[GSoC PATCH v2 3/4] repack-promisor: preserve content of promisor files after repack

From

LorenzoPegorari <lorenzo.pegorari2002@gmail.com>

Date

Mar 22, 2026, 19:18 UTC

Message-ID

<3dab969a3942532f49f6f9cdcddb5fb2be11e232.1774205661.git.lorenzo.pegorari2002@gmail.com>

In-Reply-To

<cover.1774205661.git.lorenzo.pegorari2002@gmail.com>

Also, update the documentation accordingly.

Signed-off-by: LorenzoPegorari <lorenzo.pegorari2002@gmail.com>
---
 Documentation/git-repack.adoc |  4 ++--
 repack-promisor.c             | 23 +++++++++++++++--------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/Documentation/git-repack.adoc b/Documentation/git-repack.adoc
index 673ce91083..33d3c8afbd 100644
--- a/Documentation/git-repack.adoc
+++ b/Documentation/git-repack.adoc
@@ -45,8 +45,8 @@ other objects in that pack they already have locally.
 +
 Promisor packfiles are repacked separately: if there are packfiles that
 have an associated ".promisor" file, these packfiles will be repacked
-into another separate pack, and an empty ".promisor" file corresponding
-to the new separate pack will be written.
+into another separate pack, and a ".promisor" file corresponding to the
+new separate pack will be written (with arbitrary contents).
 
 -A::
 	Same as `-a`, unless `-d` is used.  Then any unreachable
diff --git a/repack-promisor.c b/repack-promisor.c
index 90318ce150..6670728669 100644
--- a/repack-promisor.c
+++ b/repack-promisor.c
@@ -40,6 +40,7 @@ static void finish_repacking_promisor_objects(struct repository *repo,
 					      const char *packtmp)
 {
 	struct strbuf line = STRBUF_INIT;
+	int is_first_promisor = 1;
 	FILE *out;
 
 	close(cmd->in);
@@ -55,19 +56,25 @@ static void finish_repacking_promisor_objects(struct repository *repo,
 
 		/*
 		 * pack-objects creates the .pack and .idx files, but not the
-		 * .promisor file. Create the .promisor file, which is empty.
-		 *
-		 * NEEDSWORK: fetch-pack sometimes generates non-empty
-		 * .promisor files containing the ref names and associated
-		 * hashes at the point of generation of the corresponding
-		 * packfile, but this would not preserve their contents. Maybe
-		 * concatenate the contents of all .promisor files instead of
-		 * just creating a new empty file.
+		 * .promisor file. Create the .promisor file.
 		 */
 		promisor_name = mkpathdup("%s-%s.promisor", packtmp,
 					  line.buf);
 		write_promisor_file(promisor_name, NULL, 0);
 
+		/*
+		 * Fetch-pack sometimes generates non-empty .promisor files
+		 * containing the ref names and associated hashes at the point of
+		 * generation of the corresponding packfile. These pieces of info
+		 * are only used for debugging reasons. In order to preserve
+		 * these, let's copy the contents of all .promisor files in the
+		 * first promisor file created.
+		 */
+		if (is_first_promisor) {
+			copy_all_promisor_files(repo, promisor_name);
+			is_first_promisor = 0;
+		}
+
 		item->util = generated_pack_populate(item->string, packtmp);
 
 		free(promisor_name);

-- 
2.43.0