illumos: track renames

[nshalman]

Follows from #628

Assigning to myself for now. If I don't make any progress on this in 2 weeks, we should attach the help wanted label and unassign it from me.

Breadcrumb for how to pick up on this :

I unexported RenamedFrom to renamedFrom for now, and the tests aren't run on platforms where this isn't supported yet (kq, fen). This way new features like this can be developed and merged in to main without holding up everything, and PRs can be a bit smaller in scope (I did some work on kqueue, which required rewriting significant bits of it).

To enable running the rename tests, add new platforms to supportsRename() in helpers_test.go over here: https://github.com/fsnotify/fsnotify/pull/628/files#diff-62f46d82044a129997b958c0f7eb6a95038395d337176418d3dffae98d9332d1R636

The goal would be to get the rename tests enabled on illumos and have them passing correctly. Additionally it would be nice, if possible, to remove any other illumos specific quirks in the test suite.

[arp242]

There's actually a few other illumos issues as well:

• inotify: implement WithNoFollow() #631: option to disable following links. I tried replacing the Stat() with Lstat(), but that didn't really seem to work. Tests enabled with supportsNofollow()

• Support filtering events, add unsupported events #629; mostly the filtering events. Tests enabled with supportsFilter().

• Add recursive watcher for Windows backend #540: Recursive watcher. Tests enabled with supportsRecurse().

But really, there's no hurries with any of this, many of these have been feature requests that have been around for years, some over a decade. People have died of old age waiting for this – literally. It can wait a few months more.

I suspect one reason these features have never been done in spite of popular demand is that it required implementing at least 3 (now 4) different systems all at once; it's a lot to keep in your head, and a lot of work to squeeze in.

Just let me know when/if you look at any of this, to prevent double work.