It should be possible to explicitly add files outside of --subtree-only

[mikehearn]

Issue

I have a small-ish mono-repo (~2,100 files), so I'd like to use --subtree-only, but I also have some markdown files that contain internal documentation I'd like the model to read that are outside the usual subtree where the code is. Currently I can't write something like:

aider --subtree-only ../docs/*.md

because aider ignores the files outside the subtree.

Version and model info

v0.55.0 Main model: claude-3-5-sonnet-20240620 with diff edit format, infinite output Weak model: claude-3-haiku-20240307

[paul-gauthier]

You can use --read to add files from anywhere in the file system.

[mikehearn]

Thanks! If that's the right UX then it'd be good if aider spotted this mistake and notified the user about the --read flag.