Block usage of enum types but allow them as relaxed types (#17)

CHANGELOG.md

@@ -7,6 +7,8 @@ This changelog documents the changes between release versions.
 ## [Unreleased]
 Changes to be included in the next upcoming release
 
+- Improved error messages when unsupported enum types or unions of literal types are found, and allow these types to be used in relaxed types mode ([#17](https://github.com/hasura/ndc-nodejs-lambda/pull/17))
+
 ## [1.1.0] - 2024-02-26
 - Updated to [NDC TypeScript SDK v4.2.0](https://github.com/hasura/ndc-sdk-typescript/releases/tag/v4.2.0) to include OpenTelemetry improvements. Traced spans should now appear in the Hasura Console
 - Custom OpenTelemetry trace spans can now be emitted by creating an OpenTelemetry tracer and using it with `sdk.withActiveSpan` ([#16](https://github.com/hasura/ndc-nodejs-lambda/pull/16))

README.md

@@ -149,6 +149,7 @@ These types are unsupported as function parameter types or return types for func
 * [Function types](https://www.typescriptlang.org/docs/handbook/2/functions.html#function-type-expressions) - function types can't be accepted as arguments or returned as values
 * [`void`](https://www.typescriptlang.org/docs/handbook/2/functions.html#void), [`object`](https://www.typescriptlang.org/docs/handbook/2/functions.html#object), [`unknown`](https://www.typescriptlang.org/docs/handbook/2/functions.html#unknown), [`never`](https://www.typescriptlang.org/docs/handbook/2/functions.html#never), [`any`](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#any) types - to accept and return arbitrary JSON, use `sdk.JSONValue` instead
 * `null` and `undefined` - unless used in a union with a single other type
+* [Enum types](https://www.typescriptlang.org/docs/handbook/enums.html)
 
 ### Relaxed Types
 "Relaxed types" are types that are otherwise unsupported, but instead of being rejected are instead converted into opaque custom scalar types. These scalar types are entirely unvalidated when used as input (ie. the caller of the function can send arbitrary JSON values), making it incumbent on the function itself to ensure the incoming value for that relaxed type actually matches its type. Because relaxed types are represented as custom scalar types, in GraphQL you will be unable to select into the type, if it is an object, and will only be able to select the whole thing.
@@ -161,6 +162,7 @@ The following unsupported types are allowed when using relaxed types, and will b
 * Tuple types
 * Types with index signatures
 * The `any` and `unknown` types
+* Enum types
 
 Here's an example of a function that uses some relaxed types:
 

ndc-lambda-sdk/package.json

@@ -30,7 +30,7 @@
     "url": "git+https://github.com/hasura/ndc-nodejs-lambda.git"
   },
   "dependencies": {
-    "@hasura/ndc-sdk-typescript": "^4.2.0",
+    "@hasura/ndc-sdk-typescript": "^4.2.1",
     "@tsconfig/node18": "^18.2.2",
     "commander": "^11.1.0",
     "cross-spawn": "^7.0.3",

ndc-lambda-sdk/src/inference.ts

@@ -281,6 +281,7 @@ function deriveSchemaTypeForTsType(tsType: ts.Type, typePath: schema.TypePathSeg
     ?? deriveSchemaTypeIfTsArrayType(tsType, typePath, allowRelaxedTypes, context, recursionDepth)
     ?? deriveSchemaTypeIfScalarType(tsType, context)
     ?? deriveSchemaTypeIfNullableType(tsType, typePath, allowRelaxedTypes, context, recursionDepth)
+    ?? deriveSchemaTypeIfEnumType(tsType, typePath, allowRelaxedTypes, context)
     ?? deriveSchemaTypeIfObjectType(tsType, typePath, allowRelaxedTypes, context, recursionDepth)
     ?? rejectIfClassType(tsType, typePath, context) // This needs to be done after scalars, because JSONValue is a class
     ?? deriveSchemaTypeIfTsIndexSignatureType(tsType, typePath, allowRelaxedTypes, context, recursionDepth) // This needs to be done after scalars and classes, etc because some of those types do have index signatures (eg. strings)
@@ -444,6 +445,31 @@ function deriveSchemaTypeIfScalarType(tsType: ts.Type, context: TypeDerivationCo
   }
 }
 
