[JENKINS-72886] fix command & args are lost when combining container templates (#1525)

Author: moleus

src/main/java/org/csanchez/jenkins/plugins/kubernetes/PodTemplateUtils.java

@@ -203,8 +203,12 @@ public static Container combine(@CheckForNull Container parent, @NonNull Contain
         String workingDir = isNullOrEmpty(template.getWorkingDir())
                 ? (isNullOrEmpty(parent.getWorkingDir()) ? DEFAULT_WORKING_DIR : parent.getWorkingDir())
                 : template.getWorkingDir();
-        List<String> command = template.getCommand() == null ? parent.getCommand() : template.getCommand();
-        List<String> args = template.getArgs() == null ? parent.getArgs() : template.getArgs();
+        List<String> command =
+                template.getCommand() == null || template.getCommand().isEmpty()
+                        ? parent.getCommand()
+                        : template.getCommand();
+        List<String> args =
+                template.getArgs() == null || template.getArgs().isEmpty() ? parent.getArgs() : template.getArgs();
         Boolean tty = template.getTty() != null ? template.getTty() : parent.getTty();
         Map<String, Quantity> requests = combineResources(parent, template, ResourceRequirements::getRequests);
         Map<String, Quantity> limits = combineResources(parent, template, ResourceRequirements::getLimits);

src/test/java/org/csanchez/jenkins/plugins/kubernetes/PodTemplateUtilsTest.java

@@ -937,4 +937,16 @@ private static void checkParsed(Pod pod) {
                         .get(0)
                         .getMode());
     }
+
+    @Test
+    @Issue("JENKINS-72886")
+    public void shouldIgnoreContainerEmptyArgs() {
+        Container parent = new Container();
+        parent.setArgs(List.of("arg1", "arg2"));
+        parent.setCommand(List.of("parent command"));
+        Container child = new Container();
+        Container result = combine(parent, child);
+        assertEquals(List.of("arg1", "arg2"), result.getArgs());
+        assertEquals(List.of("parent command"), result.getCommand());
+    }
 }