commit-graph: avoid repeated mixed generation number warnings

When validating that a commit-graph has either all zero, or all non-zero
generation numbers, we emit a warning on both the rising and falling
edge of transitioning between the two.

So if we are unfortunate enough to see a commit-graph which has a
repeating sequence of zero, then non-zero generation numbers, we'll
generate many warnings that contain more or less the same information.

Avoid this by keeping track of a single example for a commit with zero-
and non-zero generation, and emit a single warning at the end of
verification if both are non-NULL.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/commit-graph.c b/commit-graph.c
index acca753ce8b953d400f447ca18e642a5dda3064d..9e6eaa8a46b3663979acc32c5b5a2d402d8771ee 100644 (file)
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -2560,9 +2560,6 @@ static void graph_report(const char *fmt, ...)
        va_end(ap);
 }
 
-#define GENERATION_ZERO_EXISTS 1
-#define GENERATION_NUMBER_EXISTS 2
-
 static int commit_graph_checksum_valid(struct commit_graph *g)
 {
        return hashfile_checksum_valid(g->data, g->data_len);
@@ -2575,7 +2572,8 @@ static int verify_one_commit_graph(struct repository *r,
 {
        uint32_t i, cur_fanout_pos = 0;
        struct object_id prev_oid, cur_oid;
-       int generation_zero = 0;
+       struct commit *seen_gen_zero = NULL;
+       struct commit *seen_gen_non_zero = NULL;
 
        verify_commit_graph_error = verify_commit_graph_lite(g);
        if (verify_commit_graph_error)
@@ -2681,19 +2679,12 @@ static int verify_one_commit_graph(struct repository *r,
                        graph_report(_("commit-graph parent list for commit %s terminates early"),
                                     oid_to_hex(&cur_oid));
 
-               if (!commit_graph_generation_from_graph(graph_commit)) {
-                       if (generation_zero == GENERATION_NUMBER_EXISTS)
-                               graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
-                                            oid_to_hex(&cur_oid));
-                       generation_zero = GENERATION_ZERO_EXISTS;
-               } else {
-                       if (generation_zero == GENERATION_ZERO_EXISTS)
-                               graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
-                                            oid_to_hex(&cur_oid));
-                       generation_zero = GENERATION_NUMBER_EXISTS;
-               }
+               if (commit_graph_generation_from_graph(graph_commit))
+                       seen_gen_non_zero = graph_commit;
+               else
+                       seen_gen_zero = graph_commit;
 
-               if (generation_zero == GENERATION_ZERO_EXISTS)
+               if (seen_gen_zero)
                        continue;
 
                /*
@@ -2719,6 +2710,12 @@ static int verify_one_commit_graph(struct repository *r,
                                     odb_commit->date);
        }
 
+       if (seen_gen_zero && seen_gen_non_zero)
+               graph_report(_("commit-graph has both zero and non-zero "
+                              "generations (e.g., commits '%s' and '%s')"),
+                            oid_to_hex(&seen_gen_zero->object.oid),
+                            oid_to_hex(&seen_gen_non_zero->object.oid));
+
        return verify_commit_graph_error;
 }
 

diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 8e96471b34d960e0becd00cbaab1a0fb98c97edf..ba65f17dd9cc863a9a92ae90393af3ffdd2309de 100755 (executable)
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -620,12 +620,12 @@ test_expect_success 'detect incorrect chunk count' '
 
 test_expect_success 'detect mixed generation numbers (non-zero to zero)' '
        corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_GENERATION_LAST "\0\0\0\0" \
-               "but non-zero elsewhere"
+               "both zero and non-zero generations"
 '
 
 test_expect_success 'detect mixed generation numbers (zero to non-zero)' '
        corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_GENERATION "\0\0\0\0" \
-               "but zero elsewhere"
+               "both zero and non-zero generations"
 '
 
 test_expect_success 'git fsck (checks commit-graph when config set to true)' '