Post results for pull request events under PR head

Author: jwgmeligmeyling

README.md

@@ -48,7 +48,7 @@ jobs:
           ${{ runner.os }}-maven-
     - name: Build with Maven
       run: mvn -B verify checkstyle:checkstyle
-    - uses: jwgmeligmeyling/checkstyle-github-action@v1
+    - uses: jwgmeligmeyling/checkstyle-github-action@master
       with:
         path: '**/checkstyle-result.xml'
 ```
@@ -70,13 +70,29 @@ And do not forget to enable XML output for the Maven plugin:
 </build>
 ```
 
+Please make sure that by default workflows on `pull_request` events checkout [`refs/pull/:prNumber/merge`](https://help.github.com/en/actions/reference/events-that-trigger-workflows) instead of the head of the pull request.
+Due to this, line numbers for the generated violations may not align with the actual line numbers to which they are displayed on the `HEAD`.
+As it is, there is not really a sensible way to run this action on the merge commit of the pull request, because the result would be posted to an unnamed workflow for an otherwise invisible commit.
+Even for `pull_request` events there is the possibility to checkout the pull request head instead. In order to do so, change your `checkout` action accordingly:
+
+```yaml
+- uses: actions/checkout@v2
+  with:
+    ref: ${{ github.event.pull_request.head.sha }}
+```
+
 ## Other relevant actions
 This is a Github Action in a series of other GitHub Actions. Similar actions include:
 
 * [checkstyle-github-action](https://github.com/jwgmeligmeyling/checkstyle-github-action)
 * [pmd-github-action](https://github.com/jwgmeligmeyling/pmd-github-action)
 * [spotbugs-github-action](https://github.com/jwgmeligmeyling/spotbugs-github-action)
 
+## Known limitations
+Due to GitHub API limitations, we cannot specify to which Workflow Run (or underlying Check Suite) a newly created Check Run should be associated.
+As a result, workflows that trigger on several types of events, might push results under another event than the action was run in.
+For more information, see: https://github.com/jwgmeligmeyling/checkstyle-github-action/issues/2
+
 ## Contributing
 
 Install the dependencies  

dist/index.js

@@ -8476,11 +8476,15 @@ function createCheck(name, title, annotations, numErrors, conclusion) {
     return __awaiter(this, void 0, void 0, function* () {
         core.info(`Uploading ${annotations.length} / ${numErrors} annotations to GitHub as ${name} with conclusion ${conclusion}`);
         const octokit = github_2.getOctokit(core.getInput(constants_1.Inputs.Token));
-        const req = Object.assign(Object.assign({}, github_2.context.repo), { ref: github_2.context.sha });
+        let sha = github_2.context.sha;
+        if (github_2.context.payload.pull_request) {
+            sha = github_2.context.payload.pull_request.head.sha;
+        }
+        const req = Object.assign(Object.assign({}, github_2.context.repo), { ref: sha });
         const res = yield octokit.checks.listForRef(req);
         const existingCheckRun = res.data.check_runs.find(check => check.name === name);
         if (!existingCheckRun) {
-            const createRequest = Object.assign(Object.assign({}, github_2.context.repo), { head_sha: github_2.context.sha, conclusion,
+            const createRequest = Object.assign(Object.assign({}, github_2.context.repo), { head_sha: sha, conclusion,
                 name, status: 'completed', output: {
                     title,
                     summary: `${numErrors} violation(s) found`,

src/main.ts

@@ -95,9 +95,15 @@ async function createCheck(
     `Uploading ${annotations.length} / ${numErrors} annotations to GitHub as ${name} with conclusion ${conclusion}`
   )
   const octokit = getOctokit(core.getInput(Inputs.Token))
+  let sha = context.sha
+
+  if (context.payload.pull_request) {
+    sha = context.payload.pull_request.head.sha
+  }
+
   const req = {
     ...context.repo,
-    ref: context.sha
+    ref: sha
   }
 
   const res = await octokit.checks.listForRef(req)
@@ -108,7 +114,7 @@ async function createCheck(
   if (!existingCheckRun) {
     const createRequest = {
       ...context.repo,
-      head_sha: context.sha,
+      head_sha: sha,
       conclusion,
       name,
       status: <const>'completed',