# Lint phase, built alone by script/lint. The tools are invoked directly
# rather than through `make lint`, which runs docker itself and so cannot
# run inside a build step.
# golangci/golangci-lint:v2.14.0, 2026-10-07
FROM golangci/golangci-lint@sha256:ad862ba6b3798cbe0fd9fd7408d498fd74fbd2623a92406b2fd3898faf0bf98f AS lint
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .

# The gofmt half of `make fmt-check`. gofmt's output is assigned to a
# variable first so that its own exit status, as when it cannot parse a
# file, still fails the step.
RUN files="$(gofmt -s -l .)" && \
    if [ -n "$files" ]; then \
        echo "gofmt: files not formatted:" >&2; echo "$files" >&2; exit 1; \
    fi

# Validates .golangci.yml against the schema the pinned binary embeds.
RUN golangci-lint config verify --config .golangci.yml
RUN golangci-lint run --config .golangci.yml ./...

# Test phase, built alone by script/test. -race needs cgo and so a C
# compiler, which the Debian Go image ships and the alpine one does not.
#
# The tests run as nobody: several of them make a file unreadable and
# expect reading it to fail, and root reads it anyway. nobody has no home
# directory, so HOME is /tmp, where Go puts its build cache.
# golang:1.25-trixie, 2026-10-04
FROM golang@sha256:2c4c60ef415fbfa5e90300722293bef36c5e63fae17570ce18f580af933dbd73 AS test
USER nobody
ENV HOME=/tmp
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN go test -timeout 90s -race -cover ./... || \
    { echo "--- Rerunning with -v for details ---"; \
      go test -timeout 90s -race -v ./...; exit 1; }

# Build stage. Nothing is wanted from either phase above; the copies are
# what make BuildKit build them first, so this stage cannot run unless
# lint and test passed.
# golang:1.25-alpine, 2026-07-23
FROM golang@sha256:56961d79ea8129efddcc0b8643fd8a5416b4e6228cfd477e3fd61deb2672c587 AS builder
COPY --from=lint /src/go.sum /dev/null
COPY --from=test /src/go.sum /dev/null
RUN apk add --no-cache git make
# A tar-stream context keeps the sender's file owners, which git refuses.
RUN git config --system --add safe.directory /src
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .

# The version stamped into the binary: the VERSION build argument when
# one is given, otherwise `git describe --tags --always` of the .git in
# the build context. A context that carries .git and still yields no
# version fails the build; with neither, as from a source tarball, it is
# "dev". `make build` rather than `go build`, so the image and a host
# build share one compile recipe, cgo disabled included.
ARG VERSION
RUN version="${VERSION:-$(git describe --tags --always || echo dev)}"; \
    if [ -e .git ] && { [ -z "$version" ] || [ "$version" = dev ] || \
        [ "$version" = unknown ]; }; then \
        echo "no version could be derived although the build context carries .git" >&2; \
        exit 1; \
    fi; \
    make build VERSION="$version"

# Runtime stage, and the last one: a plain `docker build .` builds this
# stage's chain and nothing else.
# alpine:3.22, 2026-07-23
FROM alpine@sha256:14358309a308569c32bdc37e2e0e9694be33a9d99e68afb0f5ff33cc1f695dce

COPY --from=builder /src/sfdupes /usr/local/bin/sfdupes

ENTRYPOINT ["sfdupes"]