Re: Merge made by recursive?

From: Jeff King <hidden>
Date: 2016-06-15 22:51:19
Subsystem: the rest · Maintainer: Linus Torvalds

Possibly related (same subject, not in this thread)

2016-06-15 · Merge made by recursive? · Shawn Ligocki <hidden>
2016-06-15 · Re: Merge made by recursive? · Ramkumar Ramachandra <hidden>
2016-06-15 · Re: Merge made by recursive? · Jakub Narebski <hidden>
2016-06-15 · Re: Merge made by recursive? · Junio C Hamano <hidden>
2016-06-15 · Re: Merge made by recursive? · Jeff King <hidden>

On Wed, May 25, 2011 at 05:25:10PM -0400, Jeff King wrote:

Though if we are going to change it, I think my preference would
actually be:

  8e46cad HEAD@{0}: reset: moving to HEAD^

which reads better. The "updating HEAD" is just pointless. Of course
we're updating HEAD; we're in the HEAD reflog and we're running reset!

Actually, this gets written also to the branch's reflog, so saying
"updating HEAD" has a little bit of value. Of course, saying "reset" is
even better, since that is the command to update HEAD.

However, if GIT_REFLOG_ACTION is already set (by a script calling us),
then we won't say "reset". So for example, I have entries in my reflog
like:

  944af8c HEAD@{311}: rebase -i (squash): updating HEAD

So maybe it makes sense to leave those ones as-is, and adjust only the
case where GIT_REFLOG_ACTION is unset.

...and for the reason above, it makes sense to leave this as "updating
HEAD" for the per-branch reflog, since whatever the script put into
GIT_REFLOG_ACTION may be more clear with that information.

So here's what I think we should do.

-- >8 --
Subject: [PATCH] reset: give better reflog messages

The reset command creates its reflog entry from argv.
However, it does so after having run parse_options, which
means the only thing left in argv is any non-option
arguments. Thus you would end up with confusing reflog
entries like:

  $ git reset --hard HEAD^
  $ git reset --soft HEAD@{1}
  $ git log -2 -g --oneline
  8e46cad HEAD@{0}: HEAD@{1}: updating HEAD
  1eb9486 HEAD@{1}: HEAD^: updating HEAD

However, we must also consider that some scripts may set
GIT_REFLOG_ACTION before calling reset, and we need to show
their reflog action (with our text appended). For example:

  rebase -i (squash): updating HEAD

On top of that, we also set the ORIG_HEAD reflog action
(even though it doesn't generally exist). In that case, the
reset argument is somewhat meaningless, as it has nothing to
do with what's in ORIG_HEAD.

This patch changes the reset reflog code to show:

  $GIT_REFLOG_ACTION: updating {HEAD,ORIG_HEAD}

as before, but only if GIT_REFLOG_ACTION is set. Otherwise,
show:

   reset: moving to $rev

for HEAD, and:

   reset: updating ORIG_HEAD

for ORIG_HEAD (this is still somewhat superfluous, since we
are in the ORIG_HEAD reflog, obviously, but at least we now
mention which command was used to update it).

While we're at it, we can clean up the code a bit:

  1. Use strbufs to make the message.

  1. Use the "rev" parameter instead of showing all options.
     This makes more sense, since it is the only thing
     impacting the writing of the ref.

Signed-off-by: Jeff King <redacted>
---
 builtin/reset.c        |   49 +++++++++++++++--------------------------------
 t/t1412-reflog-loop.sh |    8 +++---
 2 files changed, 20 insertions(+), 37 deletions(-)

diff --git a/builtin/reset.c b/builtin/reset.c
index 98bca04..27b3426 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c

@@ -33,25 +33,6 @@ static const char *reset_type_names[] = {
 	N_("mixed"), N_("soft"), N_("hard"), N_("merge"), N_("keep"), NULL
 };
 
