Remove type and optionality constraints from @continuationToken decorator

packages/compiler/src/lib/paging.ts

@@ -26,7 +26,7 @@ import type {
 } from "../core/types.js";
 import { createStateSymbol } from "../lib/utils.js";
 import { DuplicateTracker, useStateSet } from "../utils/index.js";
-import { isNumericType, isStringType } from "./decorators.js";
+import { isNumericType } from "./decorators.js";
 
 export const [
   /**
@@ -109,18 +109,7 @@ export const [
   markContinuationTokenProperty,
   /** {@inheritdoc ContinuationTokenDecorator} */
   continuationTokenDecorator,
-] = createMarkerDecorator<ContinuationTokenDecorator>("continuationToken", (context, target) => {
-  if (!isStringType(context.program, target.type)) {
-    reportDiagnostic(context.program, {
-      code: "decorator-wrong-target",
-      messageId: "withExpected",
-      format: { decorator: "continuationToken", expected: "string", to: getTypeName(target.type) },
-      target: context.decoratorTarget,
-    });
-    return false;
-  }
-  return true;
-});
+] = createMarkerDecorator<ContinuationTokenDecorator>("continuationToken");
 
 export const [
   /**

packages/compiler/test/decorators/paging.test.ts

@@ -213,3 +213,80 @@ describe("collect nested paging properties", () => {
     expect(pathString).toBe("results.items");
   });
 });
+
+describe("@continuationToken supports nullable and optional properties", () => {
+  it("accepts nullable string type (string | null)", async () => {
+    const diagnostics = await runner.diagnose(`
+      @list op list(): {
+        @pageItems items: string[];
+        @continuationToken token: string | null;
+      };
+    `);
+    expectDiagnosticEmpty(diagnostics);
+  });
+
+  it("accepts optional string type", async () => {
+    const diagnostics = await runner.diagnose(`
+      @list op list(): {
+        @pageItems items: string[];
+        @continuationToken token?: string;
+      };
+    `);
+    expectDiagnosticEmpty(diagnostics);
+  });
+
+  it("accepts nullable optional string type", async () => {
+    const diagnostics = await runner.diagnose(`
+      @list op list(): {
+        @pageItems items: string[];
+        @continuationToken token?: string | null;
+      };
+    `);
+    expectDiagnosticEmpty(diagnostics);
+  });
+
+  it("accepts non-string types", async () => {
+    const diagnostics = await runner.diagnose(`
+      @list op list(): {
+        @pageItems items: string[];
+        @continuationToken token: int32;
+      };
+    `);
+    expectDiagnosticEmpty(diagnostics);
+  });
+
+  it("collects nullable continuation token in input", async () => {
+    const { list, token } = (await runner.compile(`
+      @list @test op list(
+        @continuationToken @test token: string | null
+      ): { @pageItems items: string[] };
+    `)) as { list: Operation; token: ModelProperty };
+
+    const paging = ignoreDiagnostics(getPagingOperation(runner.program, list));
+    expect(paging?.input.continuationToken?.property).toBe(token);
+  });
+
+  it("collects nullable continuation token in output", async () => {
+    const { list, token } = (await runner.compile(`
+      @list @test op list(): {
+        @pageItems items: string[];
+        @continuationToken @test token: string | null;
+      };
+    `)) as { list: Operation; token: ModelProperty };
+
+    const paging = ignoreDiagnostics(getPagingOperation(runner.program, list));
+    expect(paging?.output.continuationToken?.property).toBe(token);
+  });
+
+  it("collects optional continuation token", async () => {
+    const { list, token } = (await runner.compile(`
+      @list @test op list(): {
+        @pageItems items: string[];
+        @continuationToken @test token?: string;
+      };
+    `)) as { list: Operation; token: ModelProperty };
+
+    const paging = ignoreDiagnostics(getPagingOperation(runner.program, list));
+    expect(paging?.output.continuationToken?.property).toBe(token);
+  });
+});