For inspiration, see also: Python's glob.escape function.
Their docs indicate only ?, *, and [ need to be escaped, but tests with VS Code globbing indicated that ] too needed escaping. In this PR, I am handling all four, and converting them to character range sequences.

Thanks for the contribution!

Trying this out, it might be a bit confusing to see extra square brackets in the "files to include" field when you want to search within them. Rather, would it be possible to change the way that the path gets interpreted the search actually happens? I believe that it happens around here:

That way, we don't see any difference in the UI.

Another thing: I tried it out and I'm still getting results from others folders? Unsure why.

@andreamah The screenshot you sent is indeed perplexing, though if it is a legit bug I don't think it's related to my changes -- perhaps the existing globbing functionality is broken on some platforms? Seems unlikely, but I can't think of another reason why it wouldn't be working on your side. Can you share which platform or OS you tried it on? Below are my results on Windows, and everything works as expected:

• Folder structure I am using for the test (I tried to mimic what you had based on the limited information from your comment):
  

• And here are results showing search works correctly with the escaped glob pattern that my change produced:
  

As you can see, only the results in subfolder[new] appear, as desired. I don't know why it behaved differently in your tests, and I would suggest it may be a separate bug on globbing, no on how this PR is escaping glob patterns. This PR looks correct as far as I can tell.

Re. your comment:

it might be a bit confusing to see extra square brackets in the "files to include" field when you want to search within them. Rather, would it be possible to change the way that the path gets interpreted the search actually happens?

I think what you're proposing is equivalent to saying "let's get rid of globbing as the mechanism to specify search paths in VS Code", which would be a very significant change, likely undesirable, and certainly out of scope for this PR. Globbing is a fine and commonplace choice for search tools, and it requires escaping special characters. I don't see any way around that... This PR simply implemsnts escaping properly, which was missing before.

Let me know how I can help further, I think this PR will improve the experience of VSCode users.