-static char *args_to_str(const char **argv)
-{
-	char *buf = NULL;
-	unsigned long len, space = 0, nr = 0;
-
-	for (; *argv; argv++) {
-		len = strlen(*argv);
-		ALLOC_GROW(buf, nr + 1 + len, space);
-		if (nr)
-			buf[nr++] = ' ';
-		memcpy(buf + nr, *argv, len);
-		nr += len;
-	}
-	ALLOC_GROW(buf, nr + 1, space);
-	buf[nr] = '\0';
-
-	return buf;
-}
-
 static inline int is_merge(void)
 {
 	return !access(git_path("MERGE_HEAD"), F_OK);

@@ -215,14 +196,18 @@ static int read_from_tree(const char *prefix, const char **argv,
 	return update_index_refresh(index_fd, lock, refresh_flags);
 }
 
-static void prepend_reflog_action(const char *action, char *buf, size_t size)
+static void set_reflog_message(struct strbuf *sb, const char *action,
+			       const char *rev)
 {
-	const char *sep = ": ";
 	const char *rla = getenv("GIT_REFLOG_ACTION");
-	if (!rla)
-		rla = sep = "";
-	if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
-		warning(_("Reflog action message too long: %.*s..."), 50, buf);
+
+	strbuf_reset(sb);
+	if (rla)
+		strbuf_addf(sb, "%s: %s", rla, action);
+	else if (rev)
+		strbuf_addf(sb, "reset: moving to %s", rev);
+	else
+		strbuf_addf(sb, "reset: %s", action);
 }
 
 static void die_if_unmerged_cache(int reset_type)

@@ -241,7 +226,7 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 				*old_orig = NULL, sha1_old_orig[20];
 	struct commit *commit;
-	char *reflog_action, msg[1024];
+	struct strbuf msg = STRBUF_INIT;
 	const struct option options[] = {
 		OPT__QUIET(&quiet, "be quiet, only report errors"),
 		OPT_SET_INT(0, "mixed", &reset_type,

@@ -261,8 +246,6 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 
 	argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 						PARSE_OPT_KEEP_DASHDASH);
-	reflog_action = args_to_str(argv);
-	setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 
 	/*
 	 * Possible arguments are:

@@ -357,13 +340,13 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 		old_orig = sha1_old_orig;
 	if (!get_sha1("HEAD", sha1_orig)) {
 		orig = sha1_orig;
-		prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
-		update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
+		set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
+		update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 	}
 	else if (old_orig)
 		delete_ref("ORIG_HEAD", old_orig, 0);
-	prepend_reflog_action("updating HEAD", msg, sizeof(msg));
-	update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
+	set_reflog_message(&msg, "updating HEAD", rev);
+	update_ref_status = update_ref(msg.buf, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 
 	switch (reset_type) {
 	case HARD:

@@ -380,7 +363,7 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 
 	remove_branch_state();
 
-	free(reflog_action);
+	strbuf_release(&msg);
 
 	return update_ref_status;
 }

diff --git a/t/t1412-reflog-loop.sh b/t/t1412-reflog-loop.sh
index 7f519e5..647d888 100755
--- a/t/t1412-reflog-loop.sh
+++ b/t/t1412-reflog-loop.sh

@@ -21,10 +21,10 @@ test_expect_success 'setup reflog with alternating commits' '
 
 test_expect_success 'reflog shows all entries' '
 	cat >expect <<-\EOF
-		topic@{0} two: updating HEAD
-		topic@{1} one: updating HEAD
-		topic@{2} two: updating HEAD
-		topic@{3} one: updating HEAD
+		topic@{0} reset: moving to two
+		topic@{1} reset: moving to one
+		topic@{2} reset: moving to two
+		topic@{3} reset: moving to one
 		topic@{4} branch: Created from HEAD
 	EOF
 	git log -g --format="%gd %gs" topic >actual &&

-- 
1.7.4.5.34.g0787f

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