[PATCH 06/19] reftable/record: don't `BUG()` in `reftable_record_cmp()`
- From
Patrick Steinhardt <ps@pks.im>
- Date
- Jan 27, 2025, 13:04 UTC
- Message-ID
- <20250127-pks-reftable-drop-git-compat-util-v1-6-6e280a564877@pks.im>
- In-Reply-To
- <20250127-pks-reftable-drop-git-compat-util-v1-0-6e280a564877@pks.im>
The refatble library aborts with a bug in case `reftable_record_cmp()` is invoked with two records of differing types. This would cause the program to die without the caller being able to handle the error, which is not something we want in the context of library code. And it ties us to the Git codebase.
Refactor the code such that `reftable_record_cmp()` returns an error code separate from the actual comparison result. This requires us to also adapt some callers up the callchain in a similar fashion.
Signed-off-by: Patrick Steinhardt <ps@pks.im> --- reftable/merged.c | 20 +++++++++++++++----- reftable/pq.c | 36 +++++++++++++++++++++++++++++------- reftable/pq.h | 2 +- reftable/record.c | 10 ++++++---- reftable/record.h | 2 +- t/unit-tests/t-reftable-pq.c | 16 ++++++++++++---- t/unit-tests/t-reftable-record.c | 40 ++++++++++++++++++++++++++++------------ 7 files changed, 92 insertions(+), 34 deletions(-)
diff --git a/reftable/merged.c b/reftable/merged.c index 4156eec07f..563864068c 100644 --- a/reftable/merged.c +++ b/reftable/merged.c @@ -66,8 +66,11 @@ static int merged_iter_seek(struct merged_iter *mi, struct reftable_record *want int err; mi->advance_index = -1; - while (!merged_iter_pqueue_is_empty(mi->pq)) - merged_iter_pqueue_remove(&mi->pq); + while (!merged_iter_pqueue_is_empty(mi->pq)) { + err = merged_iter_pqueue_remove(&mi->pq, NULL); + if (err < 0) + return err; + } for (size_t i = 0; i < mi->subiters_len; i++) { err = iterator_seek(&mi->subiters[i].iter, want); @@ -120,7 +123,9 @@ static int merged_iter_next_entry(struct merged_iter *mi, if (empty) return 1; - entry = merged_iter_pqueue_remove(&mi->pq); + err = merged_iter_pqueue_remove(&mi->pq, &entry); + if (err < 0) + return err; /* One can also use reftable as datacenter-local storage, where the ref @@ -134,11 +139,16 @@ static int merged_iter_next_entry(struct merged_iter *mi, struct pq_entry top = merged_iter_pqueue_top(mi->pq); int cmp; - cmp = reftable_record_cmp(top.rec, entry.rec); + err = reftable_record_cmp(top.rec, entry.rec, &cmp); + if (err < 0) + return err; if (cmp > 0) break; - merged_iter_pqueue_remove(&mi->pq); + err = merged_iter_pqueue_remove(&mi->pq, NULL); + if (err < 0) + return err; + err = merged_iter_advance_subiter(mi, top.index); if (err < 0) return err; diff --git a/reftable/pq.c b/reftable/pq.c index 5591e875e1..ef8035cfd9 100644 --- a/reftable/pq.c +++ b/reftable/pq.c @@ -15,13 +15,18 @@ license that can be found in the LICENSE file or at int pq_less(struct pq_entry *a, struct pq_entry *b) { - int cmp = reftable_record_cmp(a->rec, b->rec); + int cmp, err; + + err = reftable_record_cmp(a->rec, b->rec, &cmp); + if (err < 0) + return err; + if (cmp == 0) return a->index > b->index; return cmp < 0; } -struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq) +int merged_iter_pqueue_remove(struct merged_iter_pqueue *pq, struct pq_entry *out) { size_t i = 0; struct pq_entry e = pq->heap[0]; @@ -32,17 +37,34 @@ struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq) size_t min = i; size_t j = 2 * i + 1; size_t k = 2 * i + 2; - if (j < pq->len && pq_less(&pq->heap[j], &pq->heap[i])) - min = j; - if (k < pq->len && pq_less(&pq->heap[k], &pq->heap[min])) - min = k; + int cmp; + + if (j < pq->len) { + cmp = pq_less(&pq->heap[j], &pq->heap[i]); + if (cmp < 0) + return -1; + else if (cmp) + min = j; + } + + if (k < pq->len) { + cmp = pq_less(&pq->heap[k], &pq->heap[min]); + if (cmp < 0) + return -1; + else if (cmp) + min = k; + } + if (min == i) break; SWAP(pq->heap[i], pq->heap[min]); i = min; } - return e; + if (out) + *out = e; + + return 0; } int merged_iter_pqueue_add(struct merged_iter_pqueue *pq, const struct pq_entry *e) diff --git a/reftable/pq.h b/reftable/pq.h index 83c062eeca..ff39016445 100644 --- a/reftable/pq.h +++ b/reftable/pq.h @@ -22,7 +22,7 @@ struct merged_iter_pqueue { size_t cap; }; -struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq); +int merged_iter_pqueue_remove(struct merged_iter_pqueue *pq, struct pq_entry *out); int merged_iter_pqueue_add(struct merged_iter_pqueue *pq, const struct pq_entry *e); void merged_iter_pqueue_release(struct merged_iter_pqueue *pq); int pq_less(struct pq_entry *a, struct pq_entry *b); diff --git a/reftable/record.c b/reftable/record.c index 31985bb977..da550494a2 100644 --- a/reftable/record.c +++ b/reftable/record.c @@ -1190,12 +1190,14 @@ int reftable_record_is_deletion(struct reftable_record *rec) reftable_record_data(rec)); } -int reftable_record_cmp(struct reftable_record *a, struct reftable_record *b) +int reftable_record_cmp(struct reftable_record *a, struct reftable_record *b, + int *cmp) { if (a->type != b->type) - BUG("cannot compare reftable records of different type"); - return reftable_record_vtable(a)->cmp( - reftable_record_data(a), reftable_record_data(b)); + return -1; + *cmp = reftable_record_vtable(a)->cmp(reftable_record_data(a), + reftable_record_data(b)); + return 0; } int reftable_record_equal(struct reftable_record *a, struct reftable_record *b, uint32_t hash_size) diff --git a/reftable/record.h b/reftable/record.h index e1846c294b..867810a932 100644 --- a/reftable/record.h +++ b/reftable/record.h @@ -134,7 +134,7 @@ struct reftable_record { int reftable_record_init(struct reftable_record *rec, uint8_t typ); /* see struct record_vtable */ -int reftable_record_cmp(struct reftable_record *a, struct reftable_record *b); +int reftable_record_cmp(struct reftable_record *a, struct reftable_record *b, int *cmp); int reftable_record_equal(struct reftable_record *a, struct reftable_record *b, uint32_t hash_size); int reftable_record_key(struct reftable_record *rec, struct reftable_buf *dest); int reftable_record_copy_from(struct reftable_record *rec, diff --git a/t/unit-tests/t-reftable-pq.c b/t/unit-tests/t-reftable-pq.c index d8a4c283a1..c128fe8616 100644 --- a/t/unit-tests/t-reftable-pq.c +++ b/t/unit-tests/t-reftable-pq.c @@ -21,7 +21,9 @@ static void merged_iter_pqueue_check(const struct merged_iter_pqueue *pq) static int pq_entry_equal(struct pq_entry *a, struct pq_entry *b) { - return !reftable_record_cmp(a->rec, b->rec) && (a->index == b->index); + int cmp; + check(!reftable_record_cmp(a->rec, b->rec, &cmp)); + return !cmp && (a->index == b->index); } static void t_pq_record(void) @@ -49,7 +51,9 @@ static void t_pq_record(void) while (!merged_iter_pqueue_is_empty(pq)) { struct pq_entry top = merged_iter_pqueue_top(pq); - struct pq_entry e = merged_iter_pqueue_remove(&pq); + struct pq_entry e; + + check(!merged_iter_pqueue_remove(&pq, &e)); merged_iter_pqueue_check(&pq); check(pq_entry_equal(&top, &e)); @@ -90,7 +94,9 @@ static void t_pq_index(void) for (i = N - 1; i > 0; i--) { struct pq_entry top = merged_iter_pqueue_top(pq); - struct pq_entry e = merged_iter_pqueue_remove(&pq); + struct pq_entry e; + + check(!merged_iter_pqueue_remove(&pq, &e)); merged_iter_pqueue_check(&pq); check(pq_entry_equal(&top, &e)); @@ -129,7 +135,9 @@ static void t_merged_iter_pqueue_top(void) for (i = N - 1; i > 0; i--) { struct pq_entry top = merged_iter_pqueue_top(pq); - struct pq_entry e = merged_iter_pqueue_remove(&pq); + struct pq_entry e; + + check(!merged_iter_pqueue_remove(&pq, &e)); merged_iter_pqueue_check(&pq); check(pq_entry_equal(&top, &e)); diff --git