fix: adds missing events import and fully qualifies name

.chronus/changes/fix-events-import-2025-11-23-10-21-25.md

@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/openapi3"
+---
+
+import tool - missing imports for SSE events

.chronus/changes/fix-events-import-2025-11-24-9-51-57.md

@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/openapi3"
+---
+
+import tool - escape SSE event union identifiers when required

packages/openapi3/src/cli/actions/convert/generators/generate-main.ts

@@ -13,7 +13,7 @@ export function generateMain(program: TypeSpecProgram, context: Context): string
   import "@typespec/events";`
     : "";
 
-  const sseUsings = context.isSSEUsed() ? "\n  using SSE;" : "";
+  const sseUsings = context.isSSEUsed() ? "\n  using SSE;\n  using Events;" : "";
 
   return `
   import "@typespec/http";

packages/openapi3/src/cli/actions/convert/generators/generate-model.ts

@@ -214,7 +214,7 @@ function generateSSEEventVariants(
         decorators += `\n  @extension("${SSE_TERMINAL_EVENT_EXTENSION}", true)`;
       }
 
-      return `${decorators}\n  ${eventName}: ${dataType},`;
+      return `${decorators}\n  ${printIdentifier(eventName)}: ${dataType},`;
     } catch (error) {
       // If any error occurs, fall back to regular generation
       return (

packages/openapi3/src/cli/actions/convert/transforms/transform-component-schemas.ts

@@ -148,7 +148,7 @@ export function transformComponentSchemas(context: Context, models: TypeSpecData
     if (context.isSSEEventSchema(schemaRef)) {
       // Remove @oneOf decorator if present and add @events
       decorators = decorators.filter((d) => d.name !== "oneOf");
-      decorators.push({ name: "events", args: [] });
+      decorators.push({ name: "TypeSpec.Events.events", args: [] });
     }
 
     const union: TypeSpecUnion = {

packages/openapi3/test/sse.test.ts

@@ -201,6 +201,45 @@ describe("openapi3: SSE (Server-Sent Events)", () => {
       deepStrictEqual(terminalVariant.properties.data.contentMediaType, "text/plain");
       deepStrictEqual(terminalVariant["x-ms-sse-terminal-event"], true);
     });
+
+    it("emits itemSchema with terminal event marked by extension with a discriminated member", async () => {
+      const openApi = await openApiFor(
+        `
+        model UserConnect {
+          username: string;
+        }
+
+        model UserMessage {
+          text: string;
+        }
+
+        @events
+        union ChannelEvents {
+          userconnect: UserConnect,
+          @terminalEvent
+          @extension("x-ms-sse-terminal-event", true)
+          usermessage: UserMessage,
+        }
+
+        @route("/channel")
+        @get op subscribe(): SSEStream<ChannelEvents>;
+        `,
+      );
+
+      ok(openApi.paths["/channel"], "expected /channel path");
+      const response = openApi.paths["/channel"].get.responses["200"];
+      const eventStreamContent = response.content["text/event-stream"];
+      ok(eventStreamContent.itemSchema, "expected itemSchema for SSE");
+
+      // Check oneOf includes all three events
+      ok(eventStreamContent.itemSchema.oneOf, "expected oneOf");
+      deepStrictEqual(eventStreamContent.itemSchema.oneOf.length, 2);
+
+      // Check terminal event
+      const terminalVariant = eventStreamContent.itemSchema.oneOf[1];
+      ok(terminalVariant, "expected terminal event variant");
+      deepStrictEqual(terminalVariant["x-ms-sse-terminal-event"], true);
+    });
   });
 
   describe("SSE stream with custom content types", () => {

packages/openapi3/test/tsp-openapi3/output/sse-import-scenarios-3-1/main.tsp

@@ -52,11 +52,11 @@ union ChannelEventWithCustomContentType {
   },
 }
 
-@route("/channel/no-terminal") @get op subscribeToChannelNoTerminal(): {
+@route("/channel/no-terminal") @get op subscribeToChannelNoTerminalGet(): {
   @header contentType: "text/event-stream";
 };
 
-@route("/channel/no-terminal-post") @post op subscribeToChannelNoTerminal(
+@route("/channel/no-terminal-post") @post op subscribeToChannelNoTerminalPost(
   /** Request body for subscribing to a channel without terminal event. */
   @body body: {
     channelId?: string;

packages/openapi3/test/tsp-openapi3/output/sse-import-scenarios/main.tsp

@@ -8,6 +8,7 @@ import "@typespec/events";
 using Http;
 using OpenAPI;
 using SSE;
+using Events;
 
 @service(#{ title: "SSE Import Scenarios" })
 @info(#{ version: "0.0.0" })
@@ -21,13 +22,13 @@ model UserMessage {
   text: string;
 }
 
-@events
+@TypeSpec.Events.events
 union ChannelEventsNoTerminal {
   userconnect: UserConnect,
   usermessage: UserMessage,
 }
 
-@events
+@TypeSpec.Events.events
 union ChannelEventsWithTerminal {
   userconnect: UserConnect,
   usermessage: UserMessage,
@@ -38,16 +39,25 @@ union ChannelEventsWithTerminal {
   "[done]",
 }
 
-@events
+@TypeSpec.Events.events
+union ChannelEventsWithDiscriminatedTerminal {
+  userconnect: UserConnect,
+
+  @TypeSpec.SSE.terminalEvent
+  @extension("x-ms-sse-terminal-event", true)
+  usermessage: UserMessage,
+}
+
+@TypeSpec.Events.events
 union ChannelEventWithCustomContentType {
   @TypeSpec.Events.contentType("application/octet-stream")
   binary: Base64,
 }
 
-@route("/channel/no-terminal") @get op subscribeToChannelNoTerminal(
+@route("/channel/no-terminal") @get op subscribeToChannelNoTerminalGet(
 ): SSEStream<ChannelEventsNoTerminal>;
 
-@route("/channel/no-terminal-post") @post op subscribeToChannelNoTerminal(
+@route("/channel/no-terminal-post") @post op subscribeToChannelNoTerminalPost(
   /** Request body for subscribing to a channel without terminal event. */
   @body body: {
     channelId?: string;
@@ -57,5 +67,8 @@ union ChannelEventWithCustomContentType {
 @route("/channel/with-terminal") @get op subscribeToChannelWithTerminal(
 ): SSEStream<ChannelEventsWithTerminal>;
 
+@route("/channel/with-discriminated-terminal") @get op subscribeToChannelWithDiscriminatedTerminal(
+): SSEStream<ChannelEventsWithDiscriminatedTerminal>;
+
 @route("/data/custom-content-type") @get op subscribeToDataStream(
 ): SSEStream<ChannelEventWithCustomContentType>;

packages/openapi3/test/tsp-openapi3/specs/sse-import-scenarios-3-1/service.yml

@@ -93,7 +93,7 @@ components:
 paths:
   /channel/no-terminal:
     get:
-      operationId: subscribeToChannelNoTerminal
+      operationId: subscribeToChannelNoTerminalGet
       responses:
         "200":
           description: A request body to add a stream of typed data.
@@ -103,7 +103,7 @@ paths:
                 $ref: "#/components/schemas/ChannelEventsNoTerminal"
   /channel/no-terminal-post:
     post:
-      operationId: subscribeToChannelNoTerminal
+      operationId: subscribeToChannelNoTerminalPost
       requestBody:
         description: Request body for subscribing to a channel without terminal event.
         required: true

packages/openapi3/test/tsp-openapi3/specs/sse-import-scenarios/service.yml

@@ -69,6 +69,31 @@ components:
               contentMediaType: application/json
               contentSchema:
                 $ref: "#/components/schemas/UserMessage"
+    ChannelEventsWithDiscriminatedTerminal:
+      type: object
+      properties:
+        event:
+          type: string
+        data:
+          type: string
+      required: [event]
+      # Define event types and specific schemas for the corresponding data
+      oneOf:
+        - properties:
+            event:
+              const: userconnect
+            data:
+              contentMediaType: application/json
+              contentSchema:
+                $ref: "#/components/schemas/UserConnect"
+        - properties:
+            event:
+              const: usermessage
+            data:
+              contentMediaType: application/json
+              contentSchema:
+                $ref: "#/components/schemas/UserMessage"
+          x-ms-sse-terminal-event: true
     ChannelEventWithCustomContentType:
       type: object
       properties:
@@ -93,7 +118,7 @@ components:
 paths:
   /channel/no-terminal:
     get:
-      operationId: subscribeToChannelNoTerminal
+      operationId: subscribeToChannelNoTerminalGet
       responses:
         "200":
           description: A request body to add a stream of typed data.
@@ -103,7 +128,7 @@ paths:
                 $ref: "#/components/schemas/ChannelEventsNoTerminal"
   /channel/no-terminal-post:
     post:
-      operationId: subscribeToChannelNoTerminal
+      operationId: subscribeToChannelNoTerminalPost
       requestBody:
         description: Request body for subscribing to a channel without terminal event.
         required: true
@@ -131,6 +156,16 @@ paths:
             text/event-stream:
               itemSchema:
                 $ref: "#/components/schemas/ChannelEventsWithTerminal"
+  /channel/with-discriminated-terminal:
+    get:
+      operationId: subscribeToChannelWithDiscriminatedTerminal
+      responses:
+        "200":
+          description: A request body to add a stream of typed data.
+          content:
+            text/event-stream:
+              itemSchema:
+                $ref: "#/components/schemas/ChannelEventsWithDiscriminatedTerminal"
   /data/custom-content-type:
     get:
       operationId: subscribeToDataStream