diff mbox series

[v2,2/5] commit-graph: verify swapped zero/non-zero generation cases

Message ID 9b9483893c072961c5871bd0bae17a7098d73c06.1691773533.git.me@ttaylorr.com (mailing list archive)
State Superseded
Commit f164de873ae8e8257efd476b510a171a320865b8
Headers show
Series commit-graph: fsck zero/non-zero generation number fixes | expand

Commit Message

Taylor Blau Aug. 11, 2023, 5:05 p.m. UTC 
From: Jeff King <peff@peff.net>

In verify_one_commit_graph(), we have code that complains when a commit
is found with a generation number of zero, and then later with a
non-zero number. It works like this:

  1. When we see an entry with generation zero, we set the
     generation_zero flag to GENERATION_ZERO_EXISTS.

  2. When we later see an entry with a non-zero generation, we complain
     if the flag is GENERATION_ZERO_EXISTS.

There's a matching GENERATION_NUMBER_EXISTS value, which in theory would
be used to find the case that we see the entries in the opposite order:

  1. When we see an entry with a non-zero generation, we set the
     generation_zero flag to GENERATION_NUMBER_EXISTS.

  2. When we later see an entry with a zero generation, we complain if
     the flag is GENERATION_NUMBER_EXISTS.

But that doesn't work; step 2 is implemented, but there is no step 1. We
never use NUMBER_EXISTS at all, and Coverity rightly complains that step
2 is dead code.

We can fix that by implementing that step 1.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 commit-graph.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/commit-graph.c b/commit-graph.c
index c68f5c6b3a..acca753ce8 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -2686,9 +2686,12 @@  static int verify_one_commit_graph(struct repository *r,
 				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));
+		} 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 (generation_zero == GENERATION_ZERO_EXISTS)
 			continue;