Merge branch 'ps/do-not-trust-commit-graph-blindly-for-existence'

The codepath to traverse the commit-graph learned to notice that a
commit is missing (e.g., corrupt repository lost an object), even
though it knows something about the commit (like its parents) from
what is in commit-graph.

* ps/do-not-trust-commit-graph-blindly-for-existence:
  commit: detect commits that exist in commit-graph but not in the ODB
  commit-graph: introduce envvar to disable commit existence checks

1 files changed, 10 insertions, 0 deletions

diff --git a/Documentation/git.txt b/Documentation/git.txt
index 9aeabde262..2535a30194 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -911,6 +911,16 @@ for full details.
 	should not normally need to set this to `0`, but it may be
 	useful when trying to salvage data from a corrupted repository.
 
+`GIT_COMMIT_GRAPH_PARANOIA`::
+	When loading a commit object from the commit-graph, Git performs an
+	existence check on the object in the object database. This is done to
+	avoid issues with stale commit-graphs that contain references to
+	already-deleted commits, but comes with a performance penalty.
++
+The default is "true", which enables the aforementioned behavior.
+Setting this to "false" disables the existence check. This can lead to
+a performance improvement at the cost of consistency.
+
 `GIT_ALLOW_PROTOCOL`::
 	If set to a colon-separated list of protocols, behave as if
 	`protocol.allow` is set to `never`, and each of the listed