Junio C Hamano <gitster@xxxxxxxxx> writes:
> I like the general direction to move away from errno, which may make
> sense only in the context of files backend (e.g. ENOENT would be
> left in errno, only because the original "loose ref" implementation
> used one file per ref, when a ref we wanted to see did not exist)
> and having other backends use the same errno would not make much
> sense, as it is not the goal to make other backends like reftable
> emulate files backend.
>
> I wonder if in the ideal world, we'd rather want to define our own
> enum, not <errno.h>, that is specific to failure modes of ref API
> functions and signal failures by returning these values (and the
> enum includes 0 as a value to signal success, all other errors are
> negative values).
>
> What I am really getting at is if we need an extra "failure"
> out-parameter-pointer in the internal API. I do not mind if it
> helps the transition to the ideal world, but I offhand do not see if
> we need result and failure as separate variables.
In any case, the change in the function signature helped me catch
that this series invalidates what has been queued on hn/reftable
without updating that topic to align with the new way to handle the
errno (it would have become a silent semantic failure if we instead
encoded the "failure" in the return value).
The following is what I am tentatively using for tonight's
integration when merging this and hn/reftable together to the 'seen'
branch.
Thanks.
refs/reftable-backend.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git c/refs/reftable-backend.c w/refs/reftable-backend.c
index 1aff21adb4..4385d2d6f5 100644
--- c/refs/reftable-backend.c
+++ w/refs/reftable-backend.c
@@ -52,7 +52,8 @@ static struct reftable_stack *stack_for(struct git_reftable_ref_store *store,
static int git_reftable_read_raw_ref(struct ref_store *ref_store,
const char *refname, struct object_id *oid,
struct strbuf *referent,
- unsigned int *type);
+ unsigned int *type,
+ int *failure_errno);
static void clear_reftable_log_record(struct reftable_log_record *log)
{
@@ -376,7 +377,8 @@ static int fixup_symrefs(struct ref_store *ref_store,
&old_oid, &referent,
/* mutate input, like
files-backend.c */
- &update->type);
+ &update->type,
+ &errno);
if (err < 0 && errno == ENOENT &&
is_null_oid(&update->old_oid)) {
err = 0;
@@ -1538,7 +1540,7 @@ static int reftable_error_to_errno(int err)
static int git_reftable_read_raw_ref(struct ref_store *ref_store,
const char *refname, struct object_id *oid,
struct strbuf *referent,
- unsigned int *type)
+ unsigned int *type, int *failure_errno)
{
struct git_reftable_ref_store *refs =
(struct git_reftable_ref_store *)ref_store;
@@ -1560,12 +1562,12 @@ static int git_reftable_read_raw_ref(struct ref_store *ref_store,
err = reftable_stack_read_ref(stack, refname, &ref);
if (err > 0) {
- errno = ENOENT;
+ *failure_errno = ENOENT;
err = -1;
goto done;
}
if (err < 0) {
- errno = reftable_error_to_errno(err);
+ *failure_errno = reftable_error_to_errno(err);
err = -1;
goto done;
}
@@ -1578,7 +1580,7 @@ static int git_reftable_read_raw_ref(struct ref_store *ref_store,
oidread(oid, reftable_ref_record_val1(&ref));
} else {
*type |= REF_ISBROKEN;
- errno = EINVAL;
+ *failure_errno = EINVAL;
err = -1;
}
done:
