Re: [PATCH v3] cherry-pick: make sure all input objects are commits
- From
Junio C Hamano <junio@pobox.com>
- Date
- Apr 15, 2013, 19:12 UTC
- Message-ID
- <7v61znsj49.fsf@alter.siamese.dyndns.org>
- In-Reply-To
- <87vc7odvzi.fsf@linux-k42r.v.cablecom.net>
Thomas Rast <trast@inf.ethz.ch> writes:
Show 27 quoted lines
> From a cursory glance it looks like it's actually an existing bug in
> read_revisions_from_stdin or handle_revision_arg, depending on which way
> you look at it. read_revisions_from_stdin passes its temporary buffer
> down to handle_revision_arg:
>
> struct strbuf sb;
> [...]
> strbuf_init(&sb, 1000);
> while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
> [...]
> if (handle_revision_arg(sb.buf, revs, 0, REVARG_CANNOT_BE_FILENAME))
> die("bad revision '%s'", sb.buf);
> }
>
> But handle_revision_arg ends up just stuffing that parameter into the
> revision-walker options via some helpers:
>
> add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
> add_pending_object_with_mode(revs, object, arg, oc.mode);
>
> This seems to have been lurking since 281eee4 (revision: keep track of
> the end-user input from the command line, 2011-08-25).
>
> Junio, at which level should we fix it? We could of course have
> read_revisions_from_stdin make a copy of the buffers it passes down, but
> perhaps it would be less surprising to instead have handle_revision_arg
> make sure it makes a copy of everything it "keeps"?Looking at it again, it seems that the issue is much older than the introduction of cmdline interface.
Everything we throw at add_pending_object() is assumed to be stable, because historically they were argv[] strings, and --stdin is what breaks that assumption. Making copies unconditionally at the lower layer only because some minority callers give it unstable strings does not sound like a good trade-off.
So I changed my mind. Your "easy fix" looks to me the right thing to do.
The paths given to handle_refs() may also have to be copied before saved, depending on how ref iteration is implemented, details of which may change as Michael seems to be updating the area again. I think we let the callback peek ref_entry->name[] which is stable, so I suspect we are OK.
Show 16 quoted lines
> The easy fix of course is just this:
>
> diff --git i/revision.c w/revision.c
> index 3a20c96..181a8db 100644
> --- i/revision.c
> +++ w/revision.c
> @@ -1277,7 +1277,8 @@ static void read_revisions_from_stdin(struct rev_info *revs,
> }
> die("options not supported in --stdin mode");
> }
> - if (handle_revision_arg(sb.buf, revs, 0, REVARG_CANNOT_BE_FILENAME))
> + if (handle_revision_arg(xstrdup(sb.buf), revs, 0,
> + REVARG_CANNOT_BE_FILENAME))
> die("bad revision '%s'", sb.buf);
> }
> if (seen_dashdash)