cells: Repro broken cell handling in file watcher

Summary: Explanation in the diff. This seems pretty bad, I'm not going to fix it though, because it's kind of hard.

Reviewed By: stepancheg

Differential Revision: D55573384

fbshipit-source-id: b7b4483fcf34179bdeb18e33713ab7ce9422e857

app/buck2_file_watcher/src/watchman/interface.rs

@@ -42,6 +42,9 @@ use crate::watchman::core::WatchmanEventType;
 use crate::watchman::core::WatchmanKind;
 
 struct WatchmanQueryProcessor {
+    // FIXME(JakobDegen): Storing these values statically is completely broken. See
+    // `tests/e2e/cells/test_file_watcher_resolution:test_changing_cell_location_bug` for a repro of
+    // a bug.
     cells: CellResolver,
     ignore_specs: HashMap<CellName, IgnoreSet>,
     retain_dep_files_on_watchman_fresh_instance: bool,