Add regression for ambiguous enum simple-name linking

Ensures the call graph and linker fail closed when multiple enums share the same simple name across packages and bindings are unavailable.

Co-authored-by: Cursor <cursoragent@cursor.com>

state_machine_exporter/src/test/java/click/kamil/springstatemachineexporter/analysis/service/AmbiguousSimpleEnumLinkingTest.java

@@ -0,0 +1,97 @@
+package click.kamil.springstatemachineexporter.analysis.service;
+
+import click.kamil.springstatemachineexporter.analysis.enricher.TransitionLinkerEnricher;
+import click.kamil.springstatemachineexporter.analysis.model.AnalysisResult;
+import click.kamil.springstatemachineexporter.analysis.model.CallChain;
+import click.kamil.springstatemachineexporter.analysis.model.CodebaseMetadata;
+import click.kamil.springstatemachineexporter.analysis.model.EntryPoint;
+import click.kamil.springstatemachineexporter.analysis.model.LinkResolution;
+import click.kamil.springstatemachineexporter.analysis.model.TriggerPoint;
+import click.kamil.springstatemachineexporter.ast.common.CodebaseContext;
+import click.kamil.springstatemachineexporter.model.Event;
+import click.kamil.springstatemachineexporter.model.State;
+import click.kamil.springstatemachineexporter.model.Transition;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Regression: when two enums share the same simple name across packages, we must not expand or link
+ * by guessing which enum {@code OrderEvent} refers to when bindings are unavailable.
+ */
+class AmbiguousSimpleEnumLinkingTest {
+
+    @Test
+    void shouldFailClosedWhenEnumSimpleNameIsAmbiguousAcrossPackages(@TempDir Path tempDir) throws Exception {
+        Files.createDirectories(tempDir.resolve("a"));
+        Files.createDirectories(tempDir.resolve("b"));
+        Files.writeString(tempDir.resolve("a/OrderEvent.java"),
+                "package a; public enum OrderEvent { PAY, SHIP }");
+        Files.writeString(tempDir.resolve("b/OrderEvent.java"),
+                "package b; public enum OrderEvent { CANCEL }");
+        Files.writeString(tempDir.resolve("App.java"), """
+                package com.example;
+                import a.OrderEvent;
+                public class OrderController {
+                    Dispatcher dispatcher = new Dispatcher();
+                    public void transition(String eventStr) {
+                        dispatcher.dispatch(eventStr);
+                    }
+                }
+                class Dispatcher {
+                    void dispatch(String eventStr) {
+                        StateMachine sm = new StateMachine();
+                        // Unresolved valueOf(arg) must not expand to a concrete enum set via simple-name lookup.
+                        sm.sendEvent(OrderEvent.valueOf(eventStr));
+                    }
+                }
+                class StateMachine { void sendEvent(OrderEvent e) {} }
+                """);
+
+        CodebaseContext context = new CodebaseContext();
+        // Keep bindings off so type printing stays import-style and we rely on scan-time indexes.
+        context.setResolveBindings(false);
+        context.scan(tempDir);
+
+        HeuristicCallGraphEngine engine = new HeuristicCallGraphEngine(context);
+        EntryPoint entry = EntryPoint.builder()
+                .className("com.example.OrderController")
+                .methodName("transition")
+                .build();
+        TriggerPoint trigger = TriggerPoint.builder()
+                .className("com.example.StateMachine")
+                .methodName("sendEvent")
+                .event("e")
+                .build();
+
+        CallChain chain = engine.findChains(List.of(entry), List.of(trigger)).get(0);
+
+        Transition pay = new Transition();
+        pay.setSourceStates(List.of(State.of("NEW", "NEW")));
+        pay.setTargetStates(List.of(State.of("PAID", "PAID")));
+        pay.setEvent(Event.of("PAY", "a.OrderEvent.PAY"));
+
+        Transition ship = new Transition();
+        ship.setSourceStates(List.of(State.of("PAID", "PAID")));
+        ship.setTargetStates(List.of(State.of("SHIPPED", "SHIPPED")));
+        ship.setEvent(Event.of("SHIP", "a.OrderEvent.SHIP"));
+
+        AnalysisResult result = AnalysisResult.builder()
+                .name("com.example.OrderStateMachineConfig")
+                .transitions(List.of(pay, ship))
+                .metadata(CodebaseMetadata.builder().callChains(List.of(chain)).build())
+                .build();
+
+        new TransitionLinkerEnricher().enrich(result, context, null);
+
+        CallChain linked = result.getMetadata().getCallChains().get(0);
+        assertThat(linked.getMatchedTransitions()).isNullOrEmpty();
+        assertThat(linked.getLinkResolution()).isIn(LinkResolution.NO_MATCH, LinkResolution.AMBIGUOUS_WIDEN);
+    }
+}
+