fs: improve errors thrown from fs.watch()

- Add an accessor property `initialized `to FSEventWrap to
  check the state of the handle from the JS land
- Introduce ERR_FS_WATCHER_ALREADY_STARTED so calling start()
  on a watcher that is already started will throw instead of
  doing nothing silently.
- Introduce ERR_FS_WATCHER_NOT_STARTED so calling close()
  on a watcher that is already closed will throw instead of
  doing nothing silently.
- Validate the filename passed to fs.watch()
- Assert that the handle in the watcher are instances of
  FSEvent instead of relying on the illegal invocation error
  from the VM.
- Add more assertions in FSEventWrap methods now that we check
  `initialized` and the filename in JS land before invoking
  the binding.
- Use uvException instead of errornoException to create
  the errors with the error numbers from libuv to make them
  consistent with other errors in fs.

TODO:

- Improve fs.watchFile() the same way this patch improves fs.watch()
- It seems possible to fire both rename and change event from libuv
  together now that we can check if the handle is closed via
  `initialized` in JS land.

PR-URL: https://github.com/nodejs/node/pull/19089
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

1 files changed, 5 insertions, 2 deletions

diff --git a/test/sequential/test-fs-watch.js b/test/sequential/test-fs-watch.js
index b672e9c753..91d750acd0 100644
--- a/test/sequential/test-fs-watch.js
+++ b/test/sequential/test-fs-watch.js
@@ -112,12 +112,15 @@ tmpdir.refresh();
 // https://github.com/joyent/node/issues/6690
 {
   let oldhandle;
-  assert.throws(function() {
+  assert.throws(() => {
     const w = fs.watch(__filename, common.mustNotCall());
     oldhandle = w._handle;
     w._handle = { close: w._handle.close };
     w.close();
-  }, /^TypeError: Illegal invocation$/);
+  }, {
+    message: 'handle must be a FSEvent',
+    code: 'ERR_ASSERTION'
+  });
   oldhandle.close(); // clean up
 
   assert.throws(function() {