Add steps to check if there is any source code changed in the incoming pull request.

.github/workflows/PR-content-check.yml

@@ -0,0 +1,34 @@
+# This workflow will build a Java project with Maven
+# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-maven
+
+name: PR Content Check
+
+on:
+  workflow_call:
+    outputs:
+      result:
+        description: "The result of PR content check"
+        value: ${{ jobs.check-PR-content.outputs.output1 }}
+
+jobs:
+  check-PR-content:
+    name: Check PR Content
+
+    runs-on: ubuntu-latest
+
+    outputs:
+      output1: ${{ steps.check-content.outputs.result }}
+
+    steps:
+      - name: Checkout the incoming pull request
+        uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+          fetch-depth: 0
+          path: ion-java-new
+
+      - name: Check the content of the last commit
+        id: check-content
+        run: |
+          cd ion-java-new
+          if [[ $(git log -1 --name-only) == *"src/"* ]]; then echo "result=pass" >> $GITHUB_OUTPUT; else echo "result=fail" >> $GITHUB_OUTPUT; fi

.github/workflows/ion-java-performance-regression-detector.yml

@@ -6,9 +6,13 @@ name: Ion Java performance regression detector
 on: [pull_request]
 
 jobs:
+  PR-Content-Check:
+    uses: amazon-ion/ion-java/.github/workflows/PR-content-check.yml@master
+
   detect-regression:
     name: Detect Regression
-
+    needs: PR-Content-Check
+    if: ${{ needs.PR-Content-Check.outputs.result == 'pass' }}
     runs-on: ubuntu-latest
 
     steps:
@@ -18,7 +22,7 @@ jobs:
           java-version: 1.8
 
       - name: Checkout ion-java from the new commit.
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           ref: ${{ github.event.pull_request.head.sha }}
           path: ion-java-new
@@ -27,7 +31,7 @@ jobs:
         run: cd ion-java-new && git submodule init && git submodule update && ./gradlew clean publishToMavenLocal
 
       - name: Checkout ion-java-benchmark-cli
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           repository: amazon-ion/ion-java-benchmark-cli
           ref: master
@@ -70,7 +74,7 @@ jobs:
         run : rm -r /home/runner/.m2
 
       - name: Checkout the current commit
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           repository: amazon-ion/ion-java
           ref: master

.github/workflows/ion-test-driver.yml

@@ -3,8 +3,13 @@ name: ion-test-driver
 on: [pull_request]
 
 jobs:
+  PR-Content-Check:
+    uses: amazon-ion/ion-java/.github/workflows/PR-content-check.yml@master
+
   ion-test-driver:
     runs-on: macos-10.15
+    needs: PR-Content-Check
+    if: ${{ needs.PR-Content-Check.outputs.result == 'pass' }}
     steps:
       - name: Checkout ion-java
         uses: actions/checkout@master