On 05/12/16 12:26 AM, Jeff King wrote:
On Sun, Dec 04, 2016 at 11:19:46PM -0800, Junio C Hamano wrote:
- if (no_index)
+ if (no_index) {
/* If this is a no-index diff, just run it and exit there. */
+ startup_info->have_repository = 0;
diff_no_index(&rev, argc, argv);
+ }
This kind of change makes me nervous (partly because I am not seeing
the whole code but only this part of the patch).
Some code may react to "have_repository" being zero and do the right
thing (which I think is what you are using from your previous "we
did one of the three cases" change here), but the codepath that led
to "have_repository" being set to non-zero previously must have done
a lot more than just flipping that field to non-zero, and setting
zero to this field alone would not "undo" what it did.
I _think_ it's OK because the only substantive change would be the
chdir() to the top of the working tree. But that information is carried
through by revs->prefix, which we act on regardless of the value of
startup_info->have_repository when we call prefix_filename().
I agree that it may be an accident waiting to happen, though, as soon as
some buried sub-function needs to care about the distinction.
I wonder if we're better off if we made sure that diff_no_index()
works the same way regardless of the value of "have_repository"
field?
If you mean adding a diffopt flag like "just abbreviate everything to
FALLBACK_DEFAULT_ABBREV even if we're in a repository", and then setting
that in diff_no_index(), I agree that is a lot cleaner.
I'm still not 100% convinced that it's actually the correct behavior,
but at least doing a more contained version wouldn't take away other
functionality like reading config.
I don't have a strong reason for wanting these three cases to behave
identically, I was merely surprised that they don't. I think you
expected them to behave the same as well? I'll withdraw this patch.
Conceptually I do think of "git diff" as having two separate modes, "in
repository" and "out of repository", with the --no-index option forcing
the "out of repository" mode. But maybe there are good reasons why this
isn't accurate, or maybe it doesn't matter that it's not 100% accurate.
In summary, currently all of the three cases are "no index" but only the
first case doesn't "have repository".
Thank you for your thoughtful feedback!