From: John Cai Date: Tue, 05 Mar 2024 20:56:03 GMT Subject: Re: [PATCH] show-ref: add --unresolved option Message-ID: <44609CA3-1215-4EAD-8456-DDD66A3B93A8@gmail.com> In-Reply-To: Hi Junio, On 4 Mar 2024, at 18:23, Junio C Hamano wrote: > "John Cai via GitGitGadget" writes: > >> From: John Cai >> >> For reftable development, it would be handy to have a tool to provide >> the direct value of any ref whether it be a symbolic ref or not. >> Currently there is git-symbolic-ref, which only works for symbolic refs, >> and git-rev-parse, which will resolve the ref. Let's add a --unresolved >> option that will only take one ref and return whatever it points to >> without dereferencing it. > > The approach may be reasonble, but the above description can use > some improvements. > > * Even though the title of the patch says show-ref, the last > sentence is a bit too far from there and it was unclear to what > you are adding a new feature at least to me during my first read. > > Let's teach show-ref a `--unresolved` optionthat will ... > > may make it easier to follow. > > * "Whatever it points to without dereferencing it" implied that it > assumes what it is asked to show can be dereferenced, which > invites a natural question: what happens to a thing that is not > dereferenceable in the first place? The implementation seems to > show either symbolic-ref target (for symbolic refs) or the object > name (for others), but let's make it easier for readers. Yeah good point. The language could be made more precise. > >> Documentation/git-show-ref.txt | 8 ++++++ >> builtin/show-ref.c | 33 ++++++++++++++++-------- >> t/t1403-show-ref.sh | 47 ++++++++++++++++++++++++++++++++++ >> 3 files changed, 77 insertions(+), 11 deletions(-) >> >> diff --git a/Documentation/git-show-ref.txt b/Documentation/git-show-ref.txt >> index ba757470059..2f9b4de1346 100644 >> --- a/Documentation/git-show-ref.txt >> +++ b/Documentation/git-show-ref.txt >> @@ -16,6 +16,7 @@ SYNOPSIS >> [--] [...] >> 'git show-ref' --exclude-existing[=] >> 'git show-ref' --exists >> +'git show-ref' --unresolved >> >> DESCRIPTION >> ----------- >> @@ -76,6 +77,13 @@ OPTIONS >> it does, 2 if it is missing, and 1 in case looking up the reference >> failed with an error other than the reference being missing. >> >> +--unresolved:: >> + >> + Prints out what the reference points to without resolving it. Returns >> + an exit code of 0 if it does, 2 if it is missing, and 1 in case looking >> + up the reference failed with an error other than the reference being >> + missing. > > Exactly the same issue as in the proposed log message, i.e. what is > printed for what kind of ref is not really clear. > >> -static int cmd_show_ref__exists(const char **refs) >> +static int cmd_show_ref__raw(const char **refs, int show) >> { >> - struct strbuf unused_referent = STRBUF_INIT; >> - struct object_id unused_oid; >> - unsigned int unused_type; >> + struct strbuf referent = STRBUF_INIT; >> + struct object_id oid; >> + unsigned int type; >> int failure_errno = 0; >> const char *ref; >> int ret = 0; >> @@ -236,7 +237,7 @@ static int cmd_show_ref__exists(const char **refs) >> die("--exists requires exactly one reference"); >> >> if (refs_read_raw_ref(get_main_ref_store(the_repository), ref, >> - &unused_oid, &unused_referent, &unused_type, >> + &oid, &referent, &type, >> &failure_errno)) { >> if (failure_errno == ENOENT || failure_errno == EISDIR) { >> error(_("reference does not exist")); >> @@ -250,8 +251,16 @@ static int cmd_show_ref__exists(const char **refs) >> goto out; >> } >> >> + if (!show) >> + goto out; >> + >> + if (type & REF_ISSYMREF) >> + printf("ref: %s\n", referent.buf); >> + else >> + printf("ref: %s\n", oid_to_hex(&oid)); > > If I create a symbolic ref whose value is deadbeef....deadbeef 40-hex, > I cannot tell from this output if it is a symbolic ref of a ref that > stores an object whose name is that hash. Reserve the use of "ref: %s" > to the symbolic refs (so that it will also match how the files backend > stores them in modern Git), and use some other prefix (or no > perfix). > > Actually, I am not sure if what is proposed is even a good > interface. Given a repository with these few refs: > > $ git show-ref refs/heads/master > b387623c12f3f4a376e4d35a610fd3e55d7ea907 refs/heads/master > $ git show-ref refs/remotes/repo/HEAD > b387623c12f3f4a376e4d35a610fd3e55d7ea907 refs/remotes/repo/HEAD > $ git symbolic-ref refs/remotes/repo/HEAD > refs/remotes/repo/master > > I would think that the second command above shows the gap in feature > set our current "show-ref" has. If we could do > > $ git show-ref --