[do not merge] test image-spec with embedded Platform

[thaJeztah]

• follow-up to Update uses of Image platform fields in OCI image-spec #44125
• testing "embed_platform" branch from Embed Platform in Image opencontainers/image-spec#949
• testing [do not merge] test image-spec with embedded Platform buildkit#3102

[thaJeztah]

Okay; BuildKit needs an update;

vendor/github.com/moby/buildkit/frontend/dockerfile/dockerfile2llb/image.go:70:4: unknown field 'Architecture' in struct literal of type v1.Image
vendor/github.com/moby/buildkit/frontend/dockerfile/dockerfile2llb/image.go:71:4: unknown field 'OS' in struct literal of type v1.Image

[thaJeztah]

=== CONT  TestIntegration/TestEmptyDestDir/worker=dockerd/fileop=false/frontend=builtin
    dockerfile_test.go:405: 
        	Error Trace:	dockerfile_test.go:405
        	            				run.go:88
        	            				run.go:202
        	Error:      	Received unexpected error:
        	            	support for "build-arg:BUILDKIT_DISABLE_FILEOP" was removed in BuildKit 0.11
        	            	github.com/moby/buildkit/util/stack.Enable
        	            		/src/util/stack/stack.go:77
        	            	github.com/moby/buildkit/util/grpcerrors.FromGRPC
        	            		/src/util/grpcerrors/grpcerrors.go:188
        	            	github.com/moby/buildkit/util/grpcerrors.UnaryClientInterceptor
        	            		/src/util/grpcerrors/intercept.go:41
        	            	google.golang.org/grpc.(*ClientConn).Invoke
        	            		/src/vendor/google.golang.org/grpc/call.go:35
        	            	github.com/moby/buildkit/api/services/control.(*controlClient).Solve
        	            		/src/api/services/control/control.pb.go:1443
        	            	github.com/moby/buildkit/client.(*Client).solve.func2
        	            		/src/client/solve.go:208
        	            	golang.org/x/sync/errgroup.(*Group).Go.func1
        	            		/src/vendor/golang.org/x/sync/errgroup/errgroup.go:57
        	            	runtime.goexit
        	            		/usr/local/go/src/runtime/asm_amd64.s:1581
        	            	failed to solve
        	            	github.com/moby/buildkit/client.(*Client).solve.func2
        	            		/src/client/solve.go:221
        	            	golang.org/x/sync/errgroup.(*Group).Go.func1
        	            		/src/vendor/golang.org/x/sync/errgroup/errgroup.go:57
        	            	runtime.goexit
        	            		/usr/local/go/src/runtime/asm_amd64.s:1581
        	Test:       	TestIntegration/TestEmptyDestDir/worker=dockerd/fileop=false/frontend=builtin
    sandbox.go:235: stderr: /usr/bin/dockerd

[thaJeztah]

I guess the above #44124 (comment) will be fixed if I update GHA to use a newer version of the integration tests;

moby/.github/workflows/buildkit.yml

Lines 73 to 75 in 924edb9

	# FIXME(thaJeztah) temporarily overriding version to use for tests; see https://github.com/moby/moby/pull/44028#issuecomment-1225964929
	# echo "BUILDKIT_REF=$(./hack/buildkit-ref)" >> $GITHUB_ENV
	echo "BUILDKIT_REF=8e2d9b9006caadb74c1745608889a37ba139acc1" >> $GITHUB_ENV

I'm wondering though; is that option set in the client, and do existing clients set that option? Would that mean that (say) docker cli 20.10 or an older version of Buildx would not be compatible with newer versions of BuildKit daemons / builders?

/cc @crazy-max