`deno fmt --watch`, `deno lint --watch`, `deno test --watch` do not notice appearance of new files

[0x009922]

Version: Deno 2.2.3

deno 2.2.3 (stable, release, x86_64-unknown-linux-gnu)
v8 13.4.114.11-rusty
typescript 5.7.3

Steps to reproduce:

1. Create an empty directory, put empty foo.ts.
2. Run deno fmt --watch (or deno lint --watch)
3. Add bar.ts

Expected: watcher will pick up the newly created bar.ts.

Actual: nothing happens

[0x009922]

I would like to work on this issue, as I've noticed it while working on #14858 and they seem to be intersect.

Though, I am struggling to understand what would be the right way to choose paths to watch in this case. I guess that

• If paths are provided explicitly (e.g. deno fmt --watch ./foo.ts path/to/dir), then the watcher should watch for these paths only
• If not, then the watcher should watch for all paths falling into the include/exclude patterns. I am not sure what would be the "falling" criteria here, but here is where my thoughts currently are.

Would appreciate if you have any thoughts, thank you!

[0x009922]

Just found that deno test --watch also doesn't notice new files.

[stefnotch]

I also stumbled upon Deno's watch being re-implemented in multiple different places. Two more places that I noticed were

• the LSP is missing a watch mode

  deno/cli/lsp/testing/execution.rs

  Line 216 in 57dd66e

  pub async fn exec(

  , which I once tried to add WIP - feat(lsp): Run tests with file watcher #27762 (unfinished)
• deno bench has a watch mode

  deno/cli/tools/bench/mod.rs

  Line 492 in 57dd66e

  pub async fn run_benchmarks_with_watch(