| Message ID | 20241009135747.3563204-4-bence@ferdinandy.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v5,1/6] refs_update_symref: atomically record overwritten ref | expand |
Bence Ferdinandy <bence@ferdinandy.com> writes: > /* Naming conflict (for example, the ref names A and A/B conflict). */ > #define TRANSACTION_NAME_CONFLICT -1 > +/* When only creation was requested, but the ref already exists. */ > +#define TRANSACTION_CREATE_EXISTS -2 > /* All other errors. */ > -#define TRANSACTION_GENERIC_ERROR -2 > +#define TRANSACTION_GENERIC_ERROR -3 My initial knee-jerk reaction to the name "CREATE_EXISTS" was that the "CREATE" part is redundant, as the only case that the fact that something exists is a valid reason for an error is when we attempted to create it. EEXIST in errno(3) is not ECREATE_EXIST for the same reason. But let's let it pass; contrasting with the fact that what ought to be named similarly to EISDIR is called NAME_CONFLICT, CREATE_EXISTS is fine. > diff --git a/refs/files-backend.c b/refs/files-backend.c > index 8415f2d020..272ad81315 100644 > --- a/refs/files-backend.c > +++ b/refs/files-backend.c > @@ -2502,14 +2502,18 @@ static int split_symref_update(struct ref_update *update, > static int check_old_oid(struct ref_update *update, struct object_id *oid, > struct strbuf *err) > { > + int ret = TRANSACTION_GENERIC_ERROR; > + > if (!(update->flags & REF_HAVE_OLD) || > oideq(oid, &update->old_oid)) > return 0; > > - if (is_null_oid(&update->old_oid)) > + if (is_null_oid(&update->old_oid)) { > strbuf_addf(err, "cannot lock ref '%s': " > "reference already exists", > ref_update_original_update_refname(update)); > + ret = TRANSACTION_CREATE_EXISTS; > + } > else if (is_null_oid(oid)) > strbuf_addf(err, "cannot lock ref '%s': " > "reference is missing but expected %s", > @@ -2522,7 +2526,7 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid, > oid_to_hex(oid), > oid_to_hex(&update->old_oid)); > > - return -1; > + return ret; > } OK. So if a caller does not care which exact kind of error it got, they will keep working just the way they used to work, and a caller that cares can now check. A nice API enhancement. > @@ -2603,9 +2607,13 @@ static int lock_ref_for_update(struct files_ref_store *refs, > ret = TRANSACTION_GENERIC_ERROR; > goto out; > } > - } else if (check_old_oid(update, &lock->old_oid, err)) { > - ret = TRANSACTION_GENERIC_ERROR; > - goto out; > + } else { > + int checkret; > + checkret = check_old_oid(update, &lock->old_oid, err); > + if (checkret) { > + ret = checkret; > + goto out; > + } > } Likewise; this code is just propagating what check_old_oid() did to its callers. > @@ -2636,9 +2644,13 @@ static int lock_ref_for_update(struct files_ref_store *refs, > update->old_target); > ret = TRANSACTION_GENERIC_ERROR; > goto out; > - } else if (check_old_oid(update, &lock->old_oid, err)) { > - ret = TRANSACTION_GENERIC_ERROR; > - goto out; > + } else { > + int checkret; > + checkret = check_old_oid(update, &lock->old_oid, err); > + if (checkret) { > + ret = checkret; > + goto out; > + } Ditto. > diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c > index 32330b6bc6..c6b25ebac4 100644 > --- a/refs/reftable-backend.c > +++ b/refs/reftable-backend.c > @@ -1206,10 +1206,13 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store, > goto done; > } > } else if ((u->flags & REF_HAVE_OLD) && !oideq(¤t_oid, &u->old_oid)) { > - if (is_null_oid(&u->old_oid)) > + ret = TRANSACTION_NAME_CONFLICT; > + if (is_null_oid(&u->old_oid)) { > strbuf_addf(err, _("cannot lock ref '%s': " > "reference already exists"), > ref_update_original_update_refname(u)); > + ret = TRANSACTION_CREATE_EXISTS; > + } > else if (is_null_oid(¤t_oid)) > strbuf_addf(err, _("cannot lock ref '%s': " > "reference is missing but expected %s"), > @@ -1221,7 +1224,6 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store, > ref_update_original_update_refname(u), > oid_to_hex(¤t_oid), > oid_to_hex(&u->old_oid)); > - ret = -1; > goto done; > } So it remains a little mystery how the ultimate caller uses this new bit of information. Which is OK---the next step seems to have a new condition on the error status.
