[JENKINS-49170] NPE can be thrown on null triggers list

Protect about possible null value for the triggers attribute. This shouldn't be possible now with the current code, so I suppose from reading the code and doing some archeology that it was not 100% protected before 3ad2875 for instance where I see some defensive checks were added. Protecting against this seen in production: ``` java.lang.NullPointerException at org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty.stopTriggers(PipelineTriggersJobProperty.java:96) at org.jenkinsci.plugins.workflow.job.WorkflowJob.removeProperty(WorkflowJob.java:580) at hudson.model.Job.removeProperty(Job.java:535) at org.jenkinsci.plugins.workflow.job.WorkflowJob.setTriggers(WorkflowJob.java:540) ```
jenkinsci · Jan 25, 2018 · 9906156 · 9906156
1 parent 5edc739
commit 9906156
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/src/main/java/org/jenkinsci/plugins/workflow/job/properties/PipelineTriggersJobProperty.java b/src/main/java/org/jenkinsci/plugins/workflow/job/properties/PipelineTriggersJobProperty.java
@@ -70,6 +70,15 @@ public PipelineTriggersJobProperty(List<Trigger> triggers) {
         }
     }
 
+    @SuppressWarnings("unused") // called by deserialization
+    protected Object readResolve() {
+        if (triggers == null) {
+            LOGGER.log(Level.WARNING, "triggers attribute was null, this shouldn't happen.");
+            this.triggers = new ArrayList<>();
+        }
+        return this;
+    }
+
     public void setTriggers(List<Trigger<?>> triggers) {
         this.triggers = new ArrayList<>(triggers);
     }