From 0b9c7b8cf705310703d90bfe602be404d0590750 Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Thu, 6 Apr 2023 15:41:12 +0300
Subject: [PATCH 01/13] Add `@sharedRoute` decorator and decouple it from
 `@route`

---
 .../split-shared-route_2023-04-06-12-41.json  | 10 ++++
 packages/http/src/decorators.ts               | 14 ++++-
 packages/http/src/route.ts                    | 25 ++++++--
 packages/http/test/routes.test.ts             | 57 ++++++++++++++++++-
 4 files changed, 98 insertions(+), 8 deletions(-)
 create mode 100644 common/changes/@typespec/http/split-shared-route_2023-04-06-12-41.json

diff --git a/common/changes/@typespec/http/split-shared-route_2023-04-06-12-41.json b/common/changes/@typespec/http/split-shared-route_2023-04-06-12-41.json
new file mode 100644
index 00000000000..aab447a5c81
--- /dev/null
+++ b/common/changes/@typespec/http/split-shared-route_2023-04-06-12-41.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@typespec/http",
+      "comment": "Add `@sharedRoute` decorator for marking operations as sharing a route with other operations",
+      "type": "none"
+    }
+  ],
+  "packageName": "@typespec/http"
+}
\ No newline at end of file
diff --git a/packages/http/src/decorators.ts b/packages/http/src/decorators.ts
index c7e5506ceaf..d4ec12fc833 100644
--- a/packages/http/src/decorators.ts
+++ b/packages/http/src/decorators.ts
@@ -19,7 +19,7 @@ import {
   validateDecoratorUniqueOnNode,
 } from "@typespec/compiler";
 import { createDiagnostic, createStateSymbol, reportDiagnostic } from "./lib.js";
-import { setRoute } from "./route.js";
+import { setRoute, setSharedRoute } from "./route.js";
 import {
   AuthenticationOption,
   HeaderFieldOptions,
@@ -596,6 +596,18 @@ export function $route(context: DecoratorContext, entity: Type, path: string, pa
   });
 }
 
+/**
+ * `@sharedRoute` marks the operation as sharing a route path with other operations.
+ *
+ * When an operation is marked with `@sharedRoute`, it enables other operations to share the same
+ * route path as long as those operations are also marked with `@sharedRoute`.
+ *
+ * `@sharedRoute` can only be applied directly to operations.
+ */
+export function $sharedRoute(context: DecoratorContext, entity: Operation) {
+  setSharedRoute(context.program, entity);
+}
+
 const includeInapplicableMetadataInPayloadKey = createStateSymbol(
   "includeInapplicableMetadataInPayload"
 );
diff --git a/packages/http/src/route.ts b/packages/http/src/route.ts
index a226dccf98b..d8b9d9d77a8 100644
--- a/packages/http/src/route.ts
+++ b/packages/http/src/route.ts
@@ -216,8 +216,8 @@ export function setRoute(context: DecoratorContext, entity: Type, details: Route
   const state = context.program.stateMap(routesKey);
 
   if (state.has(entity) && entity.kind === "Namespace") {
-    const existingValue: RoutePath = state.get(entity);
-    if (existingValue.path !== details.path) {
+    const existingPath: string | undefined = state.get(entity);
+    if (existingPath !== details.path) {
       reportDiagnostic(context.program, {
         code: "duplicate-route-decorator",
         messageId: "namespace",
@@ -225,19 +225,34 @@ export function setRoute(context: DecoratorContext, entity: Type, details: Route
       });
     }
   } else {
-    state.set(entity, details);
+    state.set(entity, details.path);
+    if (entity.kind === "Operation" && details.shared) {
+      setSharedRoute(context.program, entity as Operation);
+    }
   }
 }
 
+const sharedRoutesKey = createStateSymbol("sharedRoutes");
+
+export function setSharedRoute(program: Program, operation: Operation) {
+  program.stateMap(sharedRoutesKey).set(operation, true);
+}
+
 export function isSharedRoute(program: Program, operation: Operation): boolean {
-  return program.stateMap(routesKey).get(operation)?.shared;
+  return program.stateMap(sharedRoutesKey).get(operation) === true;
 }
 
 export function getRoutePath(
   program: Program,
   entity: Namespace | Interface | Operation
 ): RoutePath | undefined {
-  return program.stateMap(routesKey).get(entity);
+  const path = program.stateMap(routesKey).get(entity);
+  return path
+    ? {
+        path,
+        shared: entity.kind === "Operation" && isSharedRoute(program, entity as Operation),
+      }
+    : undefined;
 }
 
 const routeOptionsKey = createStