Some commits are listed in outgoing even though they are already upstream.

Steps to reproduce

Run test-orphan_tag.sh. It:

• creates a bare git repository
• clones it into a regular folder in order to interact with it
• pushes some commits on the master branch
• creates a branch, pushes a commit on the branch and tags it with a tag message (the issue is not reproduced if there is no tag message)
• pushes everything to the bare repository
• deletes the branch, leaving the tag detached
• clones the bare git repository using hg-git
• runs hg outgoing in the Mercurial clone

Expected result

hg outgoing should report "no changes found".

Actual result

hg outgoing displays the tagged commit, even though that commit comes from the original git repository.

Software versions

• Mercurial 5.7.1
• hg-git 7d358a8736c4