Is your feature request related to a problem? Please describe.

I use .gitignore to ignore everything in my home except for a few config paths. Combined with showUntrackedFiles, this reminds me of untracked new config files that I should add to the repo, and I can simply do yadm add . to stage all of them.

However, the files symlinked from alternatives / generated by templates via yadm alt often shows up as untracked as well, since they are often exempt by .gitignore as other regular files in the same directory. Obviously I do not want to commit those into the repo, hence I can't simply yadm add . anymore since it will add those generated files as well.

Describe the solution you'd like

I believe it is more natural to ignore the symlinked files by default when yadm add, or auto-generates a ignore list when yadm alt is run.

Describe alternatives you've considered

My solution to this is to add a pre_add hook, which ignores the generated files by adding it to a custom .altignore file:

#!/bin/bash
# pre_add: ignore symlinked alternative files

echo "### This file is auto-generated by \`$0\`" \
    > "$YADM_HOOK_WORK/.altignore"

git ls-files \
    | grep '##' \
    | sed 's/##.*$//g'\
    | sed 's|^\.config/yadm/alt/||' \
    | sort | uniq \
    >> "$YADM_HOOK_WORK/.altignore"

git config --local core.excludesfile "$YADM_HOOK_WORK/.altignore"

However, I believe this behavior should be default and can be built into yadm alt nicely.

P. S. I found that there is already an auto-exclude feature for encrypted files; we could simply adapt this to also exclude generated files.

https://github.com/TheLocehiliosan/yadm/blob/dd86c8a691deed7fb438b7ef07179040b0f05026/yadm#L1258-L1270