Rust: Because of wrong modified timestamp cargo rebuilds every time

[geropl]

Describe the bug
Between workspace restarts, the precision of the 'modified' timestamp on files under /workspace degrades from nanosecond to second precision.

As of now, cargo relies on this timestamp to detect dirty dependencies. The effect is that cargo rebuilds the whole project including all dependencies on each restart because it things the present artifacts are outdated.

To Reproduce

1. Create new workspace
2. touch test
3. stat test
4. Stop and restart workspace
5. stat test

Expected behavior
Workspace should have identical timestamps after restart.

[svenefftinge]

Oh, could that be the reason why cargo-watch is constantly rebuilding a project?
See https://spectrum.chat/gitpod/general/rust-rocket-web-server-port-not-served~cf954a11-8b39-4979-9ebb-5b02949ddf63

[geropl]

No, that sounds like something different. I'll try it, though.

Update: That seems to be indeed a special case, behaves the same locally for me: https://spectrum.chat/gitpod/general/rust-rocket-web-server-port-not-served~cf954a11-8b39-4979-9ebb-5b02949ddf63?m=MTU1NjUyNDEyMzEyNw==

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[geropl]

Oh, forgot about this one. Will verify and see if I can fix it.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[geropl]

Still the case, cmp. mtime here:

[axonasif]

Here's a workaround, use the following task structure in .gitpod.yml:

tasks:
  - name: Build and run
    init: |
      cargo build

      # workaround for https://github.com/gitpod-io/gitpod/issues/524
      find target -exec stat --format='%.Y %n' {} + > /workspace/.ts

    command: |
      # workaround for https://github.com/gitpod-io/gitpod/issues/524
      while read -r ts file; do touch -d "@${ts}" "${file}"; done < /workspace/.ts

      cargo run

[mustard-mh]

Modify time is not changed after workspace restart. As changes is inside component ws-daemon, fixing will land gitpod.io once next gen of workspace cluster deployed.

cc @kylos101 if we have any plan about next gen of workspace cluster

[kylos101]

👋 @mustard-mh , we probably won't replace workspace clusters for 2-3 more weeks, I think.