Re: [PATCH] rev-list: add option for --pretty without header

> Christian Couder <christian.couder@gmail.com> writes:
> 
> > On Wed, Jul 7, 2021 at 12:47 AM brian m. carlson
> > <sandals@crustytoothpaste.net> wrote:
> >>
> >> In general, we encourage users to use plumbing commands, like git
> >> rev-list, over porcelain commands, like git log, when scripting.
> >> However, git rev-list has one glaring problem that prevents it from
> >> being used in certain cases: when --pretty is used, it always prints out
> >> a line containing "commit" and the object ID.
> >
> > You say always, but it looks like it doesn't do it when
> > --pretty=oneline is used.
> 
> I've understood that he meant "when --pretty=format is used",
> though, as it is the only format whose intent was to allow
> generation of output stream that does not have to be preprocessed
> with "grep -v '^[0-9a-f]{40}'" etc.

> > It looks like the tests only check what happens in case
> > --pretty=format:'...' is used, but I wonder what the code does if a
> > builtin format is used.
> 
> Good point.

> I also think the handling of --abbrev-commit may need to be
> rethought with this change.  See here:
> 
>     diff --git a/builtin/rev-list.c b/builtin/rev-list.c
>     index 7677b1af5a..f571cc9598 100644
>     --- a/builtin/rev-list.c
>     +++ b/builtin/rev-list.c
>     @@ -132,7 +132,7 @@ static void show_commit(struct commit *commit, void *data)
>             if (revs->abbrev_commit && revs->abbrev)
>                     fputs(find_unique_abbrev(&commit->object.oid, revs->abbrev),
>                           stdout);
>     -	else
>     +	else if (revs->include_header)
>                     fputs(oid_to_hex(&commit->object.oid), stdout);
>             if (revs->print_parents) {
>                     struct commit_list *parents = commit->parents;
> 
> The original says that if --abbrev-commit is set and --abbrev is set
> to non-zero, we'd show unique abbreviation and if not, specifically,
> even when --abbrev-commit is set but --abbrev is set to 0, we didn't
> do the find_unique_abbrev() of full hexdigits but left the output to
> the else clause.  This was because the original code KNOWS that the
> else clause unconditionally emits the full commit object name.
> 
> That assumption, which made the original code's handling of
> "--abbrev-commit --abbrev=0" correct, no longer holds with the
> updated code.  What happens is with --no-commit-header, if we give
> "--abbrev-commit --abbrev=4", we still see the unique abbreviation
> that is not shorter than 4 hexdigits (i.e. "--no-commit-header" is
> ignored), but if we say "--abbrev-commit --abbrev=0", we do not see
> any commit header.
> 
> My hunch is that this "if / else", which determines if the commit
> header should give shortened or full length, should be skipped when
> the .include_header is false.