should git rev-parse -q --verify on a range produce output?

[demerphq <demerphq@gmail.com>]

Hi all,

I was curious if it is a bug that `rev-parse -q --verify` produces
output for a commit range, and only reveals it is supposed to be used
with a single commit as an error message? When combined with -q it
make it seem like it has silently worked if you aren't careful to
check $? afterwards. (Which obviously some script wasn't or I wouldn't
be posting this. :-)

For example:

git rev-parse --verify -q HEAD^..HEAD; echo $?
869400a03fff1b3dcff82f3357d37ab506af2788
^13073008cfc15016d862c630d56323bb7c9d775e
1

"looks" like it has worked, producing two output refs, but as it shows
the exit code is 1. We have also seen it output a single line from a
range, when the entire range wasn't cloned.

It seems weird that it produces output at all in this case. Shouldn't
it see that it is a range and exit with a nonzero exit code
immediately? The docs say:

       --verify
           Verify that exactly one parameter is provided, and that it
can be turned into a raw 20-byte SHA-1 that
           can be used to access the object database. If so, emit it
to the standard output; otherwise, error out.
           ...
       -q, --quiet
           Only meaningful in --verify mode. Do not output an error
message if the first argument is not a valid
           object name; instead exit with non-zero status silently.
SHA-1s for valid object names are printed to
           stdout on success.

It seems to me that the second sentence from --verify indicates that
it should not produce output from a range at all, although I guess the
exact meaning of "error out" is ambiguous, and the last sentence of
the --quiet documentation is not incompatible with it also producing
output when it fails,  but it seems like if this is expected behavior
it should be documented more explicitly. Which makes me think it is a
bug. :-)

I am testing with git version 2.25.1 but this was encountered on
GitHub with whatever git they used as well. (We noticed this in a CI
pipeline using a shallow clone.)

cheers
Yves


-- 
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