The default behaviour (i.e. `core.fsmonitor = "watchman"`) is to only use the file watcher as an optimisation — rather than scanning the entire folder every time JJ wants to make a snapshot, the watch keeps a list of which files have changed, and then when creating a snapshot, JJ only needs to check those files.
However, you can also add `core.watchman.register_snapshot_trigger = true` to the configuration, and this will make it so that every time the watcher sees that a file has changed, it automatically makes the new snapshot.
That said, neither of these are active by default, and neither are necessary by default. But if you're the sort of person who uses VS Code's "Timeline" view to see exactly how each file you've worked with has changed over time, then you might also appreciate the automatic snapshotting feature.
The default behaviour (i.e. `core.fsmonitor = "watchman"`) is to only use the file watcher as an optimisation — rather than scanning the entire folder every time JJ wants to make a snapshot, the watch keeps a list of which files have changed, and then when creating a snapshot, JJ only needs to check those files.
However, you can also add `core.watchman.register_snapshot_trigger = true` to the configuration, and this will make it so that every time the watcher sees that a file has changed, it automatically makes the new snapshot.
That said, neither of these are active by default, and neither are necessary by default. But if you're the sort of person who uses VS Code's "Timeline" view to see exactly how each file you've worked with has changed over time, then you might also appreciate the automatic snapshotting feature.