Merge pull request #7543 from MarkEWaite/fix-URICheckEncodingMonitor-NPE

Fix URICheckEncodingMonitor NPE

core/src/main/java/jenkins/diagnostics/URICheckEncodingMonitor.java

@@ -43,7 +43,7 @@ public class URICheckEncodingMonitor extends AdministrativeMonitor {
 
         if (!expected.equals(value)) {
             String expectedHex = Util.toHexString(expected.getBytes(StandardCharsets.UTF_8));
-            String valueHex = Util.toHexString(value.getBytes(StandardCharsets.UTF_8));
+            String valueHex = value != null ? Util.toHexString(value.getBytes(StandardCharsets.UTF_8)) : null;
             LOGGER.log(Level.CONFIG, "Expected to receive: " + expected + " (" + expectedHex + ") but got: " + value + " (" + valueHex + ")");
             return FormValidation.warningWithMarkup(hudson.model.Messages.Hudson_NotUsesUTF8ToDecodeURL());
         }

test/src/test/java/jenkins/diagnostics/URICheckEncodingMonitorTest.java

@@ -0,0 +1,31 @@
+package jenkins.diagnostics;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.is;
+
+import hudson.util.FormValidation;
+import org.junit.Rule;
+import org.junit.Test;
+import org.jvnet.hudson.test.JenkinsRule;
+import org.kohsuke.stapler.Stapler;
+
+public class URICheckEncodingMonitorTest {
+
+    @Rule
+    public JenkinsRule j = new JenkinsRule();
+
+    /* Test that an empty value returned to URICheckEncodingMonitor
+     * does not cause a null pointer exception
+     */
+    @Test
+    public void emptyValueInResponse() throws Exception {
+        j.executeOnServer(() -> {
+                URICheckEncodingMonitor monitor = new URICheckEncodingMonitor();
+                FormValidation validation = monitor.doCheckURIEncoding(Stapler.getCurrentRequest());
+                assertThat(validation.kind, is(FormValidation.Kind.WARNING));
+                assertThat(validation.getMessage(), containsString("Your container doesn’t use UTF-8 to decode URLs."));
+                return null;
+            });
+    }
+}