Re: [PATCH] refs: print errno for read_raw_ref if GIT_TRACE_REFS is set - Han-Wen Nienhuys

From: Han-Wen Nienhuys <hanwen@google.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Han-Wen Nienhuys via GitGitGadget <gitgitgadget@gmail.com>,
	git <git@vger.kernel.org>, Han-Wen Nienhuys <hanwenn@gmail.com>
Subject: Re: [PATCH] refs: print errno for read_raw_ref if GIT_TRACE_REFS is set
Date: Tue, 13 Apr 2021 13:58:42 +0200	[thread overview]
Message-ID: <CAFQ2z_MnZOfo4Bt6SsRJnL+F70r9wr_jYSf2KGvcvyX-8PfVRQ@mail.gmail.com> (raw)
In-Reply-To: <xmqq4kgbb2ic.fsf@gitster.g>

On Mon, Apr 12, 2021 at 11:45 PM Junio C Hamano <gitster@pobox.com> wrote:
> > @@ -251,7 +252,9 @@ static int debug_read_raw_ref(struct ref_store *ref_store, const char *refname,
> >               trace_printf_key(&trace_refs, "read_raw_ref: %s: %s (=> %s) type %x: %d\n",
> >                       refname, oid_to_hex(oid), referent->buf, *type, res);
> >       } else {
> > -             trace_printf_key(&trace_refs, "read_raw_ref: %s: %d\n", refname, res);
> > +             trace_printf_key(&trace_refs,
> > +                              "read_raw_ref: %s: %d (errno %d)\n", refname,
> > +                              res, errno);
> >       }
>
> OK.  Between trace_printf_key() and the return of the call to
> read_raw_ref() method of the ref backend is only an "if (res == 0)"
> condition and I do not see anything that might clobber errno.

I don't want to bet on that. Let me send a second round.

> I do wonder if we want strerror(errno) instead of the number, but I
> can go either way (it's just a trace output).

For tracing, it would be most useful if we got the actual symbol (eg.
ENOENT). Is there a way to get at that?

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Han-Wen Nienhuys - Google Munich
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