Ignore patterns vs dangling symlinks

[tv42]

Emacs by default uses dangling symbolic links to guard against accidentally editing the same file from two editors: https://www.gnu.org/software/emacs/manual/html_node/emacs/Interlocking.html

In practice, this looks like

$ find -name '.#*' -ls
  6017389      4 lrwxrwxrwx   1 tv       tv             22 Aug 26 09:02 ./src/pages/test/.#foo.svelte -> [email protected]:1597784741

Since these symlinks have the same extension as the original file, they have a long history of triggering bugs in programs that either don't filter out hidden files, or just get very confused about seeing danling symlinks.

This causes routify to log errors like

[Routify] ✖ Failed to watch pages directory [Error: ENOENT: no such file or directory, stat 'src/pages/project/[project]/.#domains.svelte'] {
  errno: -2,
  code: 'ENOENT',
  syscall: 'stat',
  path: 'src/pages/project/[project]/.#domains.svelte'
}
(node:68) UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, stat '/src/src/pages/project/[project]/.#domains.svelte'

and it seems ignore patterns are not used for watching files:

$ cat routify.config.js 
module.exports = {
  routifyDir: "_routify",
  ignore: "**/.#*",
}

Things that could be improved:

1. ignore config is undocumented and assumes user just knows what's acceptable. The docs don't even say it's a glob pattern.

2. Watch functionality should obey ignore too.

3. lib/middleware/generateFileTree.js isAcceptedDir seems to already filter out leading underscores, it could filter out leading . too.

4. Based on a quick read, lib/middleware/generateFileTree.js applies the filter isIgnored too late; by the time isIgnored is used, the file has already been stat(2)'ed (isDirectory).

5. Same as above, it seems isIgnored doesn't apply to the else branch of if (isDir) at all.