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[24.132.57.224]) by smtp.gmail.com with ESMTPSA id ia26sm10658124ejc.73.2021.07.01.05.05.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Jul 2021 05:05:53 -0700 (PDT) From: =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason To: Han-Wen Nienhuys via GitGitGadget Cc: git@vger.kernel.org, Jonathan Tan , Han-Wen Nienhuys , Han-Wen Nienhuys Subject: Re: [PATCH v2 5/8] refs: use refs_resolve_ref_unsafe_with_errno() where needed Date: Thu, 01 Jul 2021 13:58:35 +0200 References: <005ee8e6fb2a0f1a38801bed1dfe082999bfec14.1623329869.git.gitgitgadget@gmail.com> User-agent: Debian GNU/Linux 11 (bullseye); Emacs 27.1; mu4e 1.5.13 In-reply-to: <005ee8e6fb2a0f1a38801bed1dfe082999bfec14.1623329869.git.gitgitgadget@gmail.com> Message-ID: <87bl7mdysf.fsf@evledraar.gmail.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Thu, Jun 10 2021, Han-Wen Nienhuys via GitGitGadget wrote: > From: Han-Wen Nienhuys > > lock_ref_oid_basic() in files-backend.c is the only caller of refs_resolve_ref() > that needs error information to make logic decisions. > > Signed-off-by: Han-Wen Nienhuys > Reviewed-by: Jonathan Tan > --- > refs/files-backend.c | 19 ++++++++++--------- > 1 file changed, 10 insertions(+), 9 deletions(-) > > diff --git a/refs/files-backend.c b/refs/files-backend.c > index 8f969c8f711f..5a430aabf623 100644 > --- a/refs/files-backend.c > +++ b/refs/files-backend.c > @@ -924,6 +924,7 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, > int mustexist = (old_oid && !is_null_oid(old_oid)); > int resolve_flags = RESOLVE_REF_NO_RECURSE; > int resolved; > + int resolve_errno = 0; > > files_assert_main_repository(refs, "lock_ref_oid_basic"); > assert(err); > @@ -936,10 +937,11 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, > resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME; > > files_ref_path(refs, &ref_file, refname); > - resolved = !!refs_resolve_ref_unsafe(&refs->base, > - refname, resolve_flags, > - &lock->old_oid, type); > - if (!resolved && errno == EISDIR) { > + resolved = !!refs_resolve_ref_unsafe_with_errno(&refs->base, refname, > + resolve_flags, > + &lock->old_oid, type, > + &resolve_errno); > + if (!resolved && resolve_errno == EISDIR) { > /* > * we are trying to lock foo but we used to > * have foo/bar which now does not exist; > @@ -959,12 +961,11 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, > &lock->old_oid, type); > } > 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)) > strbuf_addf(err, "unable to resolve reference '%s': %s", > - refname, strerror(last_errno)); > + refname, strerror(resolve_errno)); > > goto error_return; > } So, having read 4/8 and this I wonder why refs_resolve_ref_unsafe_with_errno() is needed at all. It's just a wrapper that sets errno to a variable you give it, but we could just document that tha caller should check errno. So far I haven't seen anything that suggests the below diff-on-top wouldn't be OK (and all tests pass with it). It steps on the toes of some of my earlier suggestions, but I'm doing these one-at-a-time. In any case the comment I adjusted seems like something you should adjust to. It looks like a TODO for having the sort of function you've just implemented in refs_resolve_ref_unsafe_with_errno(). diff --git a/refs.c b/refs.c index 64e2d55adcf..a07d852fcdc 100644 --- a/refs.c +++ b/refs.c @@ -1688,7 +1688,10 @@ int refs_read_raw_ref(struct ref_store *ref_store, return result; } -/* This function needs to return a meaningful errno on failure */ +/* + * This function clears errno at the beginning. If it fails the errno + * will be meaningful. + */ const char *refs_resolve_ref_unsafe(struct ref_store *refs, const char *refname, int resolve_flags, @@ -1698,6 +1701,7 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs, struct object_id unused_oid; int unused_flags; int symref_count; + errno = 0; if (!oid) oid = &unused_oid; @@ -1781,18 +1785,6 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs, return NULL; } -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) -{ - const char *result = refs_resolve_ref_unsafe(refs, refname, - resolve_flags, oid, flags); - *failure_errno = errno; - return result; -} - /* backend functions */ int refs_init_db(struct strbuf *err) { diff --git a/refs/files-backend.c b/refs/files-backend.c index 5a430aabf62..5a400e55cbf 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -924,7 +924,6 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, int mustexist = (old_oid && !is_null_oid(old_oid)); int resolve_flags = RESOLVE_REF_NO_RECURSE; int resolved; - int resolve_errno = 0; files_assert_main_repository(refs, "lock_ref_oid_basic"); assert(err); @@ -937,11 +936,10 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME; files_ref_path(refs, &ref_file, refname); - resolved = !!refs_resolve_ref_unsafe_with_errno(&refs->base, refname, - resolve_flags, - &lock->old_oid, type, - &resolve_errno); - if (!resolved && resolve_errno == EISDIR) { + resolved = !!refs_resolve_ref_unsafe(&refs->base, refname, + resolve_flags, + &lock->old_oid, type); + if (!resolved && errno == EISDIR) { /* * we are trying to lock foo but we used to * have foo/bar which now does not exist; @@ -961,11 +959,11 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, &lock->old_oid, type); } if (!resolved) { - if (resolve_errno != ENOTDIR || + if (errno != ENOTDIR || !refs_verify_refname_available(&refs->base, refname, extras, skip, err)) strbuf_addf(err, "unable to resolve reference '%s': %s", - refname, strerror(resolve_errno)); + refname, strerror(errno)); goto error_return; }