Fix M3D import crash and memory leak.

The same default material pointer was assigned to all the materials in the scene, so poor destructor tried to free the same pointer multiple times.

code/AssetLib/M3D/M3DImporter.cpp

@@ -233,12 +233,12 @@ void M3DImporter::importMaterials(const M3DWrapper &m3d) {
     ASSIMP_LOG_DEBUG("M3D: importMaterials ", mScene->mNumMaterials);
 
     // add a default material as first
-    aiMaterial *mat = new aiMaterial;
-    mat->AddProperty(&name, AI_MATKEY_NAME);
+    aiMaterial *defaultMat = new aiMaterial;
+    defaultMat->AddProperty(&name, AI_MATKEY_NAME);
     c.a = 1.0f;
     c.b = c.g = c.r = 0.6f;
-    mat->AddProperty(&c, 1, AI_MATKEY_COLOR_DIFFUSE);
-    mScene->mMaterials[0] = mat;
+    defaultMat->AddProperty(&c, 1, AI_MATKEY_COLOR_DIFFUSE);
+    mScene->mMaterials[0] = defaultMat;
 
     if (!m3d->nummaterial || !m3d->material) {
         return;
@@ -300,12 +300,12 @@ void M3DImporter::importMaterials(const M3DWrapper &m3d) {
                     m->prop[j].value.textureid < m3d->numtexture &&
                     m3d->texture[m->prop[j].value.textureid].name) {
                 name.Set(std::string(std::string(m3d->texture[m->prop[j].value.textureid].name) + ".png"));
-                mat->AddProperty(&name, aiTxProps[k].pKey, aiTxProps[k].type, aiTxProps[k].index);
+                newMat->AddProperty(&name, aiTxProps[k].pKey, aiTxProps[k].type, aiTxProps[k].index);
                 n = 0;
-                mat->AddProperty(&n, 1, _AI_MATKEY_UVWSRC_BASE, aiProps[k].type, aiProps[k].index);
+                newMat->AddProperty(&n, 1, _AI_MATKEY_UVWSRC_BASE, aiProps[k].type, aiProps[k].index);
             }
         }
-        mScene->mMaterials[i + 1] = mat;
+        mScene->mMaterials[i + 1] = newMat;
     }
 }
 

test/unit/utM3DImportExport.cpp

@@ -50,35 +50,32 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 using namespace Assimp;
 
-class utM3DImportExport : public AbstractImportExportBase {
-public:
-	bool importerTest() override  {
-        Assimp::Importer importer;
-        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/M3D/cube_normals.m3d", aiProcess_ValidateDataStructure);
+TEST(utM3DImportExport, import_cube_normals) {
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/M3D/cube_normals.m3d", aiProcess_ValidateDataStructure);
 #ifndef ASSIMP_BUILD_NO_M3D_IMPORTER
-		return nullptr != scene;
+    ASSERT_NE(nullptr, scene);
 #else
-        return nullptr == scene;
+    ASSERT_EQ(nullptr, scene);
 #endif // ASSIMP_BUILD_NO_M3D_IMPORTER
-    }
-
-#ifndef ASSIMP_BUILD_NO_EXPORT
-    bool exporterTest() override {
-		Assimp::Importer importer;
-		const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/M3D/cube_normals.m3d", aiProcess_ValidateDataStructure);
-		Exporter exporter;
-		aiReturn ret = exporter.Export(scene, "m3d", ASSIMP_TEST_MODELS_DIR "/M3D/cube_normals_out.m3d");
-		return ret == AI_SUCCESS;
-    }
-#endif
-};
+}
 
-TEST_F(utM3DImportExport, importM3DFromFileTest) {
-    EXPECT_TRUE(importerTest());
+TEST(utM3DImportExport, import_cube_usemtl) {
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/M3D/cube_usemtl.m3d", aiProcess_ValidateDataStructure);
+#ifndef ASSIMP_BUILD_NO_M3D_IMPORTER
+    ASSERT_NE(nullptr, scene);
+#else
+    ASSERT_EQ(nullptr, scene);
+#endif // ASSIMP_BUILD_NO_M3D_IMPORTER
 }
 
 #ifndef ASSIMP_BUILD_NO_EXPORT
-TEST_F(utM3DImportExport, exportM3DFromFileTest) {
-	EXPECT_TRUE(exporterTest());
+TEST(utM3DImportExport, export_cube_normals) {
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/M3D/cube_normals.m3d", aiProcess_ValidateDataStructure);
+    Exporter exporter;
+    aiReturn ret = exporter.Export(scene, "m3d", ASSIMP_TEST_MODELS_DIR "/M3D/cube_normals_out.m3d");
+    ASSERT_EQ(AI_SUCCESS, ret);
 }
 #endif //  ASSIMP_BUILD_NO_EXPORT