Remove aliases created by buildx when installing by default

If the action is configured to install buildx by default using the
input then docker buildx sets up docker build as an alias for buildx
making all docker build calls use the buildx builder instead of
traditional builders. The action didn't perform cleanup in this case to
uninstall the aliases which meant that any future workflows running on
same GitHub Actions runner would get the buildx builders even if it did
not explicitly request it.

This commit tracks if the aliases were installed and removes them during
post step of the action if so.

Signed-off-by: Ashhar Hasan <hashhar_dev@outlook.com>

src/main.ts

@@ -178,6 +178,7 @@ actionsToolkit.run(
         throw new Error(`Cannot set buildx as default builder without the Docker CLI`);
       }
       await core.group(`Setting buildx as default builder`, async () => {
+        stateHelper.setBuildxIsDefaultBuilder(true);
         const installCmd = await toolkit.buildx.getCommand(['install']);
         await Exec.getExecOutput(installCmd.command, installCmd.args, {
           ignoreReturnCode: true
@@ -278,5 +279,17 @@ actionsToolkit.run(
         fs.rmSync(stateHelper.certsDir, {recursive: true});
       });
     }
+
+    if (stateHelper.buildxIsDefaultBuilder) {
+      await core.group(`Restoring default builder`, async () => {
+        await Exec.getExecOutput('docker', ['buildx', 'uninstall'], {
+          ignoreReturnCode: true
+        }).then(res => {
+          if (res.stderr.length > 0 && res.exitCode != 0) {
+            core.warning(`${res.stderr.match(/(.*)\s*$/)?.[0]?.trim() ?? 'unknown error'}`);
+          }
+        });
+      });
+    }
   }
 );

src/state-helper.ts

@@ -8,6 +8,7 @@ export const containerName = process.env['STATE_containerName'] || '';
 export const certsDir = process.env['STATE_certsDir'] || '';
 export const tmpDockerContext = process.env['STATE_tmpDockerContext'] || '';
 export const cleanup = /true/i.test(process.env['STATE_cleanup'] || '');
+export const buildxIsDefaultBuilder = /true/i.test(process.env['STATE_buildxIsDefaultBuilder'] || '');
 
 export function setDebug(debug: string) {
   core.saveState('isDebug', debug);
@@ -40,3 +41,7 @@ export function setTmpDockerContext(tmpDockerContext: string) {
 export function setCleanup(cleanup: boolean) {
   core.saveState('cleanup', cleanup);
 }
+
+export function setBuildxIsDefaultBuilder(buildxIsDefaultBuilder: boolean) {
+  core.saveState('buildxIsDefaultBuilder', buildxIsDefaultBuilder);
+}