Added output

README.md

@@ -109,12 +109,12 @@ jobs:
 
 Various inputs are defined in [`action.yml`](action.yml) to let you configure the labeler:
 
-| Name | Description | Default |
-| - | - | - |
-| `repo-token` | Token to use to authorize label changes. Typically the `GITHUB_TOKEN` secret, with `contents:read` and `pull-requests:write` access | `github.token` |
-| `configuration-path` | The path to the label configuration file | `.github/labeler.yml` |
-| `sync-labels` | Whether or not to remove labels when matching files are reverted or no longer changed by the PR | `false` |
-| `dot` | Whether or not to auto-include paths starting with dot (e.g. `.github`) | `false` |
+| Name                 | Description                                                                                     | Default               |
+|----------------------|-------------------------------------------------------------------------------------------------|-----------------------|
+| `repo-token`         | Token to use to authorize label changes. Typically the GITHUB_TOKEN secret                      | N/A                   |
+| `configuration-path` | The path to the label configuration file                                                        | `.github/labeler.yml` |
+| `sync-labels`        | Whether or not to remove labels when matching files are reverted or no longer changed by the PR | `false`               |
+| `dot`                | Whether or not to auto-include paths starting with dot (e.g. `.github`)                         | `false`               |
 
 When `dot` is disabled and you want to include _all_ files in a folder:
 
