Add option to allow returning nullable from methods in

Jsr305AnnotationCheck #887

Author: vdaniloff

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/Jsr305AnnotationsCheck.java

@@ -329,6 +329,8 @@ private enum NullnessAnnotation {
     private boolean allowOverridingReturnValue;
     /** Parameter: overriding parameter annotations allowed. */
     private boolean allowOverridingParameter;
+    /** Parameter: allow nullable return value. */
+    private boolean allowNullableReturnValue;
 
     /** State, is a package excluded. */
     private boolean packageExcluded;
@@ -415,6 +417,16 @@ public void setAllowOverridingParameter(final boolean newAllowOverridingParamete
         allowOverridingParameter = newAllowOverridingParameter;
     }
 
+    /**
+     * Sets the property for allowing nullable return values.
+     *
+     * @param newAllowNullableReturnValue
+     *        true if yes
+     */
+    public void setAllowNullableReturnValue(final boolean newAllowNullableReturnValue) {
+        allowNullableReturnValue = newAllowNullableReturnValue;
+    }
+
     /**
      * Maps annotations to their respective names.
      *
@@ -771,8 +783,10 @@ protected MethodJsr305Handler(final DetailAST ast) {
         protected void runReturnAnnotationHandler() {
             checkContainsAny(MSG_RETURN_VALUE_WITH_NONNULL_BY_DEFAULT,
                     NullnessAnnotation.RETURN_VALUES_ARE_NONNULL_BY_DEFAULT);
-            checkContainsAny(MSG_RETURN_VALUE_WITH_NULLABLE,
+            if (!allowNullableReturnValue) {
+                checkContainsAny(MSG_RETURN_VALUE_WITH_NULLABLE,
                     NullnessAnnotation.NULLABLE);
+            }
             checkContainsAll(MSG_CONTRADICTING_RETURN_VALUE_ANNOTATIONS, NullnessAnnotation.NONNULL,
                     NullnessAnnotation.CHECK_FOR_NULL);
             checkContainsAll(MSG_OVERRIDDEN_METHOD_WITH_CHECK_RETURN_VALUE,

sevntu-checks/src/test/java/com/github/sevntu/checkstyle/checks/coding/Jsr305AnnotationsCheckTest.java

@@ -407,4 +407,34 @@ public void testNestedAnnotations() throws Exception {
                 expected);
     }
 
+    @Test
+    public void testAllowNullableReturn() throws Exception {
+        final DefaultConfiguration checkConfig = createModuleConfig(Jsr305AnnotationsCheck.class);
+        checkConfig.addAttribute("packages", "com.github.sevntu.checkstyle.checks.coding");
+        checkConfig.addAttribute("allowNullableReturnValue", "true");
+
+        final String[] expected = {
+            "51:5: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_CONTRADICTING_RETURN_VALUE_ANNOTATIONS, "e"),
+            "69:5: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_PRIMITIVES_WITH_NULLNESS_ANNOTATION, "e"),
+            "75:5: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_PRIMITIVES_WITH_NULLNESS_ANNOTATION, "e"),
+            "92:5: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_CONTRADICTING_CLASS_LEVEL_ANNOTATIONS, "e"),
+            "95:26: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_PARAMETER_WITHOUT_NULLNESS_ANNOTATION, "e"),
+            "95:48: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_PARAMETER_WITHOUT_NULLNESS_ANNOTATION, "e"),
+            "99:5: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_OVERRIDDEN_METHOD_WITH_CHECK_RETURN_VALUE, "e"),
+            "105:5: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_VOID_WITH_CHECK_RETURN_VALUE_ANNOTATION, "e"),
+            "110:5: " + getCheckMessage(
+                Jsr305AnnotationsCheck.MSG_PRIMITIVES_WITH_NULLNESS_ANNOTATION, "e"),
+        };
+
+        verify(checkConfig, getPath("InputJsr305AnnotationsCheckWithReturnValue.java"), expected);
+    }
+
 }