Re: How to prevent empty git commit --amend

Junio C Hamano [off-list ref] writes:

Matthieu Moy [off-list ref] writes:

quoted

Ivo Anjo [off-list ref] writes:

quoted

Is there a way to prevent a *git commit --amend** with nothing to
commit from working?
If not, I would like to suggest that this feature would be very helpful :)

I don't know any way to let Git do the check for you, but 

git diff --staged --quiet || git commit --amend

should do it. You can alias it like

[alias]
	amend = !git diff --staged --quiet || git commit --amend

and then use "git amend".

That would not let you say "git amend Makefile", no?

	!sh -c 'git diff --cached --quiet "$@" || git commit --amend "$@"' -

or something, perhaps?

Heh, not that but something like that ;-).

 * If we have pathspec, we would want to see if the HEAD and the
   working tree differ at the given paths;

 * Otherwise we would want to see if the HEAD and the index differ.

So it would be more like this, I guess.

	case "$#" in
        0)	git diff --quiet --cached ;;
        *)	git diff --quiet HEAD -- "$@" ;;
	esac || git commit --amend ${1+--} "$@"

git commit and git status in long format show the diff between HEAD
and the index when given -v. This allows previewing a commit to be made.

They also list tracked files with unstaged changes, but without a diff.

Introduce '-v -v' which shows the diff between the index and the
worktree in addition to HEAD index diff. This allows to review unstaged
changes which might be missing from the commit.

Signed-off-by: Michael J Gruber <redacted>
---
Also, the git status man page does not mention -v at all, and the doc
for git status (long format) and the status parts of the git commit
man page should really be the same.

In any case, this may have helped the OP with his amend oversight.

 Documentation/git-commit.txt | 4 ++++
 wt-status.c                  | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index 1e74b75..f14d2ec 100644
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt

@@ -284,6 +284,10 @@ configuration variable documented in linkgit:git-config[1].
 	would be committed at the bottom of the commit message
 	template.  Note that this diff output doesn't have its
 	lines prefixed with '#'.
++
+If specified twice, show in addition the unified diff between
+what would be committed and the worktree files, i.e. the unstaged
+changes to tracked files.
 
 -q::
 --quiet::

diff --git a/wt-status.c b/wt-status.c
index b54eac5..75674c2 100644
--- a/wt-status.c
+++ b/wt-status.c

@@ -874,6 +874,14 @@ static void wt_status_print_verbose(struct wt_status *s)
 		wt_status_add_cut_line(s->fp);
 	}
 	run_diff_index(&rev, 1);
+	if (s->verbose > 1) {
+		setup_work_tree();
+		if (read_cache_preload(&rev.diffopt.pathspec) < 0)
+			perror("read_cache_preload");
+		rev.diffopt.a_prefix = 0; /* allow run_diff_files */
+		rev.diffopt.b_prefix = 0; /* to reset the prefixes */
+		run_diff_files(&rev, 0);
+	}
 }
 
 static void wt_status_print_tracking(struct wt_status *s)

-- 
2.3.0.rc0.202.g6f441c7