vm: inotify: also trigger IN_CLOSE_WRITE when syncing file events

[florentigiraud-flare]

Fixes #1244. Related: #1341.

Problem

With --mount-inotify, Colima replays host file changes in the guest by running chmod with the file's current mode. Containers therefore only receive IN_ATTRIB. Watchers that ignore attribute-only events never react, for example Pants (pants --loop), which drops every metadata change except permissions (source), or air (#1341).

Change

The sync command now also opens the file for writing and closes it, without writing anything:

-sudo /bin/chmod <mode> <path>
+sudo /bin/sh -c '/bin/chmod "$1" "$2" && : >> "$2"' sh <mode> <path>

• chmod is kept, so watchers that rely on IN_ATTRIB behave exactly as before.
• : >> "$2" opens the file in append mode and closes it, which makes the kernel emit IN_OPEN + IN_CLOSE_WRITE. No byte is written.
• The mode and path are passed as positional arguments, not interpolated into the script, so paths with spaces or quotes are safe.

The command is built by a small syncEventCmd() helper so it can be unit tested.

Why it doesn't hit the editor problem from #1244

As we don't change the file on the host the editor shoud not be confuse with that.

Tests

• events_test.go: unit test of the generated command, including a path with spaces and quotes.
• events_linux_test.go (Linux only, runs in CI): runs the command on a temp file, then asserts that inotify reports IN_ATTRIB and IN_CLOSE_WRITE but not IN_MODIFY, and

The command is built by a small syncEventCmd() helper so it can be unit tested.

Manual end-to-end test (macOS 26.7 Apple Silicon, vz + virtiofs, docker runtime) on a real multi-container dev stack, editing files on the host:

• pants --loop test: now reruns tests (didn't react before);
• uvicorn/watchfiles, gunicorn --reload, Vite dev server, cargo watch: still reload as before.

LLM usage disclosure

This change was written with the help of an LLM (Claude): the investigation and the fix. The test was written manually with some guidance of claude because it's not a language I am confident enough to write something good but I reviewed every line and ran all the tests above myself.

[abiosoft]

Thanks :)

[florentigiraud-flare]

Thank you for the merge 🙏 🚀 just checking with you when do you think the release will be ?

[abiosoft]

Thank you for the merge 🙏 🚀 just checking with you when do you think the release will be ?

Hopefully within a week.