Add support for WithDefault<string, null>

Summary:
This diff adds support for:

```
propName: WithDefault<string, null>,
```

It will throw if null is used for any other type like boolean

Reviewed By: TheSavior, cpojer

Differential Revision: D15748556

fbshipit-source-id: 925457ca1739bfad08e4776ecb47c0beb3acacf5

packages/react-native-codegen/src/CodegenSchema.js

@@ -45,7 +45,7 @@ type PropTypeTypeAnnotation =
     |}>
   | $ReadOnly<{|
       type: 'StringTypeAnnotation',
-      default: string,
+      default: string | null,
     |}>
   | $ReadOnly<{|
       type: 'FloatTypeAnnotation',

packages/react-native-codegen/src/generators/GeneratePropsH.js

@@ -140,6 +140,9 @@ function convertDefaultTypeToString(componentName: string, prop): string {
     case 'BooleanTypeAnnotation':
       return String(typeAnnotation.default);
     case 'StringTypeAnnotation':
+      if (typeAnnotation.default == null) {
+        return '';
+      }
       return `"${typeAnnotation.default}"`;
     case 'Int32TypeAnnotation':
       return String(typeAnnotation.default);

packages/react-native-codegen/src/generators/GenerateTests.js

@@ -14,9 +14,11 @@ import type {SchemaType} from '../CodegenSchema';
 const {getImports, toSafeCppString} = require('./CppHelpers');
 
 type FilesOutput = Map<string, string>;
+type PropValueType = string | number | boolean;
+
 type TestCase = $ReadOnly<{|
   propName: string,
-  propValue: string | number | boolean,
+  propValue: ?PropValueType,
   testName?: string,
   raw?: boolean,
 |}>;
@@ -59,7 +61,10 @@ function getTestCasesForProp(propName, typeAnnotation) {
   } else if (typeAnnotation.type === 'StringTypeAnnotation') {
     cases.push({
       propName,
-      propValue: typeAnnotation.default || 'foo',
+      propValue:
+        typeAnnotation.default != null && typeAnnotation.default !== ''
+          ? typeAnnotation.default
+          : 'foo',
     });
   } else if (typeAnnotation.type === 'BooleanTypeAnnotation') {
     cases.push({

packages/react-native-codegen/src/generators/__test_fixtures__/fixtures.js

@@ -110,6 +110,14 @@ const STRING_PROP: SchemaType = {
                 default: '',
               },
             },
+            {
+              name: 'accessibilityRole',
+              optional: true,
+              typeAnnotation: {
+                type: 'StringTypeAnnotation',
+                default: null,
+              },
+            },
           ],
         },
       },

packages/react-native-codegen/src/generators/__tests__/__snapshots__/GeneratePropsCpp-test.js.snap

@@ -387,7 +387,8 @@ StringPropComponentProps::StringPropComponentProps(
     const StringPropComponentProps &sourceProps,
     const RawProps &rawProps): ViewProps(sourceProps, rawProps),
 
-    accessibilityHint(convertRawProp(rawProps, \\"accessibilityHint\\", sourceProps.accessibilityHint, accessibilityHint))
+    accessibilityHint(convertRawProp(rawProps, \\"accessibilityHint\\", sourceProps.accessibilityHint, accessibilityHint)),
+    accessibilityRole(convertRawProp(rawProps, \\"accessibilityRole\\", sourceProps.accessibilityRole, accessibilityRole))
       {}
 
 } // namespace react

packages/react-native-codegen/src/generators/__tests__/__snapshots__/GeneratePropsH-test.js.snap

@@ -452,6 +452,7 @@ class StringPropComponentProps final : public ViewProps {
 #pragma mark - Props
 
   const std::string accessibilityHint{\\"\\"};
+  const std::string accessibilityRole{};
 };
 
 } // namespace react

packages/react-native-codegen/src/generators/__tests__/__snapshots__/GenerateTests-test.js.snap

@@ -457,6 +457,13 @@ TEST(StringPropComponentProps_accessibilityHint, etc) {
   auto const &sourceProps = StringPropComponentProps();
   auto const &rawProps = RawProps(folly::dynamic::object(\\"accessibilityHint\\", \\"foo\\"));
 
+  StringPropComponentProps(sourceProps, rawProps);
+}
+
+TEST(StringPropComponentProps_accessibilityRole, etc) {
+  auto const &sourceProps = StringPropComponentProps();
+  auto const &rawProps = RawProps(folly::dynamic::object(\\"accessibilityRole\\", \\"foo\\"));
+
   StringPropComponentProps(sourceProps, rawProps);
 }",
 }

packages/react-native-codegen/src/generators/__tests__/__snapshots__/GenerateViewConfigJs-test.js.snap

