Rust: Because of wrong modified timestamp cargo rebuilds every time
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Description
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cargo rebuilds the whole project including all dependencies on each restart because it things the present artifacts are outdated.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
- Create new workspace
touch teststat test- Stop and restart workspace
stat test
Expected behavior
Workspace should have identical timestamps after restart.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the timestamp change in a workspace using the listed touch and stat steps, comparing the file before and after a restart. Read the linked Cargo fingerprint logic to understand how modified timestamps affect dependency freshness. Done means files under /workspace retain identical timestamp precision across restarts and cargo no longer rebuilds the project unnecessarily.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- infrastructure
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100