Prevent NPE when IntroduceSuggestionHint generates a method apache#6258

- apache#6258
- Find a position for the curl open brace `{` when a type element doesn't have other elements
```php
<?php
// e.g.
class Test {
}
```
- Add unit tests

php/php.editor/src/org/netbeans/modules/php/editor/verification/IntroduceSuggestion.java

@@ -991,8 +991,12 @@ private static int getOffsetAfterNextTokenId(BaseDocument doc, int offset, PHPTo
      * @return The offset after the last use trait statement if traits are used,
      * otherwise the offset after the open curly for the type
      */
-    private static int getOffsetAfterUseTrait(BaseDocument document, TypeScope typeScope) {
+    private static int getOffsetAfterUseTrait(BaseDocument document, TypeScope typeScope) throws BadLocationException {
         OffsetRange blockRange = typeScope.getBlockRange();
+        if (blockRange == null) {
+            // GH-6258 Block range of ClassScope created from ClassElement is null
+            return getOffsetAfterClassOpenCurly(document, typeScope.getOffset());
+        }
         int offset = blockRange.getEnd() - 1; // before close curly "}"
         Collection<ModelElement> elements = new HashSet<>();
         elements.addAll(typeScope.getDeclaredMethods());

php/php.editor/test/unit/data/testfiles/verification/IntroduceSuggestion/testGH6258/TestClass.php

@@ -0,0 +1,21 @@
+<?php
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+class TestClass {
+}

php/php.editor/test/unit/data/testfiles/verification/IntroduceSuggestion/testGH6258/testGH6258_01.php

@@ -0,0 +1,20 @@
+<?php
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+TestClass::generatedMethod();

php/php.editor/test/unit/data/testfiles/verification/IntroduceSuggestion/testGH6258/testGH6258_01.php.testGH6258_01.hints

@@ -0,0 +1,4 @@
+TestClass::generatedMeth^od();
+----------------------------
+HINT:Introduce Hint
+FIX:Create Method " generatedMethod()" in Class "TestClass" (TestClass.php)

php/php.editor/test/unit/data/testfiles/verification/IntroduceSuggestion/testGH6258/testGH6258_01.php.testGH6258_01Fix.fixed

@@ -0,0 +1,20 @@
+<?php
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+TestClass::generatedMethod();

php/php.editor/test/unit/data/testfiles/verification/IntroduceSuggestion/testGH6258/testGH6258_02.php

@@ -0,0 +1,21 @@
+<?php
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+$test = new TestClass();
+$test->generatedMethod();

php/php.editor/test/unit/data/testfiles/verification/IntroduceSuggestion/testGH6258/testGH6258_02.php.testGH6258_02.hints

@@ -0,0 +1,4 @@
+$test->generatedMet^hod();
+------------------------
+HINT:Introduce Hint
+FIX:Create Method " generatedMethod()" in Class "TestClass" (TestClass.php)

php/php.editor/test/unit/data/testfiles/verification/IntroduceSuggestion/testGH6258/testGH6258_02.php.testGH6258_02Fix.fixed

@@ -0,0 +1,21 @@
+<?php
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+$test = new TestClass();
+$test->generatedMethod();

php/php.editor/test/unit/src/org/netbeans/modules/php/editor/verification/IntroduceSuggestionTest.java

@@ -307,14 +307,42 @@ public void testEnumMethods_Fix06() throws Exception {
         applyHint("BackedEnumString::Case2::introdu^ceStaticMethod();", "Create Method");
     }
 
+    public void testGH6258_01() throws Exception {
+        checkHints("testGH6258_01.php", "TestClass::generatedMeth^od();");
+    }
+
+    public void testGH6258_01Fix() throws Exception {
+        // no changes because the method is created into the TestClass
+        // check that NPE doesn't occur
+        applyHint("testGH6258_01.php", "TestClass::generatedMeth^od();", "Create Method");
+    }
+
+    public void testGH6258_02() throws Exception {
+        checkHints("testGH6258_02.php", "$test->generatedMet^hod();");
+    }
+
+    public void testGH6258_02Fix() throws Exception {
+        // no changes because the method is created into the TestClass
+        // check that NPE doesn't occur
+        applyHint("testGH6258_02.php", "$test->generatedMetho^d();", "Create Method");
+    }
+
     private void checkHints(String caretLine) throws Exception {
         checkHints(new IntroduceSuggestion(), getTestFileName(), caretLine);
     }
 
+    private void checkHints(String fileName, String caretLine) throws Exception {
+        checkHints(new IntroduceSuggestion(), fileName, caretLine);
+    }
+
     private void applyHint(String caretLine, String fixDesc) throws Exception {
         applyHint(new IntroduceSuggestion(), getTestFileName(), caretLine, fixDesc);
     }
 
+    private void applyHint(String fileName, String caretLine, String fixDesc) throws Exception {
+        applyHint(new IntroduceSuggestion(), fileName, caretLine, fixDesc);
+    }
+
     private void fixContent(File file) throws Exception {
         Path path = file.toPath();
         Charset charset = StandardCharsets.UTF_8;