+function deriveSchemaTypeIfEnumType(tsType: ts.Type, typePath: schema.TypePathSegment[], allowRelaxedTypes: boolean, context: TypeDerivationContext): Result<schema.TypeReference, string[]> | undefined {
+  if (tsutils.isUnionType(tsType) && !tsutils.isIntrinsicType(tsType) /* Block booleans */) {
+    const typeName = context.typeChecker.typeToString(tsType);
+
+    // Handles 'enum { First, Second }'
+    if (tsutils.isTypeFlagSet(tsType, ts.TypeFlags.EnumLiteral)) {
+      return deriveRelaxedTypeOrError(typeName, typePath, () => `Enum types are not supported, but one was encountered in ${schema.typePathToString(typePath)} (type: ${typeName})`, allowRelaxedTypes, context);
+    }
+
+    // Handles `"first" | "second"`
+    if (tsType.types.every(unionMemberType => tsutils.isLiteralType(unionMemberType))) {
+      return deriveRelaxedTypeOrError(typeName, typePath, () => `Literal union types are not supported, but one was encountered in ${schema.typePathToString(typePath)} (type: ${typeName})`, allowRelaxedTypes, context);
+    }
+  }
+  // Handles computed single member enum types: 'enum { OneThing = "test".length }'
+  else if (tsutils.isEnumType(tsType) && tsutils.isSymbolFlagSet(tsType.symbol, ts.SymbolFlags.EnumMember)) {
+    const typeName = context.typeChecker.typeToString(tsType);
+    return deriveRelaxedTypeOrError(typeName, typePath, () => `Enum types are not supported, but one was encountered in ${schema.typePathToString(typePath)} (type: ${typeName})`, allowRelaxedTypes, context);
+  }
+
+  // Note that single member enum types: 'enum { OneThing }' are simplified by the type system
+  // down to literal types (since they can only be a single thing) and are therefore supported via support
+  // for literal types in scalars
+}
+
 function isDateType(tsType: ts.Type): boolean {
   const symbol = tsType.getSymbol()
   if (symbol === undefined) return false;
@@ -464,12 +490,9 @@ function isMapType(tsType: ts.Type): tsType is ts.TypeReference {
 function isBooleanUnionType(tsType: ts.Type): boolean {
   if (!tsutils.isUnionType(tsType)) return false;
 
-  return tsType.types.length === 2 && unionTypeContainsBothBooleanLiterals(tsType);
-}
-
-function unionTypeContainsBothBooleanLiterals(tsUnionType: ts.UnionType): boolean {
-  return tsUnionType.types.find(tsType => tsutils.isBooleanLiteralType(tsType) && tsType.intrinsicName === "true") !== undefined
-    && tsUnionType.types.find(tsType => tsutils.isBooleanLiteralType(tsType) && tsType.intrinsicName === "false") !== undefined;
+  return tsType.types.length === 2
+    && tsType.types.find(type => tsutils.isBooleanLiteralType(type) && type.intrinsicName === "true") !== undefined
+    && tsType.types.find(type => tsutils.isBooleanLiteralType(type) && type.intrinsicName === "false") !== undefined;
 }
 
 function isJSONValueType(tsType: ts.Type, ndcLambdaSdkModule: ts.ResolvedModuleFull): boolean {
@@ -581,21 +604,10 @@ function unwrapNullableType(tsType: ts.Type, typeChecker: ts.TypeChecker): [ts.T
           : null
         );
 
-  const typesWithoutNullAndUndefined = tsType.types
-    .filter(t => !tsutils.isIntrinsicNullType(t) && !tsutils.isIntrinsicUndefinedType(t));
 
-  // The case where one type is unioned with either or both of null and undefined
-  if (typesWithoutNullAndUndefined.length === 1 && nullOrUndefinability) {
-    return [typesWithoutNullAndUndefined[0]!, nullOrUndefinability];
-  }
-  // The weird edge case where null or undefined is unioned with both 'true' and 'false'
-  // We simplify this to being unioned with 'boolean' instead
-  else if (nullOrUndefinability && typesWithoutNullAndUndefined.length === 2 && unionTypeContainsBothBooleanLiterals(tsType)) {
-    return [typeChecker.getBooleanType(), nullOrUndefinability];
-  }
-  else {
-    return null;
-  }
+  return nullOrUndefinability
+    ? [typeChecker.getNonNullableType(tsType), nullOrUndefinability]
+    : null;
 }
 
