tsc should ignore hidden files by default (regression in 2.6)

[glasser]

TypeScript Version: 3.2.2

Search Terms: tsc watch hidden dot emacs

Code

glasser@glasser-mbp 0 /tmp $ mkdir tstest
glasser@glasser-mbp 0 /tmp $ cd tstest
glasser@glasser-mbp 0 /tmp/tstest $ echo '{"include": ["src/**/*.ts"]}' >tsconfig.json
glasser@glasser-mbp 0 /tmp/tstest $ mkdir src
glasser@glasser-mbp 0 /tmp/tstest $ touch src/foo.ts
glasser@glasser-mbp 0 /tmp/tstest $ npx -p typescript@3.2.2 tsc --build tsconfig.json --watch &
[1] 20017
glasser@glasser-mbp 0 /tmp/tstest $ npx: installed 1 in 1.452s
[12:52:03 PM] Starting compilation in watch mode...

[12:52:04 PM] Found 0 errors. Watching for file changes.


glasser@glasser-mbp 0 /tmp/tstest $ touch src/.foo.ts
glasser@glasser-mbp 0 /tmp/tstest $ �c[12:52:09 PM] File change detected. Starting incremental compilation...

[12:52:10 PM] Found 0 errors. Watching for file changes.


glasser@glasser-mbp 0 /tmp/tstest $ kill %1
[1]+  Terminated: 15          npx -p typescript@3.2.2 tsc --build tsconfig.json --watch
glasser@glasser-mbp 0 /tmp/tstest $ rm -rf src && mkdir src && touch src/foo.ts
glasser@glasser-mbp 0 /tmp/tstest $ npx -p typescript@2.6.1 tsc --project tsconfig.json --watch &
[1] 20062
glasser@glasser-mbp 0 /tmp/tstest $ npx: installed 1 in 1.646s
12:52:34 PM - Compilation complete. Watching for file changes.



glasser@glasser-mbp 0 /tmp/tstest $ touch src/.foo.ts
glasser@glasser-mbp 0 /tmp/tstest $ 12:52:41 PM - File change detected. Starting incremental compilation...



glasser@glasser-mbp 0 /tmp/tstest $ kill %1
[1]+  Terminated: 15          npx -p typescript@2.6.1 tsc --project tsconfig.json --watch
glasser@glasser-mbp 0 /tmp/tstest $ rm -rf src && mkdir src && touch src/foo.ts
glasser@glasser-mbp 0 /tmp/tstest $ npx -p typescript@2.5.3 tsc --project tsconfig.json --watch &
[1] 20107
glasser@glasser-mbp 0 /tmp/tstest $ npx: installed 1 in 1.35s
12:53:13 PM - Compilation complete. Watching for file changes.



glasser@glasser-mbp 0 /tmp/tstest $ touch src/bar.ts  # watching does work in general in this version
glasser@glasser-mbp 0 /tmp/tstest $ 12:53:26 PM - File change detected. Starting incremental compilation...


12:53:26 PM - Compilation complete. Watching for file changes.



glasser@glasser-mbp 0 /tmp/tstest $ touch src/.foo.ts

# no output happens --- 2.5.3 correctly ignores .foo.ts

Expected behavior:

Touching a file that starts with a dot should not trigger the watcher.

Actual behavior:

Touching a file that starts with a dot did not trigger the watcher in TS 2.0 through 2.5, but does trigger the watcher in 2.6 onward.

Related Issues:

This is the same issue filed by @evmar as #6861 in 2016. That issue was closed because it was fixed by #8484 in 2.0.2. However, it appears that the rewrite of the watcher in 2.6 (by @sheetalkamat I think) reintroduced the issue.

The impact of this issue is that emacs users with the default configuration will see tsc --watch refresh every time they start editing a file, because of emacs lock files. (As a workaround, Emacs users can stop using lock files with M-x customize-variable RET create-lockfiles.)

The original issue was considered to be important enough to fix in the first place, and I can't find anything showing that this change was intentional, so it seems like an unintended regression (though admittedly one that is over a year old).

[davazp]

I think this is more important than it seems. It affects vim and potentially many other editors. Probably there are not many complaints because tsc -w will clear the screen and it is not very noticeable unless you use preserveWatchOutput, but they would probably be happy with the "performance improvement" 🙂.

[michaelsbradleyjr]

I experience the effects of this regression when editing my projects with Emacs on macOS but not when editing VS Code. With Emacs, when you have unsaved changes in /some/path/foo.ts, a .#foo.ts lockfile is created as a sibling of foo.ts.

[sheetalkamat]

This should be fixed by #31954

[glasser]

Thanks @sheetalkamat and @suhasdeshpande !

[michaelsbradleyjr]

@glasser @sheetalkamat @suhasdeshpande I just found 13b7af6 in the commit history for the latest release (3.7.2) but I experienced this problem today in a project that has "typescript": "3.7.2" as a devDep.

[michaelsbradleyjr]

TypeScript/src/compiler/sys.ts

Line 333 in 13b7af6

export const ignoredPaths = ["/node_modules/.", "/.git", "/.#"];

Is "/.#" possibly too restrictive, only ignoring .# files if they're in the root of the project? In my case, they could be found at any depth w/in src/ relative to the root of the project.

[sheetalkamat]

They are handled at any depth since this is the check on absolute path to see of that pattern exists meaning file name starting with .#
I would recommend checking if that project is really using typescript 3.7.2 or not. If yes, then open a new issue with tsserver logs please.

[michaelsbradleyjr]

@sheetalkamat It is 100% definitely using typescript 3.7.2:

$ npx tsc --version
Version 3.7.2

I'm not sure about tsserver logs (please advise 🙏 ) but with:

$ npx tsc -b ./.tsconfig.collective.json --watch --preserveWatchOutput --verbose --extendedDiagnostic

(Note: the use of --preserveWatchOutput)

I got this when I started typing in Emacs within:

/some/path/some-package/src/index.ts

DirectoryWatcher:: Triggered with /some/path/some-package/src/.#index.ts :: WatchInfo: /some/path/some-package/src 1 Wild card directory /some/path/some-package/tsconfig.json
Elapsed:: 0ms DirectoryWatcher:: Triggered with /some/path/some-package/src/.#index.ts :: WatchInfo: /some/path/some-package/src 1 Wild card directory /some/path/some-package/tsconfig.json
[5:15:33 PM] File change detected. Starting incremental compilation...

I am confident at this point that #29461 should be re-opened rather than a new issue being created.