Fix npe for searchable types which no longer exist because the plugin that provided the type was deleted

gradle/changelog/npe_searchable_types.yaml

@@ -0,0 +1,2 @@
+- type: fixed
+  description: NPE for searchable types

scm-webapp/src/main/java/sonia/scm/search/SearchableTypeResolver.java

@@ -86,6 +86,9 @@ class SearchableTypeResolver {
   }
 
   public LuceneSearchableType resolve(Class<?> type) {
+    if (type == null) {
+      throw notFound(entity("type", "null"));
+    }
     LuceneSearchableType searchableType = classToSearchableType.get(type);
     if (searchableType == null) {
       throw notFound(entity("type", type.getName()));

scm-webapp/src/test/java/sonia/scm/search/SearchableTypeResolverTest.java

@@ -0,0 +1,43 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.search;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.junit.jupiter.MockitoExtension;
+import sonia.scm.NotFoundException;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+@ExtendWith(MockitoExtension.class)
+class SearchableTypeResolverTest {
+
+  private final SearchableTypeResolver resolver = new SearchableTypeResolver();
+
+  @Test
+  void shouldThrowNotFoundForNullValue() {
+    assertThrows(NotFoundException.class, () -> resolver.resolve(null));
+  }
+}