Merge branch 'ds/commit-graph-merging-fix'

When "git commit-graph" detects the same commit recorded more than
once while it is merging the layers, it used to die.  The code now
ignores all but one of them and continues.

* ds/commit-graph-merging-fix:
  commit-graph: don't write commit-graph when disabled
  commit-graph: ignore duplicates when merging layers
Junio C Hamano 2 years ago
commit 307a53dd99
  1. 4
  2. 21
  3. 13

@ -39,7 +39,9 @@ COMMANDS
Write a commit-graph file based on the commits found in packfiles.
Write a commit-graph file based on the commits found in packfiles. If
the config option `core.commitGraph` is disabled, then this command will
output a warning, then return success without writing a commit-graph file.
With the `--stdin-packs` option, generate the new commit graph by
walking objects only in the specified pack-indexes. (Cannot be combined

@ -2008,7 +2008,7 @@ static int commit_compare(const void *_a, const void *_b)
static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
uint32_t i;
uint32_t i, dedup_i = 0;
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
@ -2023,17 +2023,27 @@ static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
&ctx->commits.list[i]->object.oid)) {
die(_("unexpected duplicate commit id %s"),
* Silently ignore duplicates. These were likely
* created due to a commit appearing in multiple
* layers of the chain, which is unexpected but
* not invalid. We should make sure there is a
* unique copy in the new layer.
} else {
unsigned int num_parents;
ctx->commits.list[dedup_i] = ctx->commits.list[i];
num_parents = commit_list_count(ctx->commits.list[i]->parents);
if (num_parents > 2)
ctx->num_extra_edges += num_parents - 1;
ctx-> = dedup_i;
@ -2150,6 +2160,11 @@ int write_commit_graph(struct object_directory *odb,
int replace = 0;
struct bloom_filter_settings bloom_settings = DEFAULT_BLOOM_FILTER_SETTINGS;
if (!the_repository->settings.core_commit_graph) {
warning(_("attempting to write a commit-graph, but 'core.commitGraph' is disabled"));
return 0;
if (!commit_graph_compatible(the_repository))
return 0;

@ -440,4 +440,17 @@ test_expect_success '--split=replace with partial Bloom data' '
verify_chain_files_exist $graphdir
test_expect_success 'prevent regression for duplicate commits across layers' '
git init dup &&
git -C dup commit --allow-empty -m one &&
git -C dup -c core.commitGraph=false commit-graph write --split=no-merge --reachable 2>err &&
test_i18ngrep "attempting to write a commit-graph" err &&
git -C dup commit-graph write --split=no-merge --reachable &&
git -C dup commit --allow-empty -m two &&
git -C dup commit-graph write --split=no-merge --reachable &&
git -C dup commit --allow-empty -m three &&
git -C dup commit-graph write --split --reachable &&
git -C dup commit-graph verify