On Dec 18, 2014, at 2:18 PM, Junio C Hamano <gitster@xxxxxxxxx> wrote:
> Kenneth Lorber <keni@xxxxxxx> writes:
>
>>> Bug: exit codes from (at least) internal commands are handled incorrectly.
>>> E.g. git-merge-file, docs say:
>>> The exit value of this program is negative on error, and the number of
>>> conflicts otherwise. If the merge was clean, the exit value is 0.
>>> But only 8 bits get carried through exit, so 256 conflicts gives
>>> exit(0), which means the merge was clean.
>
> Wouldn't any cmd_foo() that returns negative to main() be buggy?
Yes.
>
> Your change sweeps such problems under the rug, which is not a
> healthy thing to do.
Agreed. (See below.)
>
> Expecting that the exit code can signal small positive integers and
> other generic kinds of failures is a losing proposition. I think it
> is a better fix to update cmd_merge_file() to return 1 (when ret is
> positive), 0 (when ret is zero) or 128 (when ret is negative), or
> something simple like that, and update the documentation to match
> that, without touching git.c::main().
The new patch uses 0, 1, and 2 to match diff(1).
> Among the in-tree users, I notice git-cvsserver.perl is already
> using the command incorrectly. It does this:
>
> my $return = system("git", "merge-file", $file_local, $file_old, $file_new);
> $return >>= 8;
>
> cleanupTmpDir();
>
> if ( $return == 0 )
> {
> $log->info("Merged successfully");
> ...
> }
> elsif ( $return == 1 )
> {
> $log->info("Merged with conflicts");
> ...
> }
> else
> {
> $log->warn("Merge failed");
> next;
> }
>
> which assumes $return == 1 is special "half-good", which is not
> consistent with the documented interface. It will incorrectly
> say "Merge failed" when there are two or more conflicts.
>
> And with such a "1 or 0 or -1" change, you will fix that caller as
> well ;-)
I'll call that a win.
The attached patch covers the following:
- fixes all places where "make test" attempts to call exit() with a value <0 or >255
- changes git-merge-file.txt to reflect the change in exit codes
- fixes the exit codes for merge-file
- adds a warning (which should probably be changed to something clearer) if git.c:run_builtin() is going to cause an out-of-bounds exit
- fixes a typo in t7007-show.sh
- replaces return(0) with exit(0) in test-parse-options.c
The diff is cut against 15598cf41beed0d86cd2ac443e0f69c5a3b40321 (2.3.0-rc2)
Thanks,
Keni
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