 type PropertyTypeInfo = {

ndc-lambda-sdk/test/inference/basic-inference/basic-inference.test.ts

@@ -925,7 +925,17 @@ describe("basic inference", function() {
                   name: BuiltInScalarTypeName.Float,
                   literalValue: 0,
                 }
-              }
+              },
+              {
+                propertyName: "singleItemEnum",
+                description: null,
+                type: {
+                  type: "named",
+                  kind: "scalar",
+                  name: BuiltInScalarTypeName.String,
+                  literalValue: "SingleItem",
+                }
+              },
             ],
             isRelaxedType: false,
           }

ndc-lambda-sdk/test/inference/basic-inference/literal-types.ts

@@ -5,14 +5,22 @@ type LiteralProps = {
   literalBigInt: -123n,
   literalStringEnum: StringEnum.EnumItem
   literalNumericEnum: NumericEnum.EnumItem
+  singleItemEnum: SingleItemEnum
 }
 
 enum StringEnum {
-  EnumItem = "EnumItem"
+  EnumItem = "EnumItem",
+  SecondEnumItem = "SecondEnumItem"
 }
 
 enum NumericEnum {
-  EnumItem
+  EnumItem,
+  SecondEnumItem
+}
+
+// Single item enums are simplified by the compiler to a literal type
+enum SingleItemEnum {
+  SingleItem = "SingleItem"
 }
 
 export function literalTypes(): LiteralProps {
@@ -23,5 +31,6 @@ export function literalTypes(): LiteralProps {
     literalBigInt: -123n,
     literalStringEnum: StringEnum.EnumItem,
     literalNumericEnum: NumericEnum.EnumItem,
+    singleItemEnum: SingleItemEnum.SingleItem
   };
 }

ndc-lambda-sdk/test/inference/relaxed-types/enum-types-invalid.ts

@@ -0,0 +1,12 @@
+type StringLiteralEnum = "1st" | "2nd" | Promise<"3rd">
+
+/**
+ * @readonly
+ * @allowrelaxedtypes
+ */
+export function enumTypesFunction(
+  stringLiteralEnum: StringLiteralEnum,
+  inlineStringLiteralEnum: "1st" | "2nd" | void,
+): string {
+  return ""
+}

ndc-lambda-sdk/test/inference/relaxed-types/enum-types-valid.ts

@@ -0,0 +1,70 @@
+enum StringEnum {
+  First = "First",
+  Second = "Second"
+}
+
+enum NumberEnum {
+  First = 1,
+  Second = 2
+}
+
+enum MixedEnum {
+  Dog = "Dog",
+  Cat = "Cat",
+  Other = 1234,
+}
+
+const enum ConstEnum {
+  First = "first",
+  Second = "second",
+}
+
+enum ComputedEnum {
+  Gross = "Gross".length,
+  Foul = "Foul".length
+}
+
+enum ComputedSingleItemEnum {
+  Single = "Single".length
+}
+
+type StringLiteralEnum = "1st" | "2nd"
+
+type NumberLiteralEnum = 0 | 1 | 2
+
+type MixedLiteralEnum = true | false | 0 | 1 | "1st" | "2nd"
+
+const ConstObjEnumVal = {
+  Plant: "plant",
+  Animal: "animal"
+} as const;
+
+type ConstObjEnum = typeof ConstObjEnumVal[keyof typeof ConstObjEnumVal]
+
+/**
+ * @readonly
+ * @allowrelaxedtypes
+ */
+export function enumTypesFunction(
+  stringEnum: StringEnum,
+  numberEnum: NumberEnum,
+  mixedEnum: MixedEnum,
+  constEnum: ConstEnum,
+  computedEnum: ComputedEnum,
+  computedSingleItemEnum: ComputedSingleItemEnum,
+  stringLiteralEnum: StringLiteralEnum,
+  stringLiteralEnumMaybe: StringLiteralEnum | undefined,
+  inlineStringLiteralEnum: "1st" | "2nd",
+  inlineStringLiteralEnumMaybe: "1st" | "2nd" | null,
+  numberLiteralEnum: NumberLiteralEnum,
+  numberLiteralEnumMaybe: NumberLiteralEnum | null,
+  inlineNumberLiteralEnum: 0 | 1 | 2,
+  inlineNumberLiteralEnumMaybe: 0 | 1 | 2 | undefined,
+  mixedLiteralEnum: MixedLiteralEnum,
+  mixedLiteralEnumMaybe: MixedLiteralEnum | undefined | null,
+  inlineMixedLiteralEnum: true | 1 | "first",
+  inlineMixedLiteralEnumMaybe: true | 1 | "first" | undefined | null,
+  constObjEnum: ConstObjEnum,
+): string {
+  return ""
+}