How can I tell whether the current working directory is ignored by Git?

Question

I have a git controlled directory (actually my home directory) within which there are ignored directories (e.g. trash space, and directories controlled by other VCSs). I want to be able to have my bash prompt show whether a directory is version controlled and if so by which VCS, but e.g. git rev-parse will always find the topmost .git directory.

Is there a way to ask git whether I'm in an untracked directory?

I've found this to work:

if ! git rev-parse 2>&/dev/null; then
    echo "not in git"
else
    PREFIX=$(git rev-parse --show-prefix)
    if [ -z "$PREFIX" ]; then
        echo "at git top level"
    elif [ -z $(cd $(git rev-parse --show-toplevel); \
          git ls-files -o --directory "${PREFIX%%/}")
        echo "tracked by git"
    else
        echo "untracked"
    fi
fi

However it seems very hackish and brittle. Is there a better way?

Answer 1

git clean -nd approach: If it is ignored directory, then git clean -d wants to remove it, so it is easy way to check status of current directory.

if git clean -xnd `pwd` | grep 'Would remove \./' > /dev/null; then
    echo "Inside ignored or untracked directory"
else
    echo "Inside normal directory"
fi

Tweak git clean to change rules about untracked files. Checked in my $HOME repository.

Note: don't experiment with git clean without -n lightly, it can clear things from your home.