(feat, cli): introduce x-fern-undiscriminated extension (#4048)

fern-api · Jul 12, 2024 · 5a7f726 · 5a7f726
1 parent 8301e1b
commit 5a7f726
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Showing 2 changed files with 25 additions and 12 deletions.
diff --git a/packages/cli/openapi-parser/src/openapi/v3/extensions/fernExtensions.ts b/packages/cli/openapi-parser/src/openapi/v3/extensions/fernExtensions.ts
@@ -383,7 +383,19 @@ export const FernOpenAPIExtension = {
     /**
      * Allows a user to configure the property name for the schema.
      */
-    FERN_PROPERTY_NAME: "x-fern-property-name"
+    FERN_PROPERTY_NAME: "x-fern-property-name",
+
+    /**
+     * Allows a user to configure that a union wiht a discriminant should
+     * be undiscriminated. 
+     * 
+     * Shape:
+     *   x-fern-undiscriminated: true
+     *   oneOf: 
+     *    - $ref: components/schemas/Triangle
+     *    - $ref: components/schemas/Square
+     */
+    IS_UNDISCRIMINATED: "x-fern-undiscriminated"
 } as const;
 
 export type FernOpenAPIExtension = Values<typeof FernOpenAPIExtension>;
diff --git a/packages/cli/openapi-parser/src/schema/convertSchemas.ts b/packages/cli/openapi-parser/src/schema/convertSchemas.ts
@@ -451,33 +451,34 @@ export function convertSchemaObject(
 
     // handle oneOf
     if (schema.oneOf != null && schema.oneOf.length > 0) {
+        const isUndiscriminated = getExtension(schema, FernOpenAPIExtension.IS_UNDISCRIMINATED);
         if (
             schema.discriminator != null &&
             schema.discriminator.mapping != null &&
             Object.keys(schema.discriminator.mapping).length > 0
         ) {
-            if (!context.options.discriminatedUnionV2) {
-                return convertDiscriminatedOneOf({
+            if (context.options.discriminatedUnionV2 || isUndiscriminated) {
+                return convertUndiscriminatedOneOfWithDiscriminant({
                     nameOverride,
                     generatedName,
-                    breadcrumbs,
                     description,
-                    discriminator: schema.discriminator,
-                    properties: schema.properties ?? {},
-                    required: schema.required,
                     wrapAsNullable,
                     context,
-                    groupName
+                    groupName,
+                    discriminator: schema.discriminator
                 });
             } else {
-                return convertUndiscriminatedOneOfWithDiscriminant({
+                return convertDiscriminatedOneOf({
                     nameOverride,
                     generatedName,
+                    breadcrumbs,
                     description,
+                    discriminator: schema.discriminator,
+                    properties: schema.properties ?? {},
+                    required: schema.required,
                     wrapAsNullable,
                     context,
-                    groupName,
-                    discriminator: schema.discriminator
+                    groupName
                 });
             }
         } else if (schema.oneOf.length === 1 && schema.oneOf[0] != null) {
@@ -516,7 +517,7 @@ export function convertSchemaObject(
             }
 
             const maybeDiscriminant = getDiscriminant({ schemas: schema.oneOf, context });
-            if (maybeDiscriminant != null && !context.options.discriminatedUnionV2) {
+            if (maybeDiscriminant != null && !context.options.discriminatedUnionV2 && !isUndiscriminated) {
                 return convertDiscriminatedOneOfWithVariants({
                     nameOverride,
                     generatedName,