jenkins: run tests when certain files change (#33682)

* test

* change

* work?

* debug

* git

* temp

* save

* test

* test

* work?

* fix

* test

* cleanup

* fix

* final test

* fix

* clean

* null

* final

* test

* save

* test this

* final

Jenkinsfile

@@ -89,7 +89,12 @@ def deviceStage(String stageName, String deviceType, List extra_env, def steps)
             device(device_ip, "git checkout", extra + "\n" + readFile("selfdrive/test/setup_device_ci.sh"))
           }
           steps.each { item ->
-            device(device_ip, item[0], item[1])
+            if (branch != "master" && item.size() == 3 && !hasPathChanged(item[2])) {
+              println "Skipping ${item[0]}: no changes in ${item[2]}."
+              return;
+            } else {
+              device(device_ip, item[0], item[1])
+            }
           }
         }
       }
@@ -97,6 +102,31 @@ def deviceStage(String stageName, String deviceType, List extra_env, def steps)
   }
 }
 
+@NonCPS
+def hasPathChanged(List<String> paths) {
+  changedFiles = []
+  for (changeLogSet in currentBuild.changeSets) {
+    for (entry in changeLogSet.getItems()) {
+      for (file in entry.getAffectedFiles()) {
+        changedFiles.add(file.getPath())
+      }
+    }
+  }
+
+  env.CHANGED_FILES = changedFiles.join(" ")
+  if (currentBuild.number > 1) {
+    env.CHANGED_FILES += currentBuild.previousBuild.getBuildVariables().get("CHANGED_FILES")
+  }
+
+  for (path in paths) {
+    if (env.CHANGED_FILES.contains(path)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 def setupCredentials() {
   withCredentials([
     string(credentialsId: 'azure_token', variable: 'AZURE_TOKEN'),