gha: add linux/arm/v5 to list of platforms

[thaJeztah]

• relates to update to go1.22.6 moby/moby#46982

We include this in the moby/moby repo, but it looks like we didn't for the CLI.

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

[thaJeztah]

Heh. Looks like alpine doesn't support v5 anymore?

 > [build-alpine 1/1] RUN xx-apk add --no-cache musl-dev gcc:
0.064 fetch https://dl-cdn.alpinelinux.org/alpine/v3.20/main/armel/APKINDEX.tar.gz
0.237 fetch https://dl-cdn.alpinelinux.org/alpine/v3.20/community/armel/APKINDEX.tar.gz
0.237 WARNING: fetching https://dl-cdn.alpinelinux.org/alpine/v3.20/main: No such file or directory
0.264 WARNING: fetching https://dl-cdn.alpinelinux.org/alpine/v3.20/community: No such file or directory
0.265 ERROR: unable to select packages:
0.265   alpine-keys (no such package):
0.265     required by: world[alpine-keys]
------
Dockerfile:25
--------------------
  23 |     ARG TARGETPLATFORM
  24 |     # gcc is installed for libgcc only
  25 | >>> RUN xx-apk add --no-cache musl-dev gcc

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@@            Coverage Diff            @@
##             master    #5388   +/-   ##
=========================================
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[thaJeztah]

Interesting; this is causing failures on arm/v6 and arm/v7; it looks like we're explicitly disabling CGO (CGO_ENABLED=0), but then try to compile with -buildmode=pie - seems like something is off somewhere.

 > [build-plugins 1/1] RUN --mount=ro --mount=type=cache,target=/root/.cache     xx-go --wrap &&     TARGET=/out ./scripts/build/plugins e2e/cli-plugins/plugins/*:
0.127 Building static docker-helloworld
0.127 + CGO_ENABLED=0
0.127 + GO111MODULE=auto
0.127 + go build -o /out/plugins-linux-arm/docker-helloworld -tags ' osusergo' -ldflags ' -X "github.com/docker/cli/cli/version.GitCommit=5c123b1" -X "github.com/docker/cli/cli/version.BuildTime=2024-09-02T13:52:17Z" -X "github.com/docker/cli/cli/version.Version=pr-5387" -extldflags -static' -buildmode=pie github.com/docker/cli/cli-plugins/examples/helloworld
0.135 -buildmode=pie requires external (cgo) linking, but cgo is not enabled

The -buildmode=pie is probably set through GO_BUILDMODE ?

cli/scripts/build/plugins

Lines 8 to 19 in b0c41b7

	source ./scripts/build/.variables
	for p in cli-plugins/examples/* "$@" ; do
	[ -d "$p" ] || continue
	n=$(basename "$p")
	TARGET_PLUGIN="$(dirname "${TARGET}")/plugins-${GOOS}-${GOARCH}/docker-${n}"
	mkdir -p "$(dirname "${TARGET_PLUGIN}")"
	echo "Building $GO_LINKMODE $(basename "${TARGET_PLUGIN}")"
	(set -x ; CGO_ENABLED=0 GO111MODULE=auto go build -o "${TARGET_PLUGIN}" -tags "${GO_BUILDTAGS}" -ldflags "${GO_LDFLAGS}" ${GO_BUILDMODE} "github.com/docker/cli/${p}")
	done

[thaJeztah]

Right, so the .variables sets CGO_ENABLED=1 on arm;

cli/scripts/build/.variables

Lines 57 to 68 in b0c41b7

	if [ -z "$CGO_ENABLED" ]; then
	case "$(go env GOOS)" in
	linux)
	case "$(go env GOARCH)" in
	amd64|arm64|arm|s390x|riscv64)
	CGO_ENABLED=1
	;;
	*)
	CGO_ENABLED=0
	;;
	esac
	;;

And if enabled, it sets -buildmode=pie;

cli/scripts/build/.variables

Lines 79 to 88 in b0c41b7

	if [ "$CGO_ENABLED" = "1" ] && [ "$(go env GOOS)" != "windows" ]; then
	case "$(go env GOARCH)" in
	mips*|ppc64)
	# pie build mode is not supported on mips architectures
	;;
	*)
	GO_BUILDMODE="-buildmode=pie"
	;;
	esac
	fi

So that looks to be conflicting with the hard-coded CGO_ENABLED=0 in this script.

[thaJeztah]

Interestingly; doesn't fail on other PRs - wondering now what's causing that issue;

#18 [build-plugins 1/1] RUN --mount=ro --mount=type=cache,target=/root/.cache     xx-go --wrap &&     TARGET=/out ./scripts/build/plugins e2e/cli-plugins/plugins/*
#18 0.126 Building static docker-helloworld
#18 0.126 + CGO_ENABLED=0
#18 0.126 + GO111MODULE=auto
#18 0.126 + go build -o /out/plugins-linux-arm/docker-helloworld -tags ' osusergo' -ldflags ' -X "github.com/docker/cli/cli/version.GitCommit=0cebca4" -X "github.com/docker/cli/cli/version.BuildTime=2024-09-02T14:50:36Z" -X "github.com/docker/cli/cli/version.Version=pr-5389" -extldflags -static' -buildmode=pie github.com/docker/cli/cli-plugins/examples/helloworld
#18 19.75 # github.com/docker/cli/cli-plugins/examples/helloworld
#18 19.75 loadinternal: cannot find runtime/cgo
#18 19.85 Building static docker-badmeta
#18 19.85 + CGO_ENABLED=0
#18 19.85 + GO111MODULE=auto

[thaJeztah]

Heh, so this fixed the plugins being compiled, but looks like the binary itself does still require gcc, not just libgcc ?

 > [build 2/2] RUN --mount=type=bind,target=.,ro     --mount=type=cache,target=/root/.cache     --mount=type=tmpfs,target=cli/winresources     xx-go --wrap &&     TARGET=/out ./scripts/build/binary &&     xx-verify $([ "static" = "static" ] && echo "--static") /out/docker:
0.113 + go build -o /out/docker-linux-arm-v6 -tags ' osusergo pkcs11' -ldflags ' -X "github.com/docker/cli/cli/version.GitCommit=7e15277994" -X "github.com/docker/cli/cli/version.BuildTime=2024-09-02T14:39:44Z" -X "github.com/docker/cli/cli/version.Version=pr-5388" -extldflags -static' '-buildmode=pie' github.com/docker/cli/cmd/docker
29.74 # github.com/docker/cli/cmd/docker
29.74 /usr/local/go/pkg/tool/linux_amd64/link: running armv6-alpine-linux-musleabihf-clang failed: exit status 1
29.74 clang: warning: argument unused during compilation: '-pie' [-Wunused-command-line-argument]
29.74 ld.lld: error: cannot open crtbeginT.o: No such file or directory
29.74 ld.lld: error: unable to find library -lgcc
29.74 ld.lld: error: unable to find library -lgcc_eh
29.74 ld.lld: error: cannot open crtend.o: No such file or directory
29.74 clang: error: linker command failed with exit code 1 (use -v to see invocation)