@@ -131,6 +131,44 @@ label1:
 - path/to/folder/**
 ```
 
+#### Outputs 
+
+Labeler provides the following outputs:  
+
+| Name         | Description                                               |
+|--------------|-----------------------------------------------------------|
+| `new-labels` | A comma-separated list of all new labels                  |
+| `all-labels` | A comma-separated list of all labels that the PR contains |
+
+The following example performs steps based on the output of labeler:
+```yml
+name: "My workflow"
+on:
+- pull_request_target
+
+jobs:
+  triage:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+    - id: label-the-PR
+      uses: actions/labeler@v3
+
+    - id: run-frontend-tests
+      if: contains(fromJson(steps.label-the-PR.outputs.all-labels), 'frontend')
+      run: |
+        echo "Running frontend tests..."
+        # Put your commands for running frontend tests here
+
+    - id: run-backend-tests
+      if: contains(fromJson(steps.label-the-PR.outputs.all-labels), 'backend')
+      run: |
+        echo "Running backend tests..."
+        # Put your commands for running backend tests here
+```
+
 ## Permissions
 
 In order to add labels to pull requests, the GitHub labeler action requires

__tests__/main.test.ts

@@ -13,6 +13,7 @@ const reposMock = jest.spyOn(gh.rest.repos, 'getContent');
 const paginateMock = jest.spyOn(gh, 'paginate');
 const getPullMock = jest.spyOn(gh.rest.pulls, 'get');
 const coreWarningMock = jest.spyOn(core, 'warning');
+const setOutputSpy = jest.spyOn(core, 'setOutput');
 
 const yamlFixtures = {
   'only_pdfs.yml': fs.readFileSync('__tests__/fixtures/only_pdfs.yml')
@@ -50,12 +51,21 @@ describe('run', () => {
     await run();
 
     expect(setLabelsMock).toHaveBeenCalledTimes(1);
+
     expect(setLabelsMock).toHaveBeenCalledWith({
       owner: 'monalisa',
       repo: 'helloworld',
       issue_number: 123,
       labels: ['touched-a-pdf-file']
     });
+    expect(setOutputSpy).toHaveBeenCalledWith(
+      'new-labels',
+      'touched-a-pdf-file'
+    );
+    expect(setOutputSpy).toHaveBeenCalledWith(
+      'all-labels',
+      'touched-a-pdf-file'
+    );
   });
 
   it('(with dot: true) adds labels to PRs that match our glob patterns', async () => {
@@ -77,6 +87,14 @@ describe('run', () => {
       issue_number: 123,
       labels: ['touched-a-pdf-file']
     });
+    expect(setOutputSpy).toHaveBeenCalledWith(
+      'new-labels',
+      'touched-a-pdf-file'
+    );
+    expect(setOutputSpy).toHaveBeenCalledWith(
+      'all-labels',
+      'touched-a-pdf-file'
+    );
   });
 
   it('(with dot: false) does not add labels to PRs that do not match our glob patterns', async () => {
@@ -92,6 +110,8 @@ describe('run', () => {
     await run();
 
     expect(setLabelsMock).toHaveBeenCalledTimes(0);
+    expect(setOutputSpy).toHaveBeenCalledWith('new-labels', '');
+    expect(setOutputSpy).toHaveBeenCalledWith('all-labels', '');
   });
 
   it('(with dot: true) does not add labels to PRs that do not match our glob patterns', async () => {
@@ -128,6 +148,8 @@ describe('run', () => {
       issue_number: 123,
       labels: ['manually-added']
     });
+    expect(setOutputSpy).toHaveBeenCalledWith('new-labels', '');
+    expect(setOutputSpy).toHaveBeenCalledWith('all-labels', 'manually-added');
   });
 
   it('(with sync-labels: false) it issues no delete calls even when there are preexisting PR labels that no longer match the glob pattern', async () => {
@@ -148,6 +170,11 @@ describe('run', () => {
     await run();
 
     expect(setLabelsMock).toHaveBeenCalledTimes(0);
+    expect(setOutputSpy).toHaveBeenCalledWith('new-labels', '');
+    expect(setOutputSpy).toHaveBeenCalledWith(
+      'all-labels',
+      'touched-a-pdf-file,manually-added'
+    );
   });
 
   it('(with sync-labels: false) it only logs the excess labels', async () => {
@@ -178,6 +205,9 @@ describe('run', () => {
       'Maximum of 100 labels allowed. Excess labels: touched-a-pdf-file',
       {title: 'Label limit for a PR exceeded'}
     );
+    const allLabels: string = existingLabels.map(i => i.name).join(',');
+    expect(setOutputSpy).toHaveBeenCalledWith('new-labels', '');
+    expect(setOutputSpy).toHaveBeenCalledWith('all-labels', allLabels);
   });
 });
 

action.yml

@@ -19,6 +19,11 @@ inputs:
     default: false
     required: false
 
+outputs:
+  new-labels:
+    description: 'A comma-separated list of all new labels'
+  all-labels:
+    description: 'A comma-separated list of all labels that the PR contains'
 runs:
   using: 'node16'
   main: 'dist/index.js'

dist/index.js

@@ -68,8 +68,8 @@ function run() {
             core.debug(`fetching changed files for pr #${prNumber}`);
             const changedFiles = yield getChangedFiles(client, prNumber);
             const labelGlobs = yield getLabelGlobs(client, configPath);
-            const prLabels = pullRequest.labels.map(label => label.name);
-            const allLabels = new Set(prLabels);
+            const preexistingLabels = pullRequest.labels.map(l => l.name);
+            const allLabels = new Set(preexistingLabels);
             for (const [label, globs] of labelGlobs.entries()) {
                 core.debug(`processing ${label}`);
                 if (checkGlobs(changedFiles, globs, dot)) {
@@ -79,12 +79,16 @@ function run() {
                     allLabels.delete(label);
                 }
             }
-            const labels = [...allLabels].slice(0, GITHUB_MAX_LABELS);
+            const labelsToAdd = [...allLabels].slice(0, GITHUB_MAX_LABELS);
             const excessLabels = [...allLabels].slice(GITHUB_MAX_LABELS);
             try {
-                if (!isListEqual(prLabels, labels)) {
-                    yield setLabels(client, prNumber, labels);
+                let newLabels = [];
+                if (!isListEqual(labelsToAdd, preexistingLabels)) {
+                    yield setLabels(client, prNumber, labelsToAdd);
+                    newLabels = labelsToAdd.filter(l => !preexistingLabels.includes(l));
                 }
+                core.setOutput('new-labels', newLabels.join(','));
+                core.setOutput('all-labels', labelsToAdd.join(','));
                 if (excessLabels.length) {
                     core.warning(`Maximum of ${GITHUB_MAX_LABELS} labels allowed. Excess labels: ${excessLabels.join(', ')}`, { title: 'Label limit for a PR exceeded' });
                 }

src/labeler.ts

@@ -43,8 +43,8 @@ export async function run() {
       configPath
     );
 
-    const prLabels: string[] = pullRequest.labels.map(label => label.name);
-    const allLabels: Set<string> = new Set(prLabels);
+    const preexistingLabels = pullRequest.labels.map(l => l.name);
+    const allLabels: Set<string> = new Set<string>(preexistingLabels);
 
     for (const [label, globs] of labelGlobs.entries()) {
       core.debug(`processing ${label}`);
@@ -55,14 +55,20 @@ export async function run() {
       }
     }
 
-    const labels = [...allLabels].slice(0, GITHUB_MAX_LABELS);
+    const labelsToAdd = [...allLabels].slice(0, GITHUB_MAX_LABELS);
     const excessLabels = [...allLabels].slice(GITHUB_MAX_LABELS);
 
     try {
-      if (!isListEqual(prLabels, labels)) {
-        await setLabels(client, prNumber, labels);
+      let newLabels: string[] = [];
+
+      if (!isListEqual(labelsToAdd, preexistingLabels)) {
+        await setLabels(client, prNumber, labelsToAdd);
+        newLabels = labelsToAdd.filter(l => !preexistingLabels.includes(l));
       }
 
+      core.setOutput('new-labels', newLabels.join(','));
+      core.setOutput('all-labels', labelsToAdd.join(','));
+
       if (excessLabels.length) {
         core.warning(
           `Maximum of ${GITHUB_MAX_LABELS} labels allowed. Excess labels: ${excessLabels.join(