commit-reach(paint_down_to_common): start reporting errors

If a commit cannot be parsed, it is currently ignored when looking for
merge bases. That's undesirable as the operation can pretend success in
a corrupt repository, even though the command should fail with an error
message.

Let's start at the bottom of the stack by teaching the
`paint_down_to_common()` function to return an `int`: if negative, it
indicates fatal error, if 0 success.

This requires a couple of callers to be adjusted accordingly.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/commit-reach.c b/commit-reach.c
index 616738fc4e18c68099a936c9cdeb5a01719e1d50..267fcfc6caffe1e04b36e81740ad5e7801cca03a 100644 (file)
--- a/commit-reach.c
+++ b/commit-reach.c
@@ -49,14 +49,14 @@ static int queue_has_nonstale(struct prio_queue *queue)
 }
 
 /* all input commits in one and twos[] must have been parsed! */
-static struct commit_list *paint_down_to_common(struct repository *r,
-                                               struct commit *one, int n,
-                                               struct commit **twos,
-                                               timestamp_t min_generation,
-                                               int ignore_missing_commits)
+static int paint_down_to_common(struct repository *r,
+                               struct commit *one, int n,
+                               struct commit **twos,
+                               timestamp_t min_generation,
+                               int ignore_missing_commits,
+                               struct commit_list **result)
 {
        struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
-       struct commit_list *result = NULL;
        int i;
        timestamp_t last_gen = GENERATION_NUMBER_INFINITY;
 
@@ -65,8 +65,8 @@ static struct commit_list *paint_down_to_common(struct repository *r,
 
        one->object.flags |= PARENT1;
        if (!n) {
-               commit_list_append(one, &result);
-               return result;
+               commit_list_append(one, result);
+               return 0;
        }
        prio_queue_put(&queue, one);
 
@@ -94,7 +94,7 @@ static struct commit_list *paint_down_to_common(struct repository *r,
                if (flags == (PARENT1 | PARENT2)) {
                        if (!(commit->object.flags & RESULT)) {
                                commit->object.flags |= RESULT;
-                               commit_list_insert_by_date(commit, &result);
+                               commit_list_insert_by_date(commit, result);
                        }
                        /* Mark parents of a found merge stale */
                        flags |= STALE;
@@ -107,7 +107,8 @@ static struct commit_list *paint_down_to_common(struct repository *r,
                                continue;
                        if (repo_parse_commit(r, p)) {
                                clear_prio_queue(&queue);
-                               free_commit_list(result);
+                               free_commit_list(*result);
+                               *result = NULL;
                                /*
                                 * At this stage, we know that the commit is
                                 * missing: `repo_parse_commit()` uses
@@ -115,7 +116,10 @@ static struct commit_list *paint_down_to_common(struct repository *r,
                                 * corrupt commits would already have been
                                 * dispatched with a `die()`.
                                 */
-                               return NULL;
+                               if (ignore_missing_commits)
+                                       return 0;
+                               return error(_("could not parse commit %s"),
+                                            oid_to_hex(&p->object.oid));
                        }
                        p->object.flags |= flags;
                        prio_queue_put(&queue, p);
@@ -123,7 +127,7 @@ static struct commit_list *paint_down_to_common(struct repository *r,
        }
 
        clear_prio_queue(&queue);
-       return result;
+       return 0;
 }
 
 static struct commit_list *merge_bases_many(struct repository *r,
@@ -150,7 +154,10 @@ static struct commit_list *merge_bases_many(struct repository *r,
                        return NULL;
        }
 
-       list = paint_down_to_common(r, one, n, twos, 0, 0);
+       if (paint_down_to_common(r, one, n, twos, 0, 0, &list)) {
+               free_commit_list(list);
+               return NULL;
+       }
 
        while (list) {
                struct commit *commit = pop_commit(&list);
@@ -204,7 +211,7 @@ static int remove_redundant_no_gen(struct repository *r,
        for (i = 0; i < cnt; i++)
                repo_parse_commit(r, array[i]);
        for (i = 0; i < cnt; i++) {
-               struct commit_list *common;
+               struct commit_list *common = NULL;
                timestamp_t min_generation = commit_graph_generation(array[i]);
 
                if (redundant[i])
@@ -220,8 +227,16 @@ static int remove_redundant_no_gen(struct repository *r,
                        if (curr_generation < min_generation)
                                min_generation = curr_generation;
                }
-               common = paint_down_to_common(r, array[i], filled,
-                                             work, min_generation, 0);
+               if (paint_down_to_common(r, array[i], filled,
+                                        work, min_generation, 0, &common)) {
+                       clear_commit_marks(array[i], all_flags);
+                       clear_commit_marks_many(filled, work, all_flags);
+                       free_commit_list(common);
+                       free(work);
+                       free(redundant);
+                       free(filled_index);
+                       return -1;
+               }
                if (array[i]->object.flags & PARENT2)
                        redundant[i] = 1;
                for (j = 0; j < filled; j++)
@@ -421,6 +436,10 @@ static struct commit_list *get_merge_bases_many_0(struct repository *r,
        clear_commit_marks_many(n, twos, all_flags);
 
        cnt = remove_redundant(r, rslt, cnt);
+       if (cnt < 0) {
+               free(rslt);
+               return NULL;
+       }
        result = NULL;
        for (i = 0; i < cnt; i++)
                commit_list_insert_by_date(rslt[i], &result);
@@ -490,7 +509,7 @@ int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
                             int nr_reference, struct commit **reference,
                             int ignore_missing_commits)
 {
-       struct commit_list *bases;
+       struct commit_list *bases = NULL;
        int ret = 0, i;
        timestamp_t generation, max_generation = GENERATION_NUMBER_ZERO;
 
@@ -509,10 +528,11 @@ int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
        if (generation > max_generation)
                return ret;
 
-       bases = paint_down_to_common(r, commit,
-                                    nr_reference, reference,
-                                    generation, ignore_missing_commits);
-       if (commit->object.flags & PARENT2)
+       if (paint_down_to_common(r, commit,
+                                nr_reference, reference,
+                                generation, ignore_missing_commits, &bases))
+               ret = -1;
+       else if (commit->object.flags & PARENT2)
                ret = 1;
        clear_commit_marks(commit, all_flags);
        clear_commit_marks_many(nr_reference, reference, all_flags);
@@ -565,6 +585,10 @@ struct commit_list *reduce_heads(struct commit_list *heads)
                }
        }
        num_head = remove_redundant(the_repository, array, num_head);
+       if (num_head < 0) {
+               free(array);
+               return NULL;
+       }
        for (i = 0; i < num_head; i++)
                tail = &commit_list_insert(array[i], tail)->next;
        free(array);