Subject: [PATCH] [GSOC] cat-file: fix --batch report changed-type bug

From: "ZheNing Hu via GitGitGadget" <[email-masked]>
Date: Sun, 30 May 2021 08:29:26 +0000

From: ZheNing Hu <[email-masked]>

When we use `--batch` with no atoms formatting and use
`--batch-all-objects` at the same time (e.g.
`git cat-file --batch="batman" --batch-all-objects`),
Git will exit and report "object xxx changed type!?".

This is because we have a format string which does not
contain any atoms, so skip_object_info option will be
set if we also use --batch-all-objects, and then
`oid_object_info_extended()` will be skipped in
`batch_object_write()`, it cause object type to not be
collected. Therefore, it reported object type has changed.

So avoid checking changes in type and size when all_objects
and skip_object_info options are set at the same time.

Signed-off-by: ZheNing Hu <[email-masked]>
---
    [GSOC] cat-file: fix --batch report changed-type bug
    
    "git cat-file --batch-all-objects --batch=batman" will trigger a bug:
    "fatal: object xxx changed type!?"
    
    Although we will replace the logic here in the future, this patch can
    help the old git maintain its functionality.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-965%2Fadlternative%2Fcat-file-batch-bug-fix-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-965/adlternative/cat-file-batch-bug-fix-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/965

 builtin/cat-file.c  | 11 ++++++-----
 t/t1006-cat-file.sh |  6 ++++++
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 5ebf13359e83..5f9578f9b86b 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -345,11 +345,12 @@ static void print_object_or_die(struct batch_options *opt, struct expand_data *d
 		contents = read_object_file(oid, &type, &size);
 		if (!contents)
 			die("object %s disappeared", oid_to_hex(oid));
-		if (type != data->type)
-			die("object %s changed type!?", oid_to_hex(oid));
-		if (data->info.sizep && size != data->size)
-			die("object %s changed size!?", oid_to_hex(oid));
-
+		if (!(opt->all_objects && data->skip_object_info)) {
+			if (type != data->type)
+				die("object %s changed type!?", oid_to_hex(oid));
+			if (data->info.sizep && size != data->size)
+				die("object %s changed size!?", oid_to_hex(oid));
+		}
 		batch_write(opt, contents, size);
 		free(contents);
 	}
diff --git a/t/t1006-cat-file.sh b/t/t1006-cat-file.sh
index 5d2dc99b74ad..9b0f1ae5ef8b 100755
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@ -586,4 +586,10 @@ test_expect_success 'cat-file --unordered works' '
 	test_cmp expect actual
 '
 
+test_expect_success 'cat-file --batch="batman" with --batch-all-objects will work' '
+	git -C all-two cat-file --batch-all-objects --batch="%(objectname)" | wc -l >expect &&
+	git -C all-two cat-file --batch-all-objects --batch="batman" | wc -l >actual &&
+	test_cmp expect actual
+'
+
 test_done

base-commit: 5d5b1473453400224ebb126bf3947e0a3276bdf5
-- 
gitgitgadget