feat: expose GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT

.github/workflows/build.yml

@@ -50,6 +50,7 @@ jobs:
           echo $GITHUB_BASE_REF_SLUG_URL
           echo $GITHUB_EVENT_REF_SLUG_URL
           echo $GITHUB_SHA_SHORT
+          echo $GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT
 
   test-win:
     runs-on: windows-latest
@@ -68,3 +69,4 @@ jobs:
           echo $env:GITHUB_BASE_REF_SLUG_URL
           echo $env:GITHUB_EVENT_REF_SLUG_URL
           echo $env:GITHUB_SHA_SHORT
+          echo $env:GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT

README.md

@@ -28,19 +28,20 @@ Others `Slug`-ish commands are available:
 - name: Print slug/short variables
   run: |
     echo "Slug variables"
-    echo "   ref        : ${{ env.GITHUB_REF_SLUG }}"
-    echo "   head ref   : ${{ env.GITHUB_HEAD_REF_SLUG }}"
-    echo "   base ref   : ${{ env.GITHUB_BASE_REF_SLUG }}"
-    echo "   event ref  : ${{ env.GITHUB_EVENT_REF_SLUG }}"
-    echo "   repository : ${{ env.GITHUB_REPOSITORY_SLUG }}"
+    echo "   ref                 : ${{ env.GITHUB_REF_SLUG }}"
+    echo "   head ref            : ${{ env.GITHUB_HEAD_REF_SLUG }}"
+    echo "   base ref            : ${{ env.GITHUB_BASE_REF_SLUG }}"
+    echo "   event ref           : ${{ env.GITHUB_EVENT_REF_SLUG }}"
+    echo "   repository          : ${{ env.GITHUB_REPOSITORY_SLUG }}"
     echo "Slug URL variables"
-    echo "   ref        : ${{ env.GITHUB_REF_SLUG_URL }}"
-    echo "   head ref   : ${{ env.GITHUB_HEAD_REF_SLUG_URL }}"
-    echo "   base ref   : ${{ env.GITHUB_BASE_REF_SLUG_URL }}"
-    echo "   event ref  : ${{ env.GITHUB_EVENT_REF_SLUG_URL }}"
-    echo "   repository : ${{ env.GITHUB_REPOSITORY_SLUG_URL }}"
+    echo "   ref                 : ${{ env.GITHUB_REF_SLUG_URL }}"
+    echo "   head ref            : ${{ env.GITHUB_HEAD_REF_SLUG_URL }}"
+    echo "   base ref            : ${{ env.GITHUB_BASE_REF_SLUG_URL }}"
+    echo "   event ref           : ${{ env.GITHUB_EVENT_REF_SLUG_URL }}"
+    echo "   repository          : ${{ env.GITHUB_REPOSITORY_SLUG_URL }}"
     echo "Short SHA variables"
-    echo "   sha        : ${{ env.GITHUB_SHA_SHORT }}"
+    echo "   sha                 : ${{ env.GITHUB_SHA_SHORT }}"
+    echo "   pull request sha    : ${{ env.GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT }}"
 ```
 
 Read [default environment variables][3] page for more information.
@@ -98,6 +99,15 @@ The commit SHA that triggered the workflow
 | ---------------------------------------- | ---------------- |
 | ffac537e6cbbf934b08745a378932722df287a53 | ffac537e         |
 
+### GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT
+
+Short the value of `github.event.pull_request.head.sha` that represents the last commit
+used for triggering an action for a pull request.
+
+| github.event.pull_request.head.sha       | GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT |
+| ---------------------------------------- | ---------------------------------------- |
+| ffac537e6cbbf934b08745a378932722df287a53 | ffac537e                                 |
+
 ### Use slug variable in an URL
 
 In an URL, use `<GITHUB_VARIABLE>_SLUG_URL` instead of **<GITHUB_VARIABLE>\_SLUG** as subdomain to be compliant.

src/main.ts

@@ -26,6 +26,8 @@ const GITHUB_BASE_REF_SLUG_URL = 'GITHUB_BASE_REF_SLUG_URL'
 const GITHUB_SHA_SHORT = 'GITHUB_SHA_SHORT'
 const GITHUB_EVENT_REF_SLUG = 'GITHUB_EVENT_REF_SLUG'
 const GITHUB_EVENT_REF_SLUG_URL = 'GITHUB_EVENT_REF_SLUG_URL'
+const GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT =
+  'GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT'
 
 async function run(): Promise<void> {
   try {
@@ -38,6 +40,11 @@ async function run(): Promise<void> {
           GITHUB_EVENT_REF_SLUG_URL,
           slugurlref(eventData.ref)
         )
+      } else if (eventData.hasOwnProperty('pull_request')) {
+        core.exportVariable(
+          GITHUB_EVENT_PULL_REQUEST_HEAD_SHA_SHORT,
+          shortsha(eventData.pull_request.head.sha)
+        )
       }
     }