diff --git a/refs.h b/refs.h index f38616db84..166affbc89 100644 --- a/refs.h +++ b/refs.h @@ -759,8 +759,10 @@ int ref_transaction_verify(struct ref_transaction *transaction, /* Naming conflict (for example, the ref names A and A/B conflict). */ #define TRANSACTION_NAME_CONFLICT -1 +/* When only creation was requested, but the ref already exists. */ +#define TRANSACTION_CREATE_EXISTS -2 /* All other errors. */ -#define TRANSACTION_GENERIC_ERROR -2 +#define TRANSACTION_GENERIC_ERROR -3 /* * Perform the preparatory stages of committing `transaction`. Acquire diff --git a/refs/files-backend.c b/refs/files-backend.c index 8415f2d020..272ad81315 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -2502,14 +2502,18 @@ static int split_symref_update(struct ref_update *update, static int check_old_oid(struct ref_update *update, struct object_id *oid, struct strbuf *err) { + int ret = TRANSACTION_GENERIC_ERROR; + if (!(update->flags & REF_HAVE_OLD) || oideq(oid, &update->old_oid)) return 0; - if (is_null_oid(&update->old_oid)) + if (is_null_oid(&update->old_oid)) { strbuf_addf(err, "cannot lock ref '%s': " "reference already exists", ref_update_original_update_refname(update)); + ret = TRANSACTION_CREATE_EXISTS; + } else if (is_null_oid(oid)) strbuf_addf(err, "cannot lock ref '%s': " "reference is missing but expected %s", @@ -2522,7 +2526,7 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid, oid_to_hex(oid), oid_to_hex(&update->old_oid)); - return -1; + return ret; } /* @@ -2603,9 +2607,13 @@ static int lock_ref_for_update(struct files_ref_store *refs, ret = TRANSACTION_GENERIC_ERROR; goto out; } - } else if (check_old_oid(update, &lock->old_oid, err)) { - ret = TRANSACTION_GENERIC_ERROR; - goto out; + } else { + int checkret; + checkret = check_old_oid(update, &lock->old_oid, err); + if (checkret) { + ret = checkret; + goto out; + } } } else { /* @@ -2636,9 +2644,13 @@ static int lock_ref_for_update(struct files_ref_store *refs, update->old_target); ret = TRANSACTION_GENERIC_ERROR; goto out; - } else if (check_old_oid(update, &lock->old_oid, err)) { - ret = TRANSACTION_GENERIC_ERROR; - goto out; + } else { + int checkret; + checkret = check_old_oid(update, &lock->old_oid, err); + if (checkret) { + ret = checkret; + goto out; + } } /* diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c index 32330b6bc6..c6b25ebac4 100644 --- a/refs/reftable-backend.c +++ b/refs/reftable-backend.c @@ -1206,10 +1206,13 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store, goto done; } } else if ((u->flags & REF_HAVE_OLD) && !oideq(¤t_oid, &u->old_oid)) { - if (is_null_oid(&u->old_oid)) + ret = TRANSACTION_NAME_CONFLICT; + if (is_null_oid(&u->old_oid)) { strbuf_addf(err, _("cannot lock ref '%s': " "reference already exists"), ref_update_original_update_refname(u)); + ret = TRANSACTION_CREATE_EXISTS; + } else if (is_null_oid(¤t_oid)) strbuf_addf(err, _("cannot lock ref '%s': " "reference is missing but expected %s"), @@ -1221,7 +1224,6 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store, ref_update_original_update_refname(u), oid_to_hex(¤t_oid), oid_to_hex(&u->old_oid)); - ret = -1; goto done; }
Currently there is only one special error for transaction, for when there is a naming conflict, all other errors are dumped under a generic error. Add a new special error case for when the caller requests the reference to be updated only when it does not yet exist and the reference actually does exist. Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com> --- Notes: v4: new patch v5: no change refs.h | 4 +++- refs/files-backend.c | 28 ++++++++++++++++++++-------- refs/reftable-backend.c | 6 ++++-- 3 files changed, 27 insertions(+), 11 deletions(-)