Managing a Nixpkgs fork without upstream tags

Enabling fetch.pruneTags causes my Nixpkgs Git checkout to constantly delete and fetch tags, since my fork is missing most tags that upstream has so they keep getting pruned when updating from origin and get re-created when fetching upstream.

One solution suggested for this was setting remotes.<name>.tagOpt = "--no-tags" but that didn’t do the job for me.

The thing that worked for me was to conditionally disable pruneTags for just the origin remote so it would not try to clear out the tags pulled from upstream. Achieved by running git config --local remotes.origin.pruneTags false.