From a9451b1159522c2203f3788222a678163d78b4ab Mon Sep 17 00:00:00 2001
From: Filip Hrisafov <filip.hrisafov@gmail.com>
Date: Sat, 29 Aug 2020 11:44:13 +0200
Subject: [PATCH] #2185 Fix StackOverflow error when recursive use of mapper in
 Mapper#uses

---
 .../processor/MethodRetrievalProcessor.java   | 21 +++++++--
 .../mapstruct/ap/internal/util/Message.java   |  1 +
 .../ap/test/bugs/_2185/Issue2185Test.java     | 45 ++++++++++++++++++
 .../ap/test/bugs/_2185/TodoMapper.java        | 46 +++++++++++++++++++
 4 files changed, 108 insertions(+), 5 deletions(-)
 create mode 100644 processor/src/test/java/org/mapstruct/ap/test/bugs/_2185/Issue2185Test.java
 create mode 100644 processor/src/test/java/org/mapstruct/ap/test/bugs/_2185/TodoMapper.java

diff --git a/processor/src/main/java/org/mapstruct/ap/internal/processor/MethodRetrievalProcessor.java b/processor/src/main/java/org/mapstruct/ap/internal/processor/MethodRetrievalProcessor.java
index 672d905ee..059a000bc 100644
--- a/processor/src/main/java/org/mapstruct/ap/internal/processor/MethodRetrievalProcessor.java
+++ b/processor/src/main/java/org/mapstruct/ap/internal/processor/MethodRetrievalProcessor.java
@@ -176,11 +176,22 @@ public class MethodRetrievalProcessor implements ModelElementProcessor<Void, Lis
         //Add all methods of used mappers in order to reference them in the aggregated model
         if ( usedMapper.equals( mapperToImplement ) ) {
             for ( DeclaredType mapper : mapperOptions.uses() ) {
-                methods.addAll( retrieveMethods(
-                    asTypeElement( mapper ),
-                    mapperToImplement,
-                    mapperOptions,
-                    prototypeMethods ) );
+                TypeElement usesMapperElement = asTypeElement( mapper );
+                if ( !mapperToImplement.equals( usesMapperElement ) ) {
+                    methods.addAll( retrieveMethods(
+                        usesMapperElement,
+                        mapperToImplement,
+                        mapperOptions,
+                        prototypeMethods ) );
+                }
+                else {
+                    messager.printMessage(
+                        mapperToImplement,
+                        mapperOptions.getAnnotationMirror(),
+                        Message.RETRIEVAL_MAPPER_USES_CYCLE,
+                        mapperToImplement
+                    );
+                }
             }
         }
 
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/util/Message.java b/processor/src/main/java/org/mapstruct/ap/internal/util/Message.java
index 67cd1aba0..6f0db248b 100644
--- a/processor/src/main/java/org/mapstruct/ap/internal/util/Message.java
+++ b/processor/src/main/java/org/mapstruct/ap/internal/util/Message.java
@@ -149,6 +149,7 @@ public enum Message {
     RETRIEVAL_WILDCARD_SUPER_BOUND_SOURCE( "Can't generate mapping method for a wildcard super bound source." ),
     RETRIEVAL_WILDCARD_EXTENDS_BOUND_RESULT( "Can't generate mapping method for a wildcard extends bound result." ),
     RETRIEVAL_CONTEXT_PARAMS_WITH_SAME_TYPE( "The types of @Context parameters must be unique." ),
+    RETRIEVAL_MAPPER_USES_CYCLE( "The mapper %s is referenced itself in Mapper#uses.", Diagnostic.Kind.WARNING ),
 
     INHERITINVERSECONFIGURATION_DUPLICATES( "Several matching inverse methods exist: %s(). Specify a name explicitly." ),
     INHERITINVERSECONFIGURATION_INVALID_NAME( "None of the candidates %s() matches given name: \"%s\"." ),
diff --git a/processor/src/test/java/org/mapstruct/ap/test/bugs/_2185/Issue2185Test.java b/processor/src/test/java/org/mapstruct/ap/test/bugs/_2185/Issue2185Test.java
new file mode 100644
index 000000000..3b26842c0
--- /dev/null
+++ b/processor/src/test/java/org/mapstruct/ap/test/bugs/_2185/Issue2185Test.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._2185;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.WithClasses;
+import org.mapstruct.ap.testutil.compilation.annotation.CompilationResult;
+import org.mapstruct.ap.testutil.compilation.annotation.Diagnostic;
+import org.mapstruct.ap.testutil.compilation.annotation.ExpectedCompilationOutcome;
+import org.mapstruct.ap.testutil.runner.AnnotationProcessorTestRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Filip Hrisafov
+ */
+@IssueKey("2185")
+@RunWith(AnnotationProcessorTestRunner.class)
+@WithClasses({
+    TodoMapper.class
+})
+public class Issue2185Test {
+
+    @Test
+    @ExpectedCompilationOutcome(value = CompilationResult.SUCCEEDED,
+        diagnostics = {
+            @Diagnostic(type = TodoMapper.class,
+                kind = javax.tools.Diagnostic.Kind.WARNING,
+                line = 14,
+                message = "The mapper org.mapstruct.ap.test.bugs._2185.TodoMapper is referenced itself in Mapper#uses.")
+        }
+    )
+    public void shouldCompile() {
+
+        TodoMapper.TodoResponse response = TodoMapper.INSTANCE.toResponse( new TodoMapper.TodoEntity( "test" ) );
+
+        assertThat( response ).isNotNull();
+        assertThat( response.getNote() ).isEqualTo( "test" );
+    }
+}
diff --git a/processor/src/test/java/org/mapstruct/ap/test/bugs/_2185/TodoMapper.java b/processor/src/test/java/org/mapstruct/ap/test/bugs/_2185/TodoMapper.java
new file mode 100644
index 000000000..2d52bed1f
--- /dev/null
+++ b/processor/src/test/java/org/mapstruct/ap/test/bugs/_2185/TodoMapper.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._2185;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.factory.Mappers;
+
+/**
+ * @author Filip Hrisafov
+ */
+@Mapper(uses = TodoMapper.class)
+public interface TodoMapper {
+
+    TodoMapper INSTANCE = Mappers.getMapper( TodoMapper.class );
+
+    TodoResponse toResponse(TodoEntity entity);
+
+    class TodoResponse {
+
+        private final String note;
+
+        public TodoResponse(String note) {
+            this.note = note;
+        }
+
+        public String getNote() {
+            return note;
+        }
+    }
+
+    class TodoEntity {
+
+        private final String note;
+
+        public TodoEntity(String note) {
+            this.note = note;
+        }
+
+        public String getNote() {
+            return note;
+        }
+    }
+}