GHA: Only execute nightly if changes made (#5289)

Task/Issue URL:
https://app.asana.com/0/1174433894299346/1208527152986496

### Description
Currently we make nightly releases daily, even if there are no new
changes in develop.
This PR fixes that, so we only make nightly releases when there are new
commits since the last tag.

### Steps to test this PR
See task for examples of runs

.github/actions/check-for-changes-since-tag/action.yml

@@ -0,0 +1,28 @@
+name: 'Check for code changes after a specific tag'
+description: 'Checks if there are any new commits to the develop branch since the specified tag'
+
+inputs:
+  tag:
+    description: 'Tag to check'
+    required: true
+
+outputs:
+  has_changes:
+    description: Whether there are new commits since the last tag
+    value: ${{ steps.check_for_changes.outputs.has_changes }}
+
+runs:
+  using: 'composite'
+  steps:
+    - id: check_for_changes
+      shell: bash
+      run: |      
+        # Check if there are any new commits since the tag
+        new_commits=$(git rev-list ${{ inputs.tag }}..develop --count)
+        echo "$new_commits commits since ${{ inputs.tag }} tag"
+        
+        if [ $new_commits -gt 0 ]; then        
+          echo "has_changes=true" >> $GITHUB_OUTPUT
+        else
+          echo "has_changes=false" >> $GITHUB_OUTPUT
+        fi

.github/workflows/release_nightly.yml

@@ -48,71 +48,101 @@ jobs:
           echo "Latest tag: $output"
           echo "latest_tag=$output" >> $GITHUB_OUTPUT
 
+      - name: Check for changes
+        id: check_for_changes
+        uses: ./.github/actions/check-for-changes-since-tag
+        with:
+           github_token: ${{ secrets.GT_DAXMOBILE }}
+           tag: ${{ steps.get_latest_tag.outputs.latest_tag }}
+
+      - name: Notify if no changes
+        if: steps.check_for_changes.outputs.has_changes == 'false'
+        run: |
+          echo "No new commits since the last tag. Skipping nightly release."
+          echo "No new commits since the last tag. Skipping nightly release." >> $GITHUB_STEP_SUMMARY
+          exit 0   
+
       - name: Decode upload keys
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         uses: davidSchuppa/base64Secret-toFile-action@199e78f212c854d2284fada7f3cd3aba3e37d208
         with:
           secret: ${{ secrets.UPLOAD_RELEASE_PROPERTIES }}
           fileName: ddg_android_build_upload.properties
           destination-path: $HOME/jenkins_static/com.duckduckgo.mobile.android/
 
       - name: Decode key file
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         uses: davidSchuppa/base64Secret-toFile-action@199e78f212c854d2284fada7f3cd3aba3e37d208
         with:
           secret: ${{ secrets.UPLOAD_RELEASE_KEY }}
           fileName: ddg-upload-keystore.jks
           destination-path: $HOME/jenkins_static/com.duckduckgo.mobile.android/
 
       - name: Decode Play Store credentials file
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         uses: davidSchuppa/base64Secret-toFile-action@199e78f212c854d2284fada7f3cd3aba3e37d208
         with:
           secret: ${{ secrets.UPLOAD_PLAY_CREDENTIALS }}
           fileName: api.json
           destination-path: $HOME/jenkins_static/com.duckduckgo.mobile.android/
 
       - name: Decode Firebase credentials file
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         uses: davidSchuppa/base64Secret-toFile-action@199e78f212c854d2284fada7f3cd3aba3e37d208
         with:
           secret: ${{ secrets.UPLOAD_FIREBASE_CREDENTIALS }}
           fileName: ddg-upload-firebase.json
           destination-path: $HOME/jenkins_static/com.duckduckgo.mobile.android/
 
       - name: Clean project
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         run: |
           gradle clean          
 
       - name: Assemble the bundle
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         run: gradle bundleInternalRelease -PversionNameSuffix=-nightly -PuseUploadSigning -PlatestTag=${{ steps.get_latest_tag.outputs.latest_tag }}
 
       - name: Generate nightly version name
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         id: generate_version_name
         run: |
           output=$(gradle getBuildVersionName -PversionNameSuffix=-nightly -PlatestTag=${{ steps.get_latest_tag.outputs.latest_tag }} --quiet | tail -n 1)
           echo "version=$output" >> $GITHUB_OUTPUT
 
       - name: Capture App Bundle Path
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         id: capture_output
         run: |
           output=$(find app/build/outputs/bundle/internalRelease -name "*.aab")
           echo "bundle_path=$output" >> $GITHUB_OUTPUT
 
       - name: Upload bundle to Play Store Internal track
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         id: create_app_bundle
         run: |
           bundle exec fastlane deploy_dogfood aab_path:${{ steps.capture_output.outputs.bundle_path }}
 
       - name: Tag Nightly release
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         id: tag_nightly_release
         run: |
           git checkout develop
           git tag -a ${{ steps.generate_version_name.outputs.version }} -m "Create tag ${{ steps.generate_version_name.outputs.version }} for nightly release."
           git push origin ${{ steps.generate_version_name.outputs.version }}
 
       - name: Upload APK as artifact
+        if: steps.check_for_changes.outputs.has_changes == 'true'
         uses: actions/upload-artifact@v4
         with:
           name: duckduckgo-${{ steps.generate_version_name.outputs.version }}.apk
           path: duckduckgo.apk
 
+      - name: Set successful summary
+        if: steps.check_for_changes.outputs.has_changes == 'true'
+        run: |
+          echo "### Nightly release completed! :rocket:" >> $GITHUB_STEP_SUMMARY    
+
       - name: Create Asana task when workflow failed
         if: ${{ failure() }}
         uses: duckduckgo/[email protected]