |> String.split(~r/ +/) |> Enum.join(" ")
       end
 
@@ -162,7 +162,7 @@ defmodule Code.Formatter.GeneralTest do
       """
 
       formatter = fn content, opts ->
-        assert opts == [sigil: {:W, []}]
+        assert opts == [sigil: :W, modifiers: []]
         content |> String.split(~r/ +/) |> Enum.join(" ")
       end
 
@@ -189,7 +189,7 @@ defmodule Code.Formatter.GeneralTest do
       """
 
       formatter = fn content, opts ->
-        assert opts == [sigil: {:W, 'abc'}]
+        assert opts == [sigil: :W, modifiers: 'abc']
         content |> String.split(~r/ +/) |> Enum.join("\n")
       end
 
diff --git a/lib/mix/lib/mix/tasks/format.ex b/lib/mix/lib/mix/tasks/format.ex
index cda8f880182..b9e7f6c9a8b 100644
--- a/lib/mix/lib/mix/tasks/format.ex
+++ b/lib/mix/lib/mix/tasks/format.ex
@@ -104,8 +104,9 @@ defmodule Mix.Tasks.Format do
 
   The `opts` passed to `format/2` contains all the formatting options and either:
 
-      * `:sigil` (tuple of sigil and its modifiers) - the sigil being formatted,
-        e.g. `{:M, []}`.
+      * `:sigil` (atom) - the sigil being formatted, e.g. `:M`.
+
+      * `:modifiers` (charlist) - list of sigil modifiers.
 
       * `:extension` (string) - the extension of the file being formatted, e.g. `".md"`.
 
diff --git a/lib/mix/test/mix/tasks/format_test.exs b/lib/mix/test/mix/tasks/format_test.exs
index 17450c1f63a..6473cfd4a71 100644
--- a/lib/mix/test/mix/tasks/format_test.exs
+++ b/lib/mix/test/mix/tasks/format_test.exs
@@ -204,7 +204,8 @@ defmodule Mix.Tasks.FormatTest do
 
     def format(contents, opts) do
       assert opts[:from_formatter_exs] == :yes
-      assert opts[:sigil] == {:W, 'abc'}
+      assert opts[:sigil] == :W
+      assert opts[:modifiers] == 'abc'
       contents |> String.split(~r/\s/) |> Enum.join("\n")
     end
   end