Lack of commit history can cause failures when switching context from 'repo' to 'branch'

[electrofelix]

The current action defaults to recommending that callers ensure that the repo clone has it's full history with depth: 0 set as a option to the actions/checkout github action.

For large repos this can result in a noticeable slowdown as well as sometimes it can be easy for people to miss the requirement.

The action could add a small check when fetching tags to control whether to fetch commit history at the same time in order to allow for a more reliable check though maybe it would be better to add an option to allow users to explicitly opt in to doing this:

isShallow=$(git rev-parse --is-shallow-repository)
if [[ "${isShallow}" == "true" ]]; then
    git fetch --unshallow --filter=tree:0 --refetch origin --tags
else
    git fetch --tags
fi

This can be handy where people are using this action as part of another where they may not be controlling the initial clone. Instead of needing to make sure full history they can unshallow a clone to just get the commit history without downloading all the blobs. This also helps keep the action behaviour quick for larger repos.