From 996875ae29a669ee3a50f9be387cd3d979ff739f Mon Sep 17 00:00:00 2001
From: clawbot <clawbot@noreply.git.eeqj.de>
Date: Sun, 15 Mar 2026 10:54:13 -0700
Subject: [PATCH] split Dockerfile into dedicated lint stage for faster CI

Use the golangci/golangci-lint image directly as a lint stage that runs
fmt-check and lint, rather than copying the binary into the builder stage.
BuildKit runs lint and test stages in parallel, so formatting and lint
failures surface much faster.

The COPY --from=lint dependency ensures BuildKit always executes the lint
stage (without it, unused stages are silently skipped).

Also add lint to the Makefile check target prereqs to match REPO_POLICIES
(check: test lint fmt-check).
---
 Dockerfile | 30 +++++++++++++++++++++++++-----
 Makefile   |  2 +-
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 9a816e2..e6dd403 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,16 +1,36 @@
+# Lint stage — fast feedback on formatting and lint issues
 # golangci/golangci-lint:v2.0.2 (2026-03-14)
-FROM golangci/golangci-lint@sha256:d55581f7797e7a0877a7c3aaa399b01bdc57d2874d6412601a046cc4062cb62e AS lint-bin
+FROM golangci/golangci-lint@sha256:d55581f7797e7a0877a7c3aaa399b01bdc57d2874d6412601a046cc4062cb62e AS lint
 
-# golang:1.23 (2026-03-14)
-FROM golang@sha256:60deed95d3888cc5e4d9ff8a10c54e5edc008c6ae3fba6187be6fb592e19e8c0 AS builder
-COPY --from=lint-bin /usr/bin/golangci-lint /usr/local/bin/golangci-lint
 WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
+
 COPY . .
+
 # Touch .pb.go so make does not try to regenerate via protoc (file is committed)
 RUN touch mfer/mf.pb.go
-RUN make check
+
+RUN make fmt-check
+RUN make lint
+
+# Build stage — tests and compilation
+# golang:1.23 (2026-03-14)
+FROM golang@sha256:60deed95d3888cc5e4d9ff8a10c54e5edc008c6ae3fba6187be6fb592e19e8c0 AS builder
+
+# Force BuildKit to run the lint stage by creating a stage dependency
+COPY --from=lint /src/go.sum /dev/null
+
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+# Touch .pb.go so make does not try to regenerate via protoc (file is committed)
+RUN touch mfer/mf.pb.go
+
+RUN make test
 RUN cd cmd/mfer && go build -tags urfave_cli_no_docs -o /mfer .
 
 FROM scratch
diff --git a/Makefile b/Makefile
index 89ad942..cab3f5b 100644
--- a/Makefile
+++ b/Makefile
@@ -32,7 +32,7 @@ $(PROTOC_GEN_GO):
 fixme:
 	@grep -nir fixme . | grep -v Makefile
 
-check: test fmt-check
+check: test lint fmt-check
 
 fmt-check: mfer/mf.pb.go
 	sh -c 'test -z "$$(gofmt -l .)"'