Add strict export mode to propagate export failures as exceptions

plugin/src/main/java/io/jenkins/plugins/casc/Attribute.java

@@ -241,8 +241,14 @@ public Type getValue(Owner target) throws Exception {
     public CNode describe(Owner instance, ConfigurationContext context) throws ConfiguratorException {
         final Configurator c = context.lookup(type);
         if (c == null) {
-            return new Scalar("FAILED TO EXPORT\n" + instance.getClass().getName() + "#" + name
-                    + ": No configurator found for type " + type);
+            String errorMessage = "FAILED TO EXPORT\n" + instance.getClass().getName() + "#" + name
+                    + ": No configurator found for type " + type;
+
+            if (context.isStrictExport()) {
+                throw new ConfiguratorException(errorMessage);
+            }
+
+            return new Scalar(errorMessage);
         }
         try {
             Object o = getValue(instance);
@@ -267,7 +273,14 @@ public CNode describe(Owner instance, ConfigurationContext context) throws Confi
                 return seq;
             }
             return _describe(c, context, o, shouldBeMasked);
-        } catch (Exception | /* Jenkins.getDescriptorOrDie */ AssertionError e) {
+        } catch (Exception | AssertionError e) {
+            if (context.isStrictExport()) {
+                if (e instanceof ConfiguratorException) {
+                    throw (ConfiguratorException) e;
+                }
+                throw new ConfiguratorException(
+                        "Failed to export " + instance.getClass().getName() + "#" + name, e);
+            }
             // Don't fail the whole export, prefer logging this error
             LOGGER.log(Level.WARNING, "Failed to export", e);
             return new Scalar(

plugin/src/main/java/io/jenkins/plugins/casc/ConfigurationAsCode.java

@@ -595,10 +595,15 @@ public void doReference(StaplerRequest2 req, StaplerResponse2 res) throws Except
 
     @Restricted(NoExternalUse.class)
     public void export(OutputStream out) throws Exception {
+        export(out, false);
+    }
 
+    @Restricted(NoExternalUse.class)
+    public void export(OutputStream out, boolean strict) throws Exception {
         final List<NodeTuple> tuples = new ArrayList<>();
 
         final ConfigurationContext context = new ConfigurationContext(registry);
+        context.setStrictExport(strict);
         for (RootElementConfigurator root : RootElementConfigurator.all()) {
             final CNode config = root.describe(root.getTargetComponent(context), context);
             final Node valueNode = toYaml(config);

plugin/src/main/java/io/jenkins/plugins/casc/ConfigurationContext.java

@@ -44,6 +44,8 @@ public class ConfigurationContext implements ConfiguratorRegistry {
 
     private transient SecretSourceResolver secretSourceResolver;
 
+    private boolean strictExport = false;
+
     public ConfigurationContext(ConfiguratorRegistry registry) {
         this(registry, null);
     }
@@ -126,6 +128,14 @@ public int getYamlCodePointLimit() {
         return yamlCodePointLimit;
     }
 
+    public boolean isStrictExport() {
+        return strictExport;
+    }
+
+    public void setStrictExport(boolean strictExport) {
+        this.strictExport = strictExport;
+    }
+
     // --- delegate methods for ConfigurationContext
 
     @Override

plugin/src/test/java/io/jenkins/plugins/casc/AttributeTest.java

@@ -1,9 +1,15 @@
 package io.jenkins.plugins.casc;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import edu.umd.cs.findbugs.annotations.NonNull;
 import hudson.util.Secret;
+import io.jenkins.plugins.casc.model.CNode;
+import io.jenkins.plugins.casc.model.Scalar;
+import java.lang.reflect.Type;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import org.junit.jupiter.api.AfterEach;
@@ -230,4 +236,51 @@ void checkCalculationIsIdempotent() {
         assertFalse(firstUnknown);
         assertFalse(secondUnknown, "Subsequent calls should return the same fallback FALSE result");
     }
+
+    @Test
+    @SuppressWarnings("ExtractMethodRecommender")
+    void describeHandlesMissingConfiguratorCorrectly() throws Exception {
+        ConfiguratorRegistry dummyRegistry = new ConfiguratorRegistry() {
+            @Override
+            public RootElementConfigurator<?> lookupRootElement(String name) {
+                return null;
+            }
+
+            @Override
+            @NonNull
+            public <T> Configurator<T> lookupOrFail(Type type) throws ConfiguratorException {
+                throw new ConfiguratorException("Not found");
+            }
+
+            @Override
+            public <T> Configurator<T> lookup(Type type) {
+                return null;
+            }
+        };
+
+        ConfigurationContext context = new ConfigurationContext(dummyRegistry);
+
+        Attribute<NonSecretField, String> attr = new Attribute<>("passwordPath", String.class);
+        NonSecretField dummyInstance = new NonSecretField("my-dummy-path");
+
+        context.setStrictExport(false);
+        CNode node = attr.describe(dummyInstance, context);
+
+        assertInstanceOf(Scalar.class, node, "Should return a Scalar node on failure in non-strict mode");
+        assertTrue(
+                ((Scalar) node).getValue().contains("FAILED TO EXPORT"),
+                "Scalar should contain the fallback failure message");
+
+        context.setStrictExport(true);
+        ConfiguratorException exception = assertThrows(
+                ConfiguratorException.class,
+                () -> {
+                    attr.describe(dummyInstance, context);
+                },
+                "Should completely abort and throw ConfiguratorException in strict mode");
+
+        assertTrue(
+                exception.getMessage().contains("No configurator found"),
+                "Exception message should accurately reflect the missing configurator");
+    }
 }

plugin/src/test/java/io/jenkins/plugins/casc/ConfigurationAsCodeApiTest.java

@@ -3,8 +3,11 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertFalse;
 
+import java.io.ByteArrayOutputStream;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.List;
@@ -185,4 +188,18 @@ public void testDoReplace_ValidSource() throws Exception {
             assertThat(j.jenkins.getSystemMessage(), is("Hello Replace"));
         }
     }
+
+    @Test
+    public void testExportStrictMode_SuccessOnCleanJenkins() throws Exception {
+        configureAdminSecurity();
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+
+        ConfigurationAsCode.get().export(out, true);
+
+        String exportedYaml = out.toString(StandardCharsets.UTF_8);
+
+        assertThat(exportedYaml, containsString("jenkins:"));
+        assertFalse(exportedYaml.contains("FAILED TO EXPORT"));
+    }
 }

test-harness/src/main/java/io/jenkins/plugins/casc/misc/JenkinsConfiguredRule.java

@@ -7,22 +7,18 @@
 
 public class JenkinsConfiguredRule extends JenkinsRule {
 
-    // TODO: Looks like API defect, exception should be thrown
     /**
      * Exports the Jenkins configuration to a string.
      * @return YAML as string
      * @param strict Fail if any export operation returns error
      * @throws Exception Export error
-     * @throws AssertionError Failed to export the configuration
      * @since 1.25
      */
     public String exportToString(boolean strict) throws Exception {
         final ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ConfigurationAsCode.get().export(out);
-        final String s = out.toString(StandardCharsets.UTF_8.name());
-        if (strict && s.contains("Failed to export")) {
-            throw new AssertionError("Failed to export the configuration: " + s);
-        }
-        return s;
+
+        ConfigurationAsCode.get().export(out, strict);
+
+        return out.toString(StandardCharsets.UTF_8);
     }
 }