Merge pull request #66 from slimreaper35/build-args

build: Use normalized platform spec for ARG expansion

Author: chmeliik

integration_tests/build_test.go

@@ -713,13 +713,6 @@ LABEL test.label="platform-build-args-test"
 			imageLabel := imageLabels[label]
 			containerfileLabel := containerfileLabels[label]
 
-			// the *VARIANT values will be empty on platforms other than ARM
-			expectEmpty := strings.HasSuffix(label, "VARIANT") && runtime.GOARCH != "arm"
-			if !expectEmpty {
-				Expect(imageLabel).ToNot(BeEmpty(), fmt.Sprintf("label %s is empty on the built image", label))
-				Expect(containerfileLabel).ToNot(BeEmpty(), fmt.Sprintf("label %s is empty in the containerfile JSON", label))
-			}
-
 			Expect(imageLabel).To(Equal(containerfileLabel),
 				fmt.Sprintf("image label: %s=%s; containerfile label: %s=%s", label, imageLabel, label, containerfileLabel),
 			)

pkg/commands/build.go

@@ -556,7 +556,7 @@ func (c *Build) parseContainerfile() (*dockerfile.Dockerfile, error) {
 func (c *Build) createBuildArgExpander() (dockerfile.SingleWordExpander, error) {
 	// Define built-in ARG variables
 	// See https://docs.docker.com/build/building/variables/#multi-platform-build-arguments
-	platform := platforms.DefaultSpec()
+	platform := platforms.Normalize(platforms.DefaultSpec())
 	args := map[string]string{
 		// We current don't explicitly expose the --platform flag, so the TARGET* values always
 		// match the BUILD* values. If we add --platform handling, we would want to respect it here.