On Thu, Jun 13, 2019 at 03:15:41PM -0700, Emily Shaffer wrote: > I thought this was odd when I was working on the other rev-list changes > - --abbrev doesn't do anything on its own. It looks like it does work by > itself in other commands, but apparently not in rev-list. > > Listed this patch as RFC because maybe instead it's better to fix > something so --abbrev can be used alone, or teach --abbrev-commit=<n>. > It looks like `git log --abbrev=5` also doesn't work the way one might > expect, which makes sense to me, as they use the same internals for > option parsing (parse_revisions()). > > The manpages for log and rev-list both correctly indicate that > --abbrev=<n> is an optional addition to --abbrev-commit. `git log -h` is > generated by parse-options tooling and doesn't cover --abbrev-commit at > all, but `git rev-list` doesn't use an option parser on its own and the > usage is hardcoded. Yeah, "--abbrev" is a bit tricky here. It is really "when you abbrev, do it to this level". In "log", that means that "git log --abbrev=5 --raw" _does_ do something useful (it abbreviates the blob hashes). And then you may add "--abbrev-commit" on top to ask to abbreviate the commit ids. And rev-list follows that same pattern, except that rev-list _never_ shows diff output. You'd traditionally do (and this is how log was implemented once upon a time): git rev-list HEAD | git diff-tree --stdin --abbrev=5 --raw But even there, we are not seeing the commit id output by rev-list. It goes to diff-tree, which then formats it separately. So if you wanted abbreviated commits there, you'd add "--abbrev-commit" to the diff-tree invocation, not rev-list! So no, I cannot see a way in which "rev-list --abbrev" is useful without "--abbrev-commit". Which means that perhaps the former should imply the latter. And as you noticed in your other patch, there is no way to abbreviate "--objects" output at all. I am not sure I have ever seen a good use for that. Though to be honest, I am not sure that "--abbrev" is really all that useful in the first place. Machine-readable output should never abbreviate, and human-readable ones generally already do. But at any rate, before making any behavior changes it may make sense to think about how they'd interact with "rev-list --objects" abbreviation, if it were to be added. As for the patch itself: > diff --git a/builtin/rev-list.c b/builtin/rev-list.c > index 9f31837d30..6ae0087b01 100644 > --- a/builtin/rev-list.c > +++ b/builtin/rev-list.c > @@ -49,8 +49,8 @@ static const char rev_list_usage[] = > " --objects | --objects-edge\n" > " --unpacked\n" > " --header | --pretty\n" > -" --abbrev=<n> | --no-abbrev\n" > -" --abbrev-commit\n" > +" --abbrev-commit [--abbrev=<n>]\n" > +" --no-abbrev\n" So --no-abbrev clears both --abbrev and --abbrev-commit. That sort of makes sense, though I did not expect it. But it also means that: --abbrev-commit [--abbrev=<n> | --no-abbrev] is not right. Possibly: --abbrev-commit [--abbrev=<n>] | --no-abbrev would show the interaction more clearly, but I don't have a strong opinion. -Peff
