v5 * address Ævar's comment; punt on clearing errno. Han-Wen Nienhuys (5): refs: remove EINVAL errno output from specification of read_raw_ref_fn refs/files-backend: stop setting errno from lock_ref_oid_basic refs: make errno output explicit for read_raw_ref_fn refs: add failure_errno to refs_read_raw_ref() signature refs: make errno output explicit for refs_resolve_ref_unsafe refs.c | 52 ++++++++++++++++++++++++++----------- refs/debug.c | 4 +-- refs/files-backend.c | 60 ++++++++++++++++++++----------------------- refs/packed-backend.c | 15 ++++++----- refs/refs-internal.h | 34 ++++++++++++++++-------- 5 files changed, 98 insertions(+), 67 deletions(-) base-commit: 670b81a890388c60b7032a4f5b879f2ece8c4558 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1012%2Fhanwen%2Feinval-sideband-v3 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1012/hanwen/einval-sideband-v3 Pull-Request: https://github.com/git/git/pull/1012 Range-diff vs v2: 1: f9b92e62b59 = 1: e2a0e5387ab refs: remove EINVAL errno output from specification of read_raw_ref_fn 2: cbe09a48036 ! 2: c594c9c5c67 refs/files-backend: stop setting errno from lock_ref_oid_basic @@ Commit message Signed-off-by: Han-Wen Nienhuys <hanwen@xxxxxxxxxx> Reviewed-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx> + Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> ## refs/files-backend.c ## @@ refs/files-backend.c: static int create_reflock(const char *path, void *cb) @@ refs/files-backend.c: static struct ref_lock *lock_ref_oid_basic(struct files_re - last_errno = errno; + int last_errno = errno; if (last_errno != ENOTDIR || - !refs_verify_refname_available(&refs->base, refname, - extras, skip, err)) +- !refs_verify_refname_available(&refs->base, refname, +- extras, skip, err)) ++ /* in case of D/F conflict, try to generate a better error ++ * message. If that fails, fall back to strerror(ENOTDIR). ++ */ ++ !refs_verify_refname_available(&refs->base, refname, extras, ++ skip, err)) + strbuf_addf(err, "unable to resolve reference '%s': %s", + refname, strerror(last_errno)); + @@ refs/files-backend.c: static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, if (is_null_oid(&lock->old_oid) && refs_verify_refname_available(refs->packed_ref_store, refname, 3: 3e2831e59c8 ! 3: b017caf54ba refs: make errno output explicit for read_raw_ref_fn @@ Metadata ## Commit message ## refs: make errno output explicit for read_raw_ref_fn + This makes it explicit how alternative ref backends should report errors in + read_raw_ref_fn. + read_raw_ref_fn needs to supply a credible errno for a number of cases. These are primarily: @@ Commit message Signed-off-by: Han-Wen Nienhuys <hanwen@xxxxxxxxxx> Reviewed-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx> + Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> ## refs.c ## @@ refs.c: int refs_read_raw_ref(struct ref_store *ref_store, const char *refname, struct object_id *oid, struct strbuf *referent, unsigned int *type) { -+ int result, failure; ++ int result; ++ int failure_errno; if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) { return refs_read_special_head(ref_store, refname, oid, referent, type); @@ refs.c: int refs_read_raw_ref(struct ref_store *ref_store, - return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, - type); -+ failure = 0; ++ failure_errno = 0; + result = ref_store->be->read_raw_ref(ref_store, refname, oid, referent, -+ type, &failure); -+ errno = failure; ++ type, &failure_errno); ++ if (failure_errno) ++ errno = failure_errno; + return result; } @@ refs/files-backend.c: stat_ref: out: - save_errno = errno; -+ if (failure_errno) -+ *failure_errno = errno; ++ *failure_errno = errno; strbuf_release(&sb_path); strbuf_release(&sb_contents); - errno = save_errno; @@ refs/refs-internal.h: typedef int reflog_expire_fn(struct ref_store *ref_store, - * an object ID, it is broken; set REF_ISBROKEN in type, and return -1 - * (errno should not be ENOENT) If there is another error reading the - * ref, set errno appropriately and return -1. -+ * Return 0 on success. If the ref doesn't exist, set failure_errno to ENOENT -+ * and return -1. If the ref