BuildKit skips unreferenced stages silently. The lint stage (added in PR [#152](sneak/upaas#152)) was never referenced by the builder stage via `COPY --from`, so it was being skipped entirely during `docker build .`. Linting was not actually running in CI.
This adds `COPY --from=lint /src/go.sum /dev/null` to the builder stage, creating a stage dependency that forces the lint stage to complete before the build proceeds.
Verified: `docker build .` now runs the lint stage (fmt-check + lint) and passes.
closes sneak/upaas#153
Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Reviewed-on: sneak/upaas#154
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
## Summary
Splits the Dockerfile into separate lint and build stages to provide faster CI feedback on formatting and lint issues.
### Changes
**Dockerfile:**
- **Lint stage** (`golangci/golangci-lint:v2.10.1`, pinned by sha256): Runs `make fmt-check` and `make lint` using the official golangci-lint image which has the linter pre-installed. No more downloading golangci-lint on every build.
- **Build stage** (`golang:1.25-alpine`, pinned by sha256): Runs `make test` and `make build`. Same alpine image as before.
- **Runtime stage**: Unchanged.
**Makefile:**
- Added `fmt-check` target for standalone gofmt checking.
- Refactored `check` target to use `fmt-check`, `lint`, `test` as dependencies instead of inline commands. Still works identically for local use.
### Benefits
- Lint failures surface immediately without waiting for golangci-lint download
- Uses official pre-built golangci-lint image instead of manual binary download
- Cleaner separation of concerns between lint and build stages
- `make check` still runs everything sequentially for local development
closes sneak/upaas#151
Co-authored-by: clawbot <clawbot@eeqj.de>
Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Reviewed-on: sneak/upaas#152
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
clawbotandclawbot
