redundant dockerfile issue with build

src/spec-node/containerFeatures.ts

@@ -111,9 +111,8 @@ export async function extendImage(params: DockerResolverParameters, config: Subs
 	cliHost.mkdirp(emptyTempDir);
 	args.push(
 		'--target', featureBuildInfo.overrideTarget,
-		'-t', updatedImageName,
-		...additionalImageNames.map(name => ['-t', name]).flat(),
 		'-f', dockerfilePath,
+		...additionalImageNames.length > 0 ? additionalImageNames.map(name => ['-t', name]).flat() : ['-t', updatedImageName],
 		emptyTempDir
 	);
 
@@ -125,7 +124,7 @@ export async function extendImage(params: DockerResolverParameters, config: Subs
 		await dockerCLI(infoParams, ...args);
 	}
 	return {
-		updatedImageName: [ updatedImageName ],
+		updatedImageName: additionalImageNames.length > 0 ? additionalImageNames : [updatedImageName],
 		imageMetadata: getDevcontainerMetadata(imageBuildInfo.metadata, config, featuresConfig),
 		imageDetails: async () => imageBuildInfo.imageDetails,
 	};

src/test/cli.build.test.ts

@@ -27,6 +27,22 @@ describe('Dev Containers CLI', function () {
 
 	describe('Command build', () => {
 
+		it('should correctly configure the image name to push from --image-name with --push true', async () => {
+			const testFolder = `${__dirname}/configs/example`;
+			try {
+				const tags = await shellExec(`docker images --format "{{.Tag}}" demo`);
+				const imageTags = tags.stdout.trim().split('\n').filter(tag => tag !== '<none>');
+				if (imageTags.length > 1) {
+					console.log(`Image demo has more than one tag: ${imageTags.join(', ')}`);
+				} else {
+					await shellExec(`${cli} build --workspace-folder ${testFolder} --image-name demo:v1`);
+					assert.ok(false, 'should not succeed');
+				}
+			} catch (error) {
+				assert.equal(error.code, 'ERR_ASSERTION', 'Should fail with ERR_ASSERTION');
+			}
+		});
+
 		buildKitOptions.forEach(({ text, options }) => {
 			it(`should execute successfully with valid image config  [${text}]`, async () => {
 				const testFolder = `${__dirname}/configs/image`;