git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH 2/2] refs.c: avoid creating extra unwanted reflog entries

From
Kyle J. McKay <mackyle@gmail.com>
Date
Jan 30, 2021, 10:19 UTC
Message-ID
<1e8c8e3d23d3c2ddf031e3d7719241c@72481c9465c8b2c4aaff8b77ab5e23c>
In-Reply-To
<7c7e8679f2da7e1475606d698b2da8c@72481c9465c8b2c4aaff8b77ab5e23c>

Since commit 523fa69c36744ae6 ("reflog: cleanse messages in the refs.c layer", 2020-07-10, v2.29.0), ref log messages are now being "cleansed" to make sure they do not end up breaking the ref log files. A laudable endeavor.

Unfortunately, that commit had an unintended side effect that causes the `git symbolic-ref <refname1> <refname2>` command to suddenly start adding new entries to the ref log for <refname1> whenever it's run.

These new entries have a completely empty message and do not provide any useful information. In fact, there was no mention that the change to "cleanse" ref log messages was intended to add these new ref log entries at all.

What happened is that when the change to "cleanse" the incoming ref log message was made, the code started inadvertently transforming a NULL ref log message pointer into an empty string "".

This created the observed effect that using the `symbolic-ref` command suddenly started causing ref log entries to be added.

The original code that predated the "cleanse" commit called the `xstrdup_or_null` function to retain the original NULL pointer and avoid introducing unwanted extra ref log entries.

After the "cleanse" commit, ref log messages are now funnelled through a new static function named `normalize_reflog_message`.

Eliminate the unwanted extra blank ref log entries by returning a NULL pointer when NULL is passed into `normalize_reflog_message` rather than returning a pointer to an empty string ("").

To reflect this new behavior, rename the function to `normalize_reflog_message_or_null` in the same spirit as the name of the `xstrdup_or_null` function that was called pre-"cleanse".

Flip the `test_expect_failure` tests to `test_expect_success` as they now pass again.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
---
 refs.c                   | 16 +++++++++-------
 t/t1417-reflog-symref.sh |  6 +++---
 2 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/refs.c b/refs.c
index 03968ad7..790b1ff0 100644
--- a/refs.c
+++ b/refs.c
@@ -835,11 +835,13 @@ static void copy_reflog_msg(struct strbuf *sb, const char *msg)
 	strbuf_rtrim(sb);
 }
 
-static char *normalize_reflog_message(const char *msg)
+static char *normalize_reflog_message_or_null(const char *msg)
 {
 	struct strbuf sb = STRBUF_INIT;
 
-	if (msg && *msg)
+	if (!msg)
+		return NULL;
+	if (*msg)
 		copy_reflog_msg(&sb, msg);
 	return strbuf_detach(&sb, NULL);
 }
@@ -1067,7 +1069,7 @@ struct ref_update *ref_transaction_add_update(
 		oidcpy(&update->new_oid, new_oid);
 	if (flags & REF_HAVE_OLD)
 		oidcpy(&update->old_oid, old_oid);
-	update->msg = normalize_reflog_message(msg);
+	update->msg = normalize_reflog_message_or_null(msg);
 	return update;
 }
 
@@ -1951,7 +1953,7 @@ int refs_create_symref(struct ref_store *refs,
 	char *msg;
 	int retval;
 
-	msg = normalize_reflog_message(logmsg);
+	msg = normalize_reflog_message_or_null(logmsg);
 	retval = refs->be->create_symref(refs, ref_target, refs_heads_master,
 					 msg);
 	free(msg);
@@ -2339,7 +2341,7 @@ int refs_delete_refs(struct ref_store *refs, const char *logmsg,
 	char *msg;
 	int retval;
 
-	msg = normalize_reflog_message(logmsg);
+	msg = normalize_reflog_message_or_null(logmsg);
 	retval = refs->be->delete_refs(refs, msg, refnames, flags);
 	free(msg);
 	return retval;
@@ -2357,7 +2359,7 @@ int refs_rename_ref(struct ref_store *refs, const char *oldref,
 	char *msg;
 	int retval;
 
-	msg = normalize_reflog_message(logmsg);
+	msg = normalize_reflog_message_or_null(logmsg);
 	retval = refs->be->rename_ref(refs, oldref, newref, msg);
 	free(msg);
 	return retval;
@@ -2374,7 +2376,7 @@ int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
 	char *msg;
 	int retval;
 
-	msg = normalize_reflog_message(logmsg);
+	msg = normalize_reflog_message_or_null(logmsg);
 	retval = refs->be->copy_ref(refs, oldref, newref, msg);
 	free(msg);
 	return retval;
diff --git a/t/t1417-reflog-symref.sh b/t/t1417-reflog-symref.sh
index 6149531f..3687b058 100755
--- a/t/t1417-reflog-symref.sh
+++ b/t/t1417-reflog-symref.sh
@@ -53,7 +53,7 @@ test_expect_success setup '
 	test $hcnt -ne $kcnt
 '
 
-test_expect_failure 'HEAD reflog symbolic-ref' '
+test_expect_success 'HEAD reflog symbolic-ref' '
 	hcnt1=$(git reflog show HEAD | wc -l) &&
 	git symbolic-ref HEAD refs/heads/unu &&
 	git symbolic-ref HEAD refs/heads/du &&
@@ -62,7 +62,7 @@ test_expect_failure 'HEAD reflog symbolic-ref' '
 	test $hcnt1 = $hcnt2
 '
 
-test_expect_failure 'refs/heads/KVAR reflog symbolic-ref' '
+test_expect_success 'refs/heads/KVAR reflog symbolic-ref' '
 	kcnt1=$(git reflog show refs/heads/KVAR | wc -l) &&
 	git symbolic-ref refs/heads/KVAR refs/heads/tri &&
 	git symbolic-ref refs/heads/KVAR refs/heads/du &&
@@ -71,7 +71,7 @@ test_expect_failure 'refs/heads/KVAR reflog symbolic-ref' '
 	test $kcnt1 = $kcnt2
 '
 
-test_expect_failure 'double symref reflog symbolic-ref' '
+test_expect_success 'double symref reflog symbolic-ref' '
 	hcnt1=$(git reflog show HEAD | wc -l) &&
 	kcnt1=$(git reflog show refs/heads/KVAR | wc -l) &&
 	git symbolic-ref HEAD refs/heads/KVAR &&
Previous: Kyle J. McKayNext: Kyle J. McKay
Message 2 of 9 in “Eliminate extraneous ref log entries”
  1. 0/2 Eliminate extraneous ref log entriesKyle J. McKay, Jan 30, 2021
  2. 2/2 refs.c: avoid creating extra unwanted reflog entriesKyle J. McKay, Jan 30, 2021
  3. 1/2 t/t1417: test symbolic-ref effects on ref logsKyle J. McKay, Jan 30, 2021
  4. Junio C HamanoJan 30, 2021
  5. Kyle J. McKayJan 30, 2021
  6. Junio C HamanoJan 30, 2021
  7. Han-Wen NienhuysFeb 1, 2021
  8. Kyle J. McKayJan 30, 2021
  9. Junio C HamanoJan 31, 2021

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.