# go: github.com/foo/bar@v1.4.0: unknown revision v1.4.0

- **ID:** `go/unknown-revision`
- **Domain:** go
- **Category:** module_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The requested tag/branch/commit does not exist in the remote repo (or was deleted). Often caused by typo or by relying on a branch that was renamed.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.16+ | active | — | — |
| 1.21+ | active | — | — |

## Workarounds

1. **** (95% success)
   ```
   git ls-remote --tags https://github.com/foo/bar
go get github.com/foo/bar@v1.3.9
   ```
2. **** (85% success)
   ```
   go get github.com/foo/bar@<sha>
# go.mod records v0.0.0-<date>-<sha>
   ```
3. **** (90% success)
   ```
   go get github.com/foo/bar@latest
   ```

## Dead Ends

- **** — the revision still does not exist upstream (90% fail)
- **** — cache is not the problem; the tag is missing (95% fail)
- **** — fails with 'replacement directory does not exist' (90% fail)