a/t/unit-tests/t-reftable-record.c b/t/unit-tests/t-reftable-record.c index 6540bd20e3..5954966373 100644 --- a/t/unit-tests/t-reftable-record.c +++ b/t/unit-tests/t-reftable-record.c @@ -100,16 +100,20 @@ static void t_reftable_ref_record_comparison(void) .u.ref.value.symref = (char *) "refs/heads/master", }, }; + int cmp; check(!reftable_record_equal(&in[0], &in[1], REFTABLE_HASH_SIZE_SHA1)); - check(!reftable_record_cmp(&in[0], &in[1])); + check(!reftable_record_cmp(&in[0], &in[1], &cmp)); + check(!cmp); check(!reftable_record_equal(&in[1], &in[2], REFTABLE_HASH_SIZE_SHA1)); - check_int(reftable_record_cmp(&in[1], &in[2]), >, 0); + check(!reftable_record_cmp(&in[1], &in[2], &cmp)); + check_int(cmp, >, 0); in[1].u.ref.value_type = in[0].u.ref.value_type; check(reftable_record_equal(&in[0], &in[1], REFTABLE_HASH_SIZE_SHA1)); - check(!reftable_record_cmp(&in[0], &in[1])); + check(!reftable_record_cmp(&in[0], &in[1], &cmp)); + check(!cmp); } static void t_reftable_ref_record_compare_name(void) @@ -209,17 +213,20 @@ static void t_reftable_log_record_comparison(void) .u.log.update_index = 22, }, }; + int cmp; check(!reftable_record_equal(&in[0], &in[1], REFTABLE_HASH_SIZE_SHA1)); check(!reftable_record_equal(&in[1], &in[2], REFTABLE_HASH_SIZE_SHA1)); - check_int(reftable_record_cmp(&in[1], &in[2]), >, 0); + check(!reftable_record_cmp(&in[1], &in[2], &cmp)); + check_int(cmp, >, 0); /* comparison should be reversed for equal keys, because * comparison is now performed on the basis of update indices */ - check_int(reftable_record_cmp(&in[0], &in[1]), <, 0); + check(!reftable_record_cmp(&in[0], &in[1], &cmp)); + check_int(cmp, <, 0); in[1].u.log.update_index = in[0].u.log.update_index; check(reftable_record_equal(&in[0], &in[1], REFTABLE_HASH_SIZE_SHA1)); - check(!reftable_record_cmp(&in[0], &in[1])); + check(!reftable_record_cmp(&in[0], &in[1], &cmp)); } static void t_reftable_log_record_compare_key(void) @@ -396,16 +403,20 @@ static void t_reftable_obj_record_comparison(void) .u.obj.hash_prefix_len = 5, }, }; + int cmp; check(!reftable_record_equal(&in[0], &in[1], REFTABLE_HASH_SIZE_SHA1)); - check(!reftable_record_cmp(&in[0], &in[1])); + check(!reftable_record_cmp(&in[0], &in[1], &cmp)); + check(!cmp); check(!reftable_record_equal(&in[1], &in[2], REFTABLE_HASH_SIZE_SHA1)); - check_int(reftable_record_cmp(&in[1], &in[2]), >, 0); + check(!reftable_record_cmp(&in[1], &in[2], &cmp)); + check_int(cmp, >, 0); in[1].u.obj.offset_len = in[0].u.obj.offset_len; check(reftable_record_equal(&in[0], &in[1], REFTABLE_HASH_SIZE_SHA1)); - check(!reftable_record_cmp(&in[0], &in[1])); + check(!reftable_record_cmp(&in[0], &in[1], &cmp)); + check(!cmp); } static void t_reftable_obj_record_roundtrip(void) @@ -486,19 +497,24 @@ static void t_reftable_index_record_comparison(void) .u.idx.last_key = REFTABLE_BUF_INIT, }, }; + int cmp; + check(!reftable_buf_addstr(&in[0].u.idx.last_key, "refs/heads/master")); check(!reftable_buf_addstr(&in[1].u.idx.last_key, "refs/heads/master")); check(!reftable_buf_addstr(&in[2].u.idx.last_key, "refs/heads/branch")); check(!reftable_record_equal(&in[0], &in[1], REFTABLE_HASH_SIZE_SHA1)); - check(!reftable_record_cmp(&in[0], &in[1])); + check(!reftable_record_cmp(&in[0], &in[1], &cmp)); + check(!cmp); check(!reftable_record_equal(&in[1], &in[2], REFTABLE_HASH_SIZE_SHA1)); - check_int(reftable_record_cmp(&in[1], &in[2]), >, 0); + check(!reftable_record_cmp(&in[1], &in[2], &cmp)); + check_int(cmp, >, 0); in[1].u.idx.offset = in[0].u.idx.offset; check(reftable_record_equal(&in[0], &in[1], REFTABLE_HASH_SIZE_SHA1)); - check(!reftable_record_cmp(&in[0], &in[1])); + check(!reftable_record_cmp(&in[0], &in[1], &cmp)); + check(!cmp); for (size_t i = 0; i < ARRAY_SIZE(in); i++) reftable_record_release(&in[i]);
-- 2.48.1.362.g079036d154.dirty