@@ -478,6 +478,7 @@ const StringPropComponentViewConfig = {
 
   validAttributes: {
     accessibilityHint: true,
+    accessibilityRole: true,
   },
 };
 

packages/react-native-codegen/src/parsers/flow/__test_fixtures__/fixtures.js

@@ -137,6 +137,12 @@ type ModuleProps = $ReadOnly<{|
   string_optional_value: ?WithDefault<string, ''>,
   string_optional_both?: ?WithDefault<string, ''>,
 
+  // String props, null default
+  string_null_required: WithDefault<string, null>,
+  string_null_optional_key?: WithDefault<string, null>,
+  string_null_optional_value: ?WithDefault<string, null>,
+  string_null_optional_both?: ?WithDefault<string, null>,
+
   // Float props
   float_required: WithDefault<Float, 1.1>,
   float_optional_key?: WithDefault<Float, 1.1>,

packages/react-native-codegen/src/parsers/flow/__tests__/__snapshots__/parser-test.js.snap

@@ -78,6 +78,38 @@ Object {
                 "type": "StringTypeAnnotation",
               },
             },
+            Object {
+              "name": "string_null_required",
+              "optional": false,
+              "typeAnnotation": Object {
+                "default": null,
+                "type": "StringTypeAnnotation",
+              },
+            },
+            Object {
+              "name": "string_null_optional_key",
+              "optional": true,
+              "typeAnnotation": Object {
+                "default": null,
+                "type": "StringTypeAnnotation",
+              },
+            },
+            Object {
+              "name": "string_null_optional_value",
+              "optional": true,
+              "typeAnnotation": Object {
+                "default": null,
+                "type": "StringTypeAnnotation",
+              },
+            },
+            Object {
+              "name": "string_null_optional_both",
+              "optional": true,
+              "typeAnnotation": Object {
+                "default": null,
+                "type": "StringTypeAnnotation",
+              },
+            },
             Object {
               "name": "float_required",
               "optional": false,

packages/react-native-codegen/src/parsers/flow/props.js

@@ -119,7 +119,7 @@ function getTypeAnnotation(name, typeAnnotation, defaultValue) {
         name: 'PointPrimitive',
       };
     case 'Int32':
-      if (defaultValue !== null) {
+      if (defaultValue != null) {
         return {
           type: 'Int32TypeAnnotation',
           default: (defaultValue: number),
@@ -127,7 +127,7 @@ function getTypeAnnotation(name, typeAnnotation, defaultValue) {
       }
       throw new Error(`A default int is required for "${name}"`);
     case 'Float':
-      if (defaultValue !== null) {
+      if (defaultValue != null) {
         return {
           type: 'FloatTypeAnnotation',
           default: (defaultValue: number),
@@ -135,7 +135,7 @@ function getTypeAnnotation(name, typeAnnotation, defaultValue) {
       }
       throw new Error(`A default float is required for "${name}"`);
     case 'BooleanTypeAnnotation':
-      if (defaultValue !== null) {
+      if (defaultValue != null) {
         return {
           type: 'BooleanTypeAnnotation',
           default: (defaultValue: boolean),
@@ -143,13 +143,13 @@ function getTypeAnnotation(name, typeAnnotation, defaultValue) {
       }
       throw new Error(`A default boolean is required for "${name}"`);
     case 'StringTypeAnnotation':
-      if (defaultValue !== null) {
+      if (typeof defaultValue !== 'undefined') {
         return {
           type: 'StringTypeAnnotation',
-          default: (defaultValue: string),
+          default: (defaultValue: string | null),
         };
       }
-      throw new Error(`A default string is required for "${name}"`);
+      throw new Error(`A default string (or null) is required for "${name}"`);
     case 'UnionTypeAnnotation':
       if (defaultValue !== null) {
         return {
@@ -199,6 +199,18 @@ function buildPropSchema(property): ?PropTypeShape {
     }
     type = typeAnnotation.typeParameters.params[0].type;
     defaultValue = typeAnnotation.typeParameters.params[1].value;
+    const defaultValueType = typeAnnotation.typeParameters.params[1].type;
+
+    if (defaultValueType === 'NullLiteralTypeAnnotation') {
+      if (type !== 'StringTypeAnnotation') {
+        throw new Error(
+          `WithDefault can only provide a 'null' default value for string types (see ${name})`,
+        );
+      }
+
+      defaultValue = null;
+    }
+
     typeAnnotation = typeAnnotation.typeParameters.params[0];
   }