Paul Mackerras [off-list ref] writes:
Another thing: I have noticed that git rev-parse --revs-only doesn't
pass the --merge and --left-right flags through, even though the help
for git rev-parse says that --revs-only means "Do not output flags and
parameters not meant for git-rev-list" (which I assume means the same
as "Only output flags and parameters meant for git rev-list"), and git
rev-list accepts and uses the --merge and --left-right flags. I
assume this is just an oversight in git rev-parse.
Yeah, the option list is not maintained well for the last few
years and needs to be updated.