refs: allow "HEAD" as decoration filter
The normalize_glob_ref() method was introduced in
65516f586b693 (log:
add option to choose which refs to decorate, 2017-11-21) to help with
decoration filters such as --decorate-refs=<filter> and
--decorate-refs-exclude=<filter>. The method has not been used anywhere
else.
At the moment, it is impossible to specify HEAD as a decoration filter
since normalize_glob_ref() prepends "refs/" to the filter if it isn't
already there.
Allow adding HEAD as a decoration filter by allowing the exact string
"HEAD" to not be prepended with "refs/". Add a test in t4202-log.sh that
would previously fail since the HEAD decoration would exist in the
output.
It is sufficient to only cover "HEAD" here and not include other special
refs like REBASE_HEAD. This is because HEAD is the only ref outside of
refs/* that is added to the list of decorations. However, we may want to
special-case these other refs in normalize_glob_ref() in the future.
Leave a NEEDSWORK comment for now.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>