[PATCH v2] revision: allow missing promisor objects on CLI

From

JTJonathan Tan <jonathantanmy@google.com>

Date

Dec 30, 2019, 23:44 UTC

Message-ID

<20191230234453.255082-1-jonathantanmy@google.com>

In-Reply-To

<20191228003430.241283-1-jonathantanmy@google.com>

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
Changes from v1: Improved code comments and commit message

> This is the case where oid must be COMMIT from oid_object_info()'s
> point of view, but repo_parse_commit() finds it as a non-commit, and
> object becomes NULL.  This is quite different from the normal lazy
> clone case where exclude-promisor-objects etc. wants to cover, that
> the object whose name is oid is truly missing because it can be
> fetched later from elsewhere.  Instead, we have found that there is
> an inconsistency in the data we have about the object, iow, a
> possible corruption.

If there is corruption in the form of hash mismatch, parse_object() will
print a message and then return NULL, leaving get_reference() to handle
it - and treat it as missing in this case. It seems reasonable to me to
handle the repo_parse_commit() failure in a similar way. I've added
comments to clarify that error messages are being printed.
---
 revision.c               | 23 ++++++++++++++++++++++-
 t/t0410-partial-clone.sh | 10 ++--------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/revision.c b/revision.c
index 8136929e23..af1e31b4fc 100644
--- a/revision.c
+++ b/revision.c
@@ -370,8 +370,18 @@ static struct object *get_reference(struct rev_info *revs, const char *name,
 		if (!repo_parse_commit(revs->repo, c))
 			object = (struct object *) c;
 		else
+			/*
+			 * There is something wrong with the commit.
+			 * repo_parse_commit() will have already printed an
+			 * error message. For our purposes, treat as missing.
+			 */
 			object = NULL;
 	} else {
+		/*
+		 * There is something wrong with the object. parse_object()
+		 * will have already printed an error message. For our
+		 * purposes, treat as missing.
+		 */
 		object = parse_object(revs->repo, oid);
 	}
 
@@ -1907,7 +1917,18 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
 		verify_non_filename(revs->prefix, arg);
 	object = get_reference(revs, arg, &oid, flags ^ local_flags);
 	if (!object)
-		return revs->ignore_missing ? 0 : -1;
+		/*
+		 * If this object is corrupt, get_reference() prints an error
+		 * message and treats it as missing.
+		 *
+		 * get_reference() returns NULL only if this object is missing
+		 * and ignore_missing is true, or this object is a (missing)
+		 * promisor object and exclude_promisor_objects is true. In
+		 * both these cases, we can safely ignore this object because
+		 * this object will not appear in output and cannot be used as
+		 * a source of UNINTERESTING ancestors (since it is missing).
+		 */
+		return 0;
 	add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
 	add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
 	free(oc.path);
diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
index a3988bd4b8..fd28f5402a 100755
--- a/t/t0410-partial-clone.sh
+++ b/t/t0410-partial-clone.sh
@@ -416,15 +416,9 @@ test_expect_success 'rev-list dies for missing objects on cmd line' '
 	git -C repo config extensions.partialclone "arbitrary string" &&
 
 	for OBJ in "$COMMIT" "$TREE" "$BLOB"; do
-		test_must_fail git -C repo rev-list --objects \
+		git -C repo rev-list --objects \
 			--exclude-promisor-objects "$OBJ" &&
-		test_must_fail git -C repo rev-list --objects-edge-aggressive \
-			--exclude-promisor-objects "$OBJ" &&
-
-		# Do not die or crash when --ignore-missing is passed.
-		git -C repo rev-list --ignore-missing --objects \
-			--exclude-promisor-objects "$OBJ" &&
-		git -C repo rev-list --ignore-missing --objects-edge-aggressive \
+		git -C repo rev-list --objects-edge-aggressive \
 			--exclude-promisor-objects "$OBJ"
 	done
 '

-- 
2.24.1.735.g03f4e72817-goog