exists but is neither a symbolic ref nor an object -+ * ID, it is broken; set REF_ISBROKEN in type, and return -1 (failure_errno -+ * should not be ENOENT). The files backend may return EISDIR (if the ref name -+ * is a directory) and ENOTDIR (if a ref prefix is not a directory). If there is -+ * another error reading the ref, set failure_errno appropriately and return -1. ++ * Return 0 on success, or -1 on failure. If the ref exists but is neither a ++ * symbolic ref nor an object ID, it is broken. In this case set REF_ISBROKEN in ++ * type, and return -1 (failure_errno should not be ENOENT) ++ * ++ * failure_errno provides errno codes that are interpreted beyond error ++ * reporting. The following error codes have special meaning: ++ * * ENOENT: the ref doesn't exist ++ * * EISDIR: ref name is a directory ++ * * ENOTDIR: ref prefix is not a directory * * Backend-specific flags might be set in type as well, regardless of * outcome. 4: 11b2184044d < -: ----------- refs: make errno output explicit for refs_resolve_ref_unsafe 6: 2b346caf1ae ! 4: 4aaa9d3bd6f refs: add failure_errno to refs_read_raw_ref() signature @@ Metadata ## Commit message ## refs: add failure_errno to refs_read_raw_ref() signature - This makes the errno output of refs_read_raw_ref explicit. + This lets us use the explicit errno output parameter in refs_resolve_ref_unsafe. Signed-off-by: Han-Wen Nienhuys <hanwen@xxxxxxxxxx> Reviewed-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx> + Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> ## refs.c ## @@ refs.c: done: @@ refs.c: done: + struct object_id *oid, struct strbuf *referent, + unsigned int *type, int *failure_errno) { -- int result, failure; +- int result; +- int failure_errno; ++ int ignore; + if (failure_errno) + *failure_errno = 0; ++ else ++ failure_errno = &ignore; ++ if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) { return refs_read_special_head(ref_store, refname, oid, referent, type); } -- failure = 0; +- failure_errno = 0; - result = ref_store->be->read_raw_ref(ref_store, refname, oid, referent, -- type, &failure); -- errno = failure; +- type, &failure_errno); +- if (failure_errno) +- errno = failure_errno; - return result; + return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, + type, failure_errno); } - /* This function needs to return a meaningful errno on failure */ +-/* This function needs to return a meaningful errno on failure */ +-const char *refs_resolve_ref_unsafe(struct ref_store *refs, +- const char *refname, +- int resolve_flags, +- struct object_id *oid, int *flags) ++const char *refs_resolve_ref_unsafe_with_errno(struct ref_store *refs, ++ const char *refname, ++ int resolve_flags, ++ struct object_id *oid, ++ int *flags, int *failure_errno) + { + static struct strbuf sb_refname = STRBUF_INIT; + struct object_id unused_oid; + int unused_flags; ++ int unused_errno; + int symref_count; + + if (!oid) +@@ refs.c: const char *refs_resolve_ref_unsafe(struct ref_store *refs, + flags = &unused_flags; + + *flags = 0; ++ if (!failure_errno) ++ failure_errno = &unused_errno; ++ *failure_errno = 0; + + if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) { + if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) || @@ refs.c: const char *refs_resolve_ref_unsafe(struct ref_store *refs, for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) { @@ refs.c: const char *refs_resolve_ref_unsafe(struct ref_store *refs, + &read_flags, &read_failure)) { *flags |= read_flags; ++ *failure_errno = read_failure; ++ /* In reading mode, refs must eventually resolve */ + if (resolve_flags & RESOLVE_REF_READING) + return NULL; @@ refs.c: const char *refs_resolve_ref_unsafe(struct ref_store *refs, * may show errors besides ENOENT if there are * similarly-named refs. @@ refs.c: const char *refs_resolve_ref_unsafe(struct ref_store *refs, return NULL; oidclr(oid); +@@ refs.c: const char *refs_resolve_ref_unsafe(struct ref_store *refs, + return NULL; + } + ++const char *refs_resolve_ref_unsafe(struct ref_store *refs, const char *refname, ++ int resolve_flags, struct object_id *oid, ++ int *flags) ++{ ++ int ignore = 0; ++ return refs_resolve_ref_unsafe_with_errno(refs, refname, resolve_flags, ++ oid, flags, &ignore); ++} ++ + /* backend functions */ + int refs_init_db(struct strbuf *err) + { @@ refs.c: int refs_verify_refname_available(struct ref_store *refs, if (skip && string_list_has_string(skip, dirname.buf)) continue; @@ refs/files-backend.c: stat_ref: } ## refs/packed-backend.c ## -@@ refs/packed-backend.c: static int packed_read_raw_ref(struct ref_store *ref_store, const char *refname, - - if (!rec) { - /* refname is not a packed reference. */ -- *failure_errno = ENOENT; -+ if (failure_errno) -+ *failure_errno = ENOENT; - return -1; - } - @@ refs/packed-backend.c: int is_packed_transaction_needed(struct ref_store *ref_store, ret = 0; for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; -+ int failure; ++ int failure_errno = 0; unsigned int type; struct object_id oid; @@ refs/packed-backend.c: int is_packed_transaction_needed(struct ref_store *ref_st - &oid, &referent, &type) || - errno != ENOENT) { + if (!refs_read_raw_ref(ref_store, update->refname, &oid, -+ &referent, &type, &failure) || -+ failure != ENOENT) { ++ &referent, &type, &failure_errno) || ++ failure_errno != ENOENT) { /* * We have to actually delete that reference * -> this transaction is needed. @@ refs/refs-internal.h: struct ref_update { + struct object_id *oid, struct strbuf *referent, + unsigned int *type, int *failure_errno); - /* Like refs_resolve_ref_unsafe, but provide access to errno code that lead to a - * failure. */ + /* + * Write an error to `err` and return a nonzero value iff the same 5: 005ee8e6fb2 ! 5: ed5347d7bb6 refs: use refs_resolve_ref_unsafe_with_errno() where needed @@ Metadata Author: Han-Wen Nienhuys <hanwen@xxxxxxxxxx> ## Commit message ## - refs: use refs_resolve_ref_unsafe_with_errno() where needed + refs: make errno output explicit for refs_resolve_ref_unsafe + + This introduces refs_resolve_ref_unsafe_with_errno(), which makes the API + contract for the errno output explicit. The implementation still relies on + the global errno variable to ensure no side effects of this refactoring. lock_ref_oid_basic() in files-backend.c is the only caller of refs_resolve_ref() - that needs error information to make logic decisions. + that needs error information to make logic decisions, so update that caller Signed-off-by: Han-Wen Nienhuys <hanwen@xxxxxxxxxx> Reviewed-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx> + Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> ## refs/files-backend.c ## @@ refs/files-backend.c: static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, @@ refs/files-backend.c: static struct ref_lock *lock_ref_oid_basic(struct files_re if (!resolved) { - int last_errno = errno; - if (last_errno != ENOTDIR || -- !refs_verify_refname_available(&refs->base, refname, -- extras, skip, err)) + if (resolve_errno != ENOTDIR || -+ !refs_verify_refname_available(&refs->base, refname, extras, -+ skip, err)) + /* in case of D/F conflict, try to generate a better error + * message. If that fails, fall back to strerror(ENOTDIR). + */ + !refs_verify_refname_available(&refs->base, refname, extras, + skip, err)) strbuf_addf(err, "unable to resolve reference '%s': %s", - refname, strerror(last_errno)); + refname, strerror(resolve_errno)); goto error_return; } + + ## refs/refs-internal.h ## +@@ refs/refs-internal.h: int refs_read_raw_ref(struct ref_store *ref_store, const char *refname, + struct object_id *oid, struct strbuf *referent, + unsigned int *type, int *failure_errno); + ++/* Like refs_resolve_ref_unsafe, but provide access to errno code that lead to a ++ * failure. */ ++const char *refs_resolve_ref_unsafe_with_errno(struct ref_store *refs, ++ const char *refname, ++ int resolve_flags, ++ struct object_id *oid, ++ int *flags, int *failure_errno); ++ + /* + * Write an error to `err` and return a nonzero value iff the same + * refname appears multiple times in `refnames`. `refnames` must be 7: d8651621968 < -: ----------- refs: clear errno return in refs_resolve_ref_unsafe() 8: 2a9ebe43dea < -: ----------- refs: explicitly propagate errno from refs_read_raw_ref -- gitgitgadget
