git stash save --keep-index の記述と実際の動作に相違あり？

[harupong]

There are a few stash variants that may also be helpful. The first option that is quite popular is the --keep-index option to the stash save command. This tells Git to not stash anything that you've already staged with the git add command.

v2で追加されたこの段落、「git stash save --keep-indexでstashすると、git addでインデックスに追加した内容はstashされないようにできる」という解釈で間違いないはず。けれど、このコマンドを実行すると、インデックスに追加されていた内容はstashされて、かつインデックスに残ったままになる。

ちなみに、ドキュメント には

If the --keep-index option is used, all changes already added to the index are left intact.

とある。

なお、git version 2.1.3(On ubuntu) と git version 1.9.4.msysgit.1 で試して同じ挙動だった。以下はgit version 2.1.3のログ。

[harupong]

$ git --version
git version 2.1.3
$ git stash list
$ vi README.md
$ git add README.md
$ git status
On branch markdown
Your branch is up-to-date with 'origin/markdown'.
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

        modified:   README.md

$ git diff --staged
diff --git a/README.md b/README.md
index cd87828..f8f9682 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-README
+# README

 ## レビューするファイル

⬆️ Stash is empty. I editted one file and added that to index.

$ git stash save --keep-index
Saved working directory and index state WIP on markdown: 3f347db Apply upstream changes to markdown files
HEAD is now at 3f347db Apply upstream changes to markdown files

⬆️ Then I stashed the change using --keep-index option.

$ git stash list
stash@{0}: WIP on markdown: 3f347db Apply upstream changes to markdown files
$ git stash show stash@{0}
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
$ git stash show -p stash@{0}
diff --git a/README.md b/README.md
index cd87828..f8f9682 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-README
+# README

 ## レビューするファイル

⬆️ One stash is created, with the changes I staged earlier.

$ git status
On branch markdown
Your branch is up-to-date with 'origin/markdown'.
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

        modified:   README.md

$ git diff --staged
diff --git a/README.md b/README.md
index cd87828..f8f9682 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-README
+# README

 ## レビューするファイル

⬆️ index is unchanged, which is the expected behavior of --keep-index option.