(struts-site) 01/01: ci: skip staging site build when a PR changes no site files

[lukaszlenart]

This is an automated email from the ASF dual-hosted git repository.

lukaszlenart pushed a commit to branch 
ci/skip-staging-build-when-no-site-changes
in repository https://gitbox.apache.org/repos/asf/struts-site.git

commit 916aab59d68cc79490e41b78ae6085212c2c2e02
Author: Lukasz Lenart <lukaszlen...@apache.org>
AuthorDate: Wed Jul 1 09:53:13 2026 +0200

    ci: skip staging site build when a PR changes no site files
    
    The Struts-site multibranch job rebuilt Jekyll and pushed to asf-staging
    on every PR, even PRs that touch only CI/docs and leave source/ untouched,
    producing an identical staged site. Add a 'Check for site changes' stage
    that diffs a PR against its target branch and sets SITE_CHANGED; gate the
    build, deploy, and PR-comment stages on it. Branch builds (main) always
    rebuild. Skipped stages still report success, so any required check stays
    green.
    
    Co-Authored-By: Claude Opus 4.8 <nore...@anthropic.com>
---
 Jenkinsfile | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/Jenkinsfile b/Jenkinsfile
index ee06965dd..1e0e244e1 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -16,7 +16,31 @@ pipeline {
     PATH="${GEM_HOME}/bin:${RUBY_PATH}/bin:${env.PATH}"
   }
   stages {
+    stage('Check for site changes') {
+      steps {
+        script {
+          if (env.CHANGE_TARGET) {
+            // PR build: only rebuild when files that affect the generated 
site changed.
+            sh "git fetch --no-tags origin 
+refs/heads/${env.CHANGE_TARGET}:refs/remotes/origin/${env.CHANGE_TARGET}"
+            def files = sh(
+                script: "git diff --name-only 
origin/${env.CHANGE_TARGET}...HEAD",
+                returnStdout: true).trim()
+            echo "Files changed in this PR:\n${files}"
+            env.SITE_CHANGED = files.readLines().any {
+              it ==~ /^(source\/.*|_config\.yml|Gemfile(\.lock)?)$/
+            } ? 'true' : 'false'
+          } else {
+            // Branch build (e.g. main): always rebuild.
+            env.SITE_CHANGED = 'true'
+          }
+          echo "SITE_CHANGED=${env.SITE_CHANGED}"
+        }
+      }
+    }
     stage('Build a staged website') {
+      when {
+        expression { env.SITE_CHANGED == 'true' }
+      }
       steps {
         sh '''
           echo Generating a new version of website
@@ -29,6 +53,9 @@ pipeline {
       }
     }
     stage('Deploy to stage area') {
+      when {
+        expression { env.SITE_CHANGED == 'true' }
+      }
       steps {
         sh '''
           echo "Pushing changes into stage site"
@@ -55,7 +82,10 @@ pipeline {
     }
     stage('Comment on PR') {
       when {
-        changeRequest()
+        allOf {
+          changeRequest()
+          expression { env.SITE_CHANGED == 'true' }
+        }
       }
       steps {
         script {