Re: [BUG] git stash refuses to save after "add -N"

[Jeff King <peff@peff.net>]

On Sun, Aug 30, 2009 at 01:01:11PM -0700, Junio C Hamano wrote:

> > And all of this while they are trying to quickly switch contexts to
> > whatever it was that caused them to stash in the first place.
> 
> Ok, then probably the "how about" patch would be a part of the right
> solution.

And then something like this on top (assuming you cut the change to
git-stash.sh from yours).

My concerns are:

  - "-f" is kind of vague. Would people expect it to force aspects of
    the stash? Should it be "--intent-as-empty"?

  - the error message is still a bit muddled, because you get the "not
    yet added" files _first_, then some failure cruft from write-tree,
    and _then_ the trying-to-be-helpful message

I dunno. Honestly I am a bit lukewarm about this whole thing, as it
seems like something that just wouldn't come up that often, and while
the current error message is a bit disorganized, I think a user who has
used "git add -N" can figure out that it is related (the only report we
have is from Yann, who _did_ figure it out, but wanted to know how to
make git handle the situation better).

diff --git a/git-stash.sh b/git-stash.sh
index d61c9d0..963cad0 100755
--- a/git-stash.sh
+++ b/git-stash.sh
@@ -20,6 +20,7 @@ TMP="$GIT_DIR/.git-stash.$$"
 trap 'rm -f "$TMP-*"' 0
 
 ref_stash=refs/stash
+force=
 
 no_changes () {
 	git diff-index --quiet --cached HEAD --ignore-submodules -- &&
@@ -63,7 +64,14 @@ create_stash () {
 	msg=$(printf '%s: %s' "$branch" "$head")
 
 	# state of the index
-	i_tree=$(git write-tree) &&
+	if ! i_tree=$(git write-tree ${force:+--intent-as-empty}); then
+		case "$force" in
+		t) die 'Cannot save the current index state';;
+		*) echo >&2 'fatal: unable to create tree; if some files are marked as'
+		   echo >&2 '"not added yet", you may override with "git stash save -f"'
+		   exit 1
+		esac
+	fi
 	i_commit=$(printf 'index on %s\n' "$msg" |
 		git commit-tree $i_tree -p $b_commit) ||
 		die "Cannot save the current index state"
@@ -104,6 +112,9 @@ save_stash () {
 		-q|--quiet)
 			GIT_QUIET=t
 			;;
+		-f|--force)
+			force=t
+			;;
 		*)
 			break
 			;;
diff --git a/t/t3904-stash-intent.sh b/t/t3904-stash-intent.sh
new file mode 100755
index 0000000..ec7dd12
--- /dev/null
+++ b/t/t3904-stash-intent.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+test_description='stash with intent-to-add index entries'
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	echo content >base &&
+	git add base &&
+	git commit -m base &&
+	echo foo content >foo &&
+	echo bar content >bar &&
+	git add foo &&
+	git add -N bar
+'
+
+test_expect_success 'stash save refuses intent-to-add entry' '
+	test_must_fail git stash save
+'
+
+test_expect_success 'stash save -f allows intent-to-add' '
+	git stash save -f &&
+	git show stash^2:foo >foo.stash &&
+	echo foo content >expect &&
+	test_cmp expect foo.stash &&
+	>expect &&
+	git show stash^2:bar >bar.stash &&
+	test_cmp expect bar.stash
+'
+
+test_done