[PATCH v2 1/1] commit: display advice hints when commit fails

["Heba Waly via GitGitGadget" <gitgitgadget@gmail.com>]

From: Heba Waly <heba.waly@gmail.com>

Display hints to the user when trying to commit without staging the
modified files first (when advice.statusHints is set to true). Change
the output of the unsuccessful commit from e.g:

  # [...]
  # Changes not staged for commit:
  #   modified:   builtin/commit.c
  #
  # no changes added to commit

to:

  # [...]
  # Changes not staged for commit:
  #   (use "git add <file>..." to update what will be committed)
  #   (use "git checkout -- <file>..." to discard changes in working directory)
  #
  #   modified:   /builtin/commit.c
  #
  # no changes added to commit (use "git add" and/or "git commit -a")

In ea9882bfc4 (commit: disable status hints when writing to
COMMIT_EDITMSG, 2013-09-12) the intent was to disable status hints when
writing to COMMIT_EDITMSG, but in fact the implementation disabled
status messages in more locations, e.g in case the commit wasn't
successful, status hints will still be disabled and no hints will be
displayed to the user although advice.statusHints is set to true.

Signed-off-by: Heba Waly <heba.waly@gmail.com>
---
 builtin/commit.c                          | 18 ++++++++++++------
 t/t7500-commit-template-squash-signoff.sh |  9 +++++++++
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/builtin/commit.c b/builtin/commit.c
index e48c1fd90a..868c0d7819 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -811,12 +811,6 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	old_display_comment_prefix = s->display_comment_prefix;
 	s->display_comment_prefix = 1;
 
-	/*
-	 * Most hints are counter-productive when the commit has
-	 * already started.
-	 */
-	s->hints = 0;
-
 	if (clean_message_contents)
 		strbuf_stripspace(&sb, 0);
 
@@ -837,6 +831,12 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		int saved_color_setting;
 		struct ident_split ci, ai;
 
+		/*
+		 * Most hints are counter-productive when displayed in
+		 * the commit message editor.
+		 */
+		s->hints = 0;
+
 		if (whence != FROM_COMMIT) {
 			if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS &&
 				!merge_contains_scissors)
@@ -912,6 +912,12 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		saved_color_setting = s->use_color;
 		s->use_color = 0;
 		committable = run_status(s->fp, index_file, prefix, 1, s);
+		if(!committable)
+			/*
+			 Status is to be printed to stdout, so hints will be useful to the
+			 user. Reset s->hints to what the user configured
+			 */
+			s->hints = advice_status_hints;
 		s->use_color = saved_color_setting;
 		string_list_clear(&s->change, 1);
 	} else {
diff --git a/t/t7500-commit-template-squash-signoff.sh b/t/t7500-commit-template-squash-signoff.sh
index 46a5cd4b73..a8179e4074 100755
--- a/t/t7500-commit-template-squash-signoff.sh
+++ b/t/t7500-commit-template-squash-signoff.sh
@@ -382,4 +382,13 @@ test_expect_success 'check commit with unstaged rename and copy' '
 	)
 '
 
+test_expect_success 'commit without staging files fails and displays hints' '
+	echo "initial" >>file &&
+	git add file &&
+	git commit -m initial &&
+	echo "changes" >>file &&
+	test_must_fail git commit -m update >actual &&
+	test_i18ngrep "no changes added to commit (use \"git add\" and/or \"git commit -a\")" actual
+'
+
 test_done
-- 
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