fix(openapi): widen global header type to string when schemas are incompatible

generators/swift/sdk/src/generators/client/util/__test__/snapshots/formatted-endpoint-paths/openapi-accept-header.swift

@@ -0,0 +1,5 @@
+// service_
+"/events"
+"/data"
+"/other"
+"/more"

packages/cli/api-importers/openapi/openapi-ir-to-fern/src/buildGlobalHeaders.ts

@@ -12,8 +12,9 @@ import { getTypeFromTypeReference } from "./utils/getTypeFromTypeReference";
 import { wrapTypeReferenceAsOptional } from "./utils/wrapTypeReferenceAsOptional";
 
 class HeaderWithCount {
-    public readonly schema: RawSchemas.HttpHeaderSchema;
+    public schema: RawSchemas.HttpHeaderSchema;
     public count = 0;
+    private hasIncompatibleSchemas = false;
 
     constructor(schema: RawSchemas.HttpHeaderSchema) {
         this.schema = schema;
@@ -22,6 +23,14 @@ class HeaderWithCount {
     public increment(): void {
         this.count += 1;
     }
+
+    public markIncompatible(): void {
+        this.hasIncompatibleSchemas = true;
+    }
+
+    public isIncompatible(): boolean {
+        return this.hasIncompatibleSchemas;
+    }
 }
 
 /* 75% of endpoints must have header present, for it to be considered a global header*/
@@ -101,6 +110,20 @@ export function buildGlobalHeaders(context: OpenApiIrConverterContext): void {
                     });
                     headerWithCount = new HeaderWithCount(convertedHeader);
                     globalHeaders[header.name] = headerWithCount;
+                } else {
+                    // Check if the current header schema is compatible with the existing one
+                    const currentConvertedHeader = buildHeader({
+                        header,
+                        fileContainingReference: RelativeFilePath.of(ROOT_API_FILENAME),
+                        context,
+                        namespace: undefined
+                    });
+                    const existingType = getTypeFromHttpHeaderSchema(headerWithCount.schema);
+                    const currentType = getTypeFromHttpHeaderSchema(currentConvertedHeader);
+                    if (existingType !== currentType) {
+                        // Schemas are incompatible, widen the type to string
+                        headerWithCount.markIncompatible();
+                    }
                 }
                 headerWithCount.increment();
             }
@@ -115,16 +138,37 @@ export function buildGlobalHeaders(context: OpenApiIrConverterContext): void {
             if (predefinedHeader != null) {
                 continue; // already added
             } else if (isRequired) {
+                // If schemas are incompatible, widen the type to string
+                const schema = header.isIncompatible() ? widenToString(header.schema) : header.schema;
                 context.builder.addGlobalHeader({
                     name: headerName,
-                    schema: header.schema
+                    schema
                 });
             } else if (isOptional) {
+                // If schemas are incompatible, widen the type to string
+                const schema = header.isIncompatible() ? widenToString(header.schema) : header.schema;
                 context.builder.addGlobalHeader({
                     name: headerName,
-                    schema: wrapTypeReferenceAsOptional(header.schema)
+                    schema: wrapTypeReferenceAsOptional(schema)
                 });
             }
         }
     }
 }
+
+function getTypeFromHttpHeaderSchema(schema: RawSchemas.HttpHeaderSchema): string {
+    if (typeof schema === "string") {
+        return schema;
+    }
+    return schema.type;
+}
+
+function widenToString(schema: RawSchemas.HttpHeaderSchema): RawSchemas.HttpHeaderSchema {
+    if (typeof schema === "string") {
+        return "string";
+    }
+    return {
+        ...schema,
+        type: "string"
+    };
+}

packages/cli/fern-definition/ir-to-jsonschema/src/__test__/__snapshots__/openapi-accept-header/type__GetDataResponse.json

@@ -0,0 +1,17 @@
+{
+  "type": "object",
+  "properties": {
+    "id": {
+      "oneOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    }
+  },
+  "additionalProperties": false,
+  "definitions": {}
+}

packages/cli/fern-definition/ir-to-jsonschema/src/__test__/__snapshots__/openapi-accept-header/type__GetMoreResponse.json

@@ -0,0 +1,17 @@
+{
+  "type": "object",
+  "properties": {
+    "value": {
+      "oneOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    }
+  },
+  "additionalProperties": false,
+  "definitions": {}
+}

packages/cli/fern-definition/ir-to-jsonschema/src/__test__/__snapshots__/openapi-accept-header/type__GetOtherResponse.json

@@ -0,0 +1,17 @@
+{
+  "type": "object",
+  "properties": {
+    "name": {
+      "oneOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    }
+  },
+  "additionalProperties": false,
+  "definitions": {}
+}

test-definitions/fern/apis/openapi-accept-header/generators.yml

@@ -0,0 +1,3 @@
+api:
+  specs:
+    - openapi: ./openapi.yml

test-definitions/fern/apis/openapi-accept-header/openapi.yml

@@ -0,0 +1,89 @@
+openapi: 3.0.3
+info:
+  title: Accept Header Test API
+  version: 1.0.0
+  description: Test API for Accept header with text/event-stream default
+paths:
+  /events:
+    get:
+      operationId: getEvents
+      summary: Get events stream
+      description: Returns a stream of events
+      parameters:
+        - $ref: '#/components/parameters/AcceptEventStream'
+      responses:
+        '200':
+          description: Successful response
+          content:
+            text/event-stream:
+              schema:
+                type: string
+  /data:
+    get:
+      operationId: getData
+      summary: Get data as JSON
+      description: Returns data as JSON
+      parameters:
+        - $ref: '#/components/parameters/AcceptJson'
+      responses:
+        '200':
+          description: Successful response
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  id:
+                    type: string
+  /other:
+    get:
+      operationId: getOther
+      summary: Get other data as JSON
+      description: Returns other data as JSON
+      parameters:
+        - $ref: '#/components/parameters/AcceptJson'
+      responses:
+        '200':
+          description: Successful response
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  name:
+                    type: string
+  /more:
+    get:
+      operationId: getMore
+      summary: Get more data as JSON
+      description: Returns more data as JSON
+      parameters:
+        - $ref: '#/components/parameters/AcceptJson'
+      responses:
+        '200':
+          description: Successful response
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  value:
+                    type: string
+components:
+  parameters:
+    AcceptEventStream:
+      name: Accept
+      in: header
+      required: true
+      description: The MIME type of the response body.
+      schema:
+        type: string
+        default: 'text/event-stream'
+    AcceptJson:
+      name: Accept
+      in: header
+      required: true
+      description: The MIME type of the response body.
+      schema:
+        type: string
+        const: 'application/json'