Subject: [PATCH v2 2/6] builtin/update-index: end ODB transaction when --verbose is specified

From: Justin Tobler <[email-masked]>
Date: Mon, 15 Sep 2025 15:29:52 -0500

With 23a3a303 (update-index: use the bulk-checkin infrastructure,
2022-04-04), object database transactions were added to
git-update-index(1) to facilitate writing objects in bulk. With
transactions, newly added objects are instead written to a temporary
object directory and migrated to the primary object database upon
transaction commit.

When the --verbose option is specified, each of the following objects is
explicitly flushed via flush_odb_transaction() prior to reporting the
update. Flushing the object database transaction migrates pending
objects to the primary object database without marking the transaction
as complete. This is done so objects are immediately visible to
git-update-index(1) callers using the --verbose option and that rely on
parsing verbose output to know when objects are written.

Due to how git-update-index(1) parses options, each filename argument is
evaluated with only the set of options that precede it. Therefore, it is
possible for an initial set of objects to be written in a transaction
before a --verbose option is encountered.

As soon as the --verbose option is parsed in git-update-index(1), all
subsequent object writes are flushed prior to being reported and thus no
longer benefit from being transactional. Furthermore, the mechanism to
flush a transaction without committing is rather awkward. Drop the call
to flush_odb_transaction() in favor of ending the transaction early when
the --verbose flag is encountered.

Signed-off-by: Justin Tobler <[email-masked]>
---
 builtin/update-index.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/builtin/update-index.c b/builtin/update-index.c
index 2ba2d29c95..d36bc55752 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -70,14 +70,6 @@ static void report(const char *fmt, ...)
 	if (!verbose)
 		return;
 
-	/*
-	 * It is possible, though unlikely, that a caller could use the verbose
-	 * output to synchronize with addition of objects to the object
-	 * database. The current implementation of ODB transactions leaves
-	 * objects invisible while a transaction is active, so flush the
-	 * transaction here before reporting a change made by update-index.
-	 */
-	flush_odb_transaction(the_repository->objects->transaction);
 	va_start(vp, fmt);
 	vprintf(fmt, vp);
 	putchar('\n');
@@ -1150,6 +1142,21 @@ int cmd_update_index(int argc,
 			const char *path = ctx.argv[0];
 			char *p;
 
+			/*
+			 * It is possible, though unlikely, that a caller could
+			 * use the verbose output to synchronize with addition
+			 * of objects to the object database. The current
+			 * implementation of ODB transactions leaves objects
+			 * invisible while a transaction is active, so end the
+			 * transaction here early before processing the next
+			 * update. All further updates are performed outside of
+			 * a transaction.
+			 */
+			if (transaction && verbose) {
+				end_odb_transaction(transaction);
+				transaction = NULL;
+			}
+
 			setup_work_tree();
 			p = prefix_path(prefix, prefix_length, path);
 			update_one(p);
-- 
2.51.0.193.g4975ec3473b