fix: require push=always for mergeTag, validate mutual exclusion with platformTag

- Fail early with a clear error if mergeTag is set without push: always,
  preventing silent no-ops when default push filtering skips the manifest.
- Fail early if both mergeTag and platformTag are set on the same step.
- Simplify redundant return logic in mergeTag runPost blocks.
- Add push: always to manifest job examples in docs.

Author: tgenov

azdo-task/DevcontainersCi/src/main.ts

@@ -26,7 +26,25 @@ export async function runMain(): Promise<void> {
 		task.setTaskVariable('hasRunMain', 'true');
 
 		const mergeTag = task.getInput('mergeTag');
+		const platformTag = task.getInput('platformTag');
+
+		if (mergeTag && platformTag) {
+			task.setResult(
+				task.TaskResult.Failed,
+				'mergeTag and platformTag cannot be used together - mergeTag is for the manifest merge job, platformTag is for per-platform build jobs',
+			);
+			return;
+		}
+
 		if (mergeTag) {
+			const pushOption = task.getInput('push');
+			if (pushOption !== 'always') {
+				task.setResult(
+					task.TaskResult.Failed,
+					"push must be set to 'always' when using mergeTag - the manifest merge job must push the resulting multi-arch image",
+				);
+				return;
+			}
 			console.log(
 				'mergeTag is set - skipping build (manifest merge will run in post step)',
 			);
@@ -58,7 +76,6 @@ export async function runMain(): Promise<void> {
 		const imageName = task.getInput('imageName');
 		const imageTag = task.getInput('imageTag');
 		const platform = task.getInput('platform');
-		const platformTag = task.getInput('platformTag');
 		const subFolder = task.getInput('subFolder') ?? '.';
 		const relativeConfigFile = task.getInput('configFile');
 		const runCommand = task.getInput('runCmd');
@@ -291,16 +308,13 @@ export async function runPost(): Promise<void> {
 	const imageTagArray = imageTag.split(/\s*,\s*/);
 
 	if (mergeTag) {
-		const success = await mergeMultiPlatformImages(
+		await mergeMultiPlatformImages(
 			imageName,
 			imageTagArray,
 			mergeTag,
 			createMultiPlatformImage,
 			(msg: string) => console.log(msg),
 		);
-		if (!success) {
-			return;
-		}
 		return;
 	}
 

docs/multi-platform-builds.md

@@ -128,6 +128,7 @@ jobs:
         with:
           imageName: ghcr.io/example/myimage
           mergeTag: linux-amd64,linux-arm64
+          push: always
 ```
 
 ### Azure DevOps Pipelines Example
@@ -169,4 +170,5 @@ stages:
       inputs:
         imageName: myregistry.azurecr.io/devcontainer
         mergeTag: linux-amd64,linux-arm64
+        push: always
 ```

github-action/dist/index.js

@@ -2166,7 +2166,17 @@ function runMain() {
             core.info('Starting...');
             core.saveState('hasRunMain', 'true');
             const mergeTag = emptyStringAsUndefined(core.getInput('mergeTag'));
+            const platformTag = emptyStringAsUndefined(core.getInput('platformTag'));
+            if (mergeTag && platformTag) {
+                core.setFailed('mergeTag and platformTag cannot be used together - mergeTag is for the manifest merge job, platformTag is for per-platform build jobs');
+                return;
+            }
             if (mergeTag) {
+                const pushOption = emptyStringAsUndefined(core.getInput('push'));
+                if (pushOption !== 'always') {
+                    core.setFailed("push must be set to 'always' when using mergeTag - the manifest merge job must push the resulting multi-arch image");
+                    return;
+                }
                 core.info('mergeTag is set - skipping build (manifest merge will run in post step)');
                 core.saveState('mergeTag', mergeTag);
                 return;
@@ -2189,7 +2199,6 @@ function runMain() {
             const imageName = emptyStringAsUndefined(core.getInput('imageName'));
             const imageTag = emptyStringAsUndefined(core.getInput('imageTag'));
             const platform = emptyStringAsUndefined(core.getInput('platform'));
-            const platformTag = emptyStringAsUndefined(core.getInput('platformTag'));
             const subFolder = core.getInput('subFolder');
             const relativeConfigFile = emptyStringAsUndefined(core.getInput('configFile'));
             const runCommand = core.getInput('runCmd');
@@ -2378,10 +2387,7 @@ function runPost() {
             return;
         }
         if (mergeTag) {
-            const success = yield (0, platform_1.mergeMultiPlatformImages)(imageName, imageTagArray, mergeTag, docker_1.createMultiPlatformImage, (msg) => core.info(msg));
-            if (!success) {
-                return;
-            }
+            yield (0, platform_1.mergeMultiPlatformImages)(imageName, imageTagArray, mergeTag, docker_1.createMultiPlatformImage, (msg) => core.info(msg));
             return;
         }
         const platform = emptyStringAsUndefined(core.getInput('platform'));

github-action/dist/index.js.map

@@ -36,7 +36,23 @@ export async function runMain(): Promise<void> {
 		core.saveState('hasRunMain', 'true');
 
 		const mergeTag = emptyStringAsUndefined(core.getInput('mergeTag'));
+		const platformTag = emptyStringAsUndefined(core.getInput('platformTag'));
+
+		if (mergeTag && platformTag) {
+			core.setFailed(
+				'mergeTag and platformTag cannot be used together - mergeTag is for the manifest merge job, platformTag is for per-platform build jobs',
+			);
+			return;
+		}
+
 		if (mergeTag) {
+			const pushOption = emptyStringAsUndefined(core.getInput('push'));
+			if (pushOption !== 'always') {
+				core.setFailed(
+					"push must be set to 'always' when using mergeTag - the manifest merge job must push the resulting multi-arch image",
+				);
+				return;
+			}
 			core.info(
 				'mergeTag is set - skipping build (manifest merge will run in post step)',
 			);
@@ -65,7 +81,6 @@ export async function runMain(): Promise<void> {
 		const imageName = emptyStringAsUndefined(core.getInput('imageName'));
 		const imageTag = emptyStringAsUndefined(core.getInput('imageTag'));
 		const platform = emptyStringAsUndefined(core.getInput('platform'));
-		const platformTag = emptyStringAsUndefined(core.getInput('platformTag'));
 		const subFolder: string = core.getInput('subFolder');
 		const relativeConfigFile = emptyStringAsUndefined(
 			core.getInput('configFile'),
@@ -293,16 +308,13 @@ export async function runPost(): Promise<void> {
 	}
 
 	if (mergeTag) {
-		const success = await mergeMultiPlatformImages(
+		await mergeMultiPlatformImages(
 			imageName,
 			imageTagArray,
 			mergeTag,
 			createMultiPlatformImage,
 			(msg: string) => core.info(msg),
 		);
-		if (!success) {
-			return;
-		}
 		return;
 	}