feat(core): add wrappers functions to manage problem matchers

packages/core/README.md

@@ -263,6 +263,29 @@ var pid = core.getState("pidToKill");
 process.kill(pid);
 ```
 
+#### Problem matchers
+
+You can use this library to register problem matchers for your action.
+Problem matchers are used to scan the output of actions for a specified regex pattern and surface that information prominently in the UI.
+
+#### Register a problem matcher
+
+```js
+const core = require('@actions/core');
+
+// Add matcher file "my-matcher.json"
+core.addMatcher('my-matcher.json');
+```
+
+#### Remove a problem matcher
+
+```js
+const core = require('@actions/core');
+
+// Remove the problem matcher with the owner "my-matcher-owner"
+core.removeMatcher('my-matcher-owner');
+```
+
 #### OIDC Token
 
 You can use these methods to interact with the GitHub OIDC provider and get a JWT ID token which would help to get access token from third party cloud providers.

packages/core/__tests__/core.test.ts

@@ -634,6 +634,16 @@ describe('@actions/core', () => {
     core.setCommandEcho(false)
     assertWriteCalls([`::echo::off${os.EOL}`])
   })
+
+  it('addMatcher adds a problem matcher', () => {
+    core.addMatcher('my-matcher.json')
+    assertWriteCalls([`::add-matcher::my-matcher.json${os.EOL}`])
+  })
+
+  it('removeMatcher removes a problem matcher', () => {
+    core.removeMatcher('my-matcher-owner')
+    assertWriteCalls([`::remove-matcher owner=my-matcher-owner::${os.EOL}`])
+  })
 })
 
 // Assert that process.stdout.write calls called only with the given arguments.

packages/core/src/core.ts

@@ -364,9 +364,27 @@ export async function group<T>(name: string, fn: () => Promise<T>): Promise<T> {
 }
 
 //-----------------------------------------------------------------------
-// Wrapper action state
+// Problem Matchers Commands
 //-----------------------------------------------------------------------
 
+/**
+ * Adds a matcher to the process
+ *
+ * @param path   path to the matcher json file
+ */
+export function addMatcher(path: string): void {
+  issueCommand('add-matcher', {}, path)
+}
+
+/**
+ * Removes a matcher from the process
+ *
+ * @param owner   owner of the matcher
+ */
+export function removeMatcher(owner: string): void {
+  issueCommand('remove-matcher', {owner}, null)
+}
+
 /**
  * Saves state for current action, the state can only be retrieved by this action's post job execution.
  *
@@ -393,6 +411,10 @@ export function getState(name: string): string {
   return process.env[`STATE_${name}`] || ''
 }
 
+//-----------------------------------------------------------------------
+// Wrapper action state
+//-----------------------------------------------------------------------
+
 export async function getIDToken(aud?: string): Promise<string> {
   return await OidcClient.getIDToken(aud)
 }