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list-objects: handle NULL function pointers

If a caller to traverse_commit_list() specifies the options for the
--objects flag but does not specify a show_object function pointer, the
result is a segfault. This is currently visible by running 'git bundle
create --objects HEAD'.

We could fix this problem by supplying a no-op callback in
builtin/bundle.c, but that only solves the problem for one builtin,
leaving this segfault open for other callers.

Replace all callers of the show_commit and show_object function pointers
in list-objects.c to call helper functions show_commit() and
show_object() which check that the given context has non-NULL functions
before passing the necessary data. One extra benefit is that it reduces
duplication due to passing ctx->show_data to every caller.

Test that this segfault no longer occurs for 'git bundle'.

Co-authored-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pull/1230/head
Ævar Arnfjörð Bjarmason 5 months ago committed by Junio C Hamano
parent
commit
4f33a6345f
  1. 2
      bundle.c
  2. 27
      list-objects.c
  3. 12
      t/t6020-bundle-misc.sh

2
bundle.c

@ -544,6 +544,8 @@ int create_bundle(struct repository *r, const char *path,
die("revision walk setup failed");
bpi.fd = bundle_fd;
bpi.pending = &revs_copy.pending;
revs.blob_objects = revs.tree_objects = 0;
traverse_commit_list(&revs, write_bundle_prerequisites, NULL, &bpi);
object_array_remove_duplicates(&revs_copy.pending);

27
list-objects.c

@ -21,6 +21,23 @@ struct traversal_context {
struct filter *filter;
};
static void show_commit(struct traversal_context *ctx,
struct commit *commit)
{
if (!ctx->show_commit)
return;
ctx->show_commit(commit, ctx->show_data);
}
static void show_object(struct traversal_context *ctx,
struct object *object,
const char *name)
{
if (!ctx->show_object)
return;
ctx->show_object(object, name, ctx->show_data);
}
static void process_blob(struct traversal_context *ctx,
struct blob *blob,
struct strbuf *path,
@ -60,7 +77,7 @@ static void process_blob(struct traversal_context *ctx,
if (r & LOFR_MARK_SEEN)
obj->flags |= SEEN;
if (r & LOFR_DO_SHOW)
ctx->show_object(obj, path->buf, ctx->show_data);
show_object(ctx, obj, path->buf);
strbuf_setlen(path, pathlen);
}
@ -194,7 +211,7 @@ static void process_tree(struct traversal_context *ctx,
if (r & LOFR_MARK_SEEN)
obj->flags |= SEEN;
if (r & LOFR_DO_SHOW)
ctx->show_object(obj, base->buf, ctx->show_data);
show_object(ctx, obj, base->buf);
if (base->len)
strbuf_addch(base, '/');
@ -210,7 +227,7 @@ static void process_tree(struct traversal_context *ctx,
if (r & LOFR_MARK_SEEN)
obj->flags |= SEEN;
if (r & LOFR_DO_SHOW)
ctx->show_object(obj, base->buf, ctx->show_data);
show_object(ctx, obj, base->buf);
strbuf_setlen(base, baselen);
free_tree_buffer(tree);
@ -228,7 +245,7 @@ static void process_tag(struct traversal_context *ctx,
if (r & LOFR_MARK_SEEN)
tag->object.flags |= SEEN;
if (r & LOFR_DO_SHOW)
ctx->show_object(&tag->object, name, ctx->show_data);
show_object(ctx, &tag->object, name);
}
static void mark_edge_parents_uninteresting(struct commit *commit,
@ -402,7 +419,7 @@ static void do_traverse(struct traversal_context *ctx)
if (r & LOFR_MARK_SEEN)
commit->object.flags |= SEEN;
if (r & LOFR_DO_SHOW)
ctx->show_commit(commit, ctx->show_data);
show_commit(ctx, commit);
if (ctx->revs->tree_blobs_in_commit_order)
/*

12
t/t6020-bundle-misc.sh

@ -475,4 +475,16 @@ test_expect_success 'clone from bundle' '
test_cmp expect actual
'
test_expect_success 'unfiltered bundle with --objects' '
git bundle create all-objects.bdl \
--all --objects &&
git bundle create all.bdl \
--all &&
# Compare the headers of these files.
sed -n -e "/^$/q" -e "p" all.bdl >expect &&
sed -n -e "/^$/q" -e "p" all-objects.bdl >actual &&
test_cmp expect actual
'
test_done

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