It'd be potentially useful to have ! as a prefix added to our glob.ts utils. This could function similarly to how we already handle .gitignore files in the webworker search here:

1. if a file matches a normal line and doesn't match an !-line, exclude it (we do this today)
2. If it matches both a normal line and a !-line, include it
3. Otherwise, include it (we do this today)

This isn't quite as powerful as a real.gitignore as there are only two "layers" of include/exclude, whereas in gitignore each line introduces a new "layer", but I believe it would handle the 99% of cases well enough, for instance every example given to-date in #869.

To handle the many-layer case requires either:

• migrating to an array to configure files.exclude and search.exclude, which is undesirable from a backwards/forwards compatibility perspective
• taking care to ensure the existing *.exclude objects are handled in a key-order sensitive way, which is potentially undesirable from a JSON/JS object semantics compatibility perspective

cc @bpasero for any and all input on this