[PATCH v4 1/1] commit-reach: properly peel tags and clear flags
From: Derrick Stolee <dstolee@microsoft.com>
The can_all_from_reach_with_flag() algorithm was refactored in 4fbcca4e "commit-reach: make can_all_from_reach... linear" but incorrectly assumed that all objects provided were commits. During a fetch negotiation, ok_to_give_up() in upload-pack.c may provide unpeeled tags to the 'from' array. The current code creates a segfault.
Add a direct call to can_all_from_reach_with_flag() in 'test-tool reach' and add a test in t6600-test-reach.sh that demonstrates this segfault.
Correct the issue by peeling tags when investigating the initial list of objects in the 'from' array.
The can_all_from_reach_with_flag() method uses 'assign_flag' as a value we can use to mark objects temporarily during our commit walk. The intent is that these flags are removed from all objects before returning. However, this is not the case.
The 'from' array could also contain objects that are not commits, and we mark those objects with 'assign_flag'. Add a loop to the 'cleanup' section that removes these markers.
Also, we forgot to free() the memory for 'list', so add that to the 'cleanup' section. Also, use a cleaner mechanism for clearing those flags.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
commit-reach.c | 44 +++++++++++++++++++++++++++++++++----------
t/helper/test-reach.c | 22 +++++++++++++++++-----
t/t6600-test-reach.sh | 30 +++++++++++++++++++++++++++--
3 files changed, 79 insertions(+), 17 deletions(-)
Show changes to 3 files +79 −17
commit-reach.c, t/helper/test-reach.c, t/t6600-test-reach.sh
diff --git a/commit-reach.c b/commit-reach.c
index 86715c103c..db84f85986 100644
--- a/commit-reach.c
+++ b/commit-reach.c
@@ -544,20 +544,42 @@ int can_all_from_reach_with_flag(struct object_array *from,
{
struct commit **list = NULL;
int i;
+ int nr_commits;
int result = 1;
ALLOC_ARRAY(list, from->nr);
+ nr_commits = 0;
for (i = 0; i < from->nr; i++) {
- list[i] = (struct commit *)from->objects[i].item;
+ struct object *from_one = from->objects[i].item;
- if (parse_commit(list[i]) ||
- list[i]->generation < min_generation)
- return 0;
+ if (!from_one || from_one->flags & assign_flag)
+ continue;
+
+ from_one = deref_tag(the_repository, from_one,
+ "a from object", 0);
+ if (!from_one || from_one->type != OBJ_COMMIT) {
+ /* no way to tell if this is reachable by
+ * looking at the ancestry chain alone, so
+ * leave a note to ourselves not to worry about
+ * this object anymore.
+ */
+ from->objects[i].item->flags |= assign_flag;
+ continue;
+ }
+
+ list[nr_commits] = (struct commit *)from_one;
+ if (parse_commit(list[nr_commits]) ||
+ list[nr_commits]->generation < min_generation) {
+ result = 0;
+ goto cleanup;
+ }
+
+ nr_commits++;
}
- QSORT(list, from->nr, compare_commits_by_gen);
+ QSORT(list, nr_commits, compare_commits_by_gen);
- for (i = 0; i < from->nr; i++) {
+ for (i = 0; i < nr_commits; i++) {
/* DFS from list[i] */
struct commit_list *stack = NULL;
@@ -600,10 +622,12 @@ int can_all_from_reach_with_flag(struct object_array *from,
}
cleanup:
- for (i = 0; i < from->nr; i++) {
- clear_commit_marks(list[i], RESULT);
- clear_commit_marks(list[i], assign_flag);
- }
+ clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
+ free(list);
+
+ for (i = 0; i < from->nr; i++)
+ from->objects[i].item->flags &= ~assign_flag;
+
return result;
}
diff --git a/t/helper/test-reach.c b/t/helper/test-reach.c
index eb21103998..08d2ea68e8 100644
--- a/t/helper/test-reach.c
+++ b/t/helper/test-reach.c
@@ -31,6 +31,7 @@ int cmd__reach(int ac, const char **av)
struct object_id oid_A, oid_B;
struct commit *A, *B;
struct commit_list *X, *Y;
+ struct object_array X_obj = OBJECT_ARRAY_INIT;
struct commit **X_array;
int X_nr, X_alloc;
struct strbuf buf = STRBUF_INIT;
@@ -49,7 +50,8 @@ int cmd__reach(int ac, const char **av)
while (strbuf_getline(&buf, stdin) != EOF) {
struct object_id oid;
- struct object *o;
+ struct object *orig;
+ struct object *peeled;
struct commit *c;
if (buf.len < 3)
continue;
@@ -57,14 +59,14 @@ int cmd__reach(int ac, const char **av)
if (get_oid_committish(buf.buf + 2, &oid))
die("failed to resolve %s", buf.buf + 2);
- o = parse_object(r, &oid);
- o = deref_tag_noverify(o);
+ orig = parse_object(r, &oid);
+ peeled = deref_tag_noverify(orig);
- if (!o)
+ if (!peeled)
die("failed to load commit for input %s resulting in oid %s\n",
buf.buf, oid_to_hex(&oid));
- c = object_as_type(r, o, OBJ_COMMIT, 0);
+ c = object_as_type(r, peeled, OBJ_COMMIT, 0);
if (!c)
die("failed to load commit for input %s resulting in oid %s\n",
@@ -85,6 +87,7 @@ int cmd__reach(int ac, const char **av)
commit_list_insert(c, &X);
ALLOC_GROW(X_array, X_nr + 1, X_alloc);
X_array[X_nr++] = c;
+ add_object_array(orig, NULL, &X_obj);
break;
case 'Y':
@@ -113,6 +116,15 @@ int cmd__reach(int ac, const char **av)
print_sorted_commit_ids(list);
} else if (!strcmp(av[1], "can_all_from_reach")) {
printf("%s(X,Y):%d\n", av[1], can_all_from_reach(X, Y, 1));
+ } else if (!strcmp(av[1], "can_all_from_reach_with_flag")) {
+ struct commit_list *iter = Y;
+
+ while (iter) {
+ iter->item->object.flags |= 2;
+ iter = iter->next;
+ }
+
+ printf("%s(X,_,_,0,0):%d\n", av[1], can_all_from_reach_with_flag(&X_obj, 2, 4, 0, 0));
} else if (!strcmp(av[1], "commit_contains")) {
struct ref_filter filter;
struct contains_cache cache;
diff --git a/t/t6600-test-reach.sh b/t/t6600-test-reach.sh
index d139a00d1d..ae94b27f70 100755
--- a/t/t6600-test-reach.sh
+++ b/t/t6600-test-reach.sh
@@ -31,7 +31,8 @@ test_expect_success 'setup' '
for i in $(test_seq 1 10)
do
test_commit "1-$i" &&
- git branch -f commit-1-$i
+ git branch -f commit-1-$i &&
+ git tag -a -m "1-$i" tag-1-$i commit-1-$i
done &&
for j in $(test_seq 1 9)
do
@@ -39,11 +40,13 @@ test_expect_success 'setup' '
x=$(($j + 1)) &&
test_commit "$x-1" &&
git branch -f commit-$x-1 &&
+ git tag -a -m "$x-1" tag-$x-1 commit-$x-1 &&
for i in $(test_seq 2 10)
do
git merge commit-$j-$i -m "$x-$i" &&
- git branch -f commit-$x-$i
+ git branch -f commit-$x-$i &&
+ git tag -a -m "$x-$i" tag-$x-$i commit-$x-$i
done
done &&
git commit-graph write --reachable &&
@@ -205,6 +208,29 @@ test_expect_success 'can_all_from_reach:miss' '
test_three_modes can_all_from_reach
'
+test_expect_success 'can_all_from_reach_with_flag: tags case' '
+ cat >input <<-\EOF &&
+ X:tag-2-10
+ X:tag-3-9
+ X:tag-4-8
+ X:commit-5-7
+ X:commit-6-6
+ X:commit-7-5
+ X:commit-8-4
+ X:commit-9-3
+ Y:tag-1-9
+ Y:tag-2-8
+ Y:tag-3-7
+ Y:commit-4-6
+ Y:commit-5-5
+ Y:commit-6-4
+ Y:commit-7-3
+ Y:commit-8-1
+ EOF
+ echo "can_all_from_reach_with_flag(X,_,_,0,0):1" >expect &&
+ test_three_modes can_all_from_reach_with_flag
+'
+
test_expect_success 'commit_contains:hit' '
cat >input <<-\EOF &&
A:commit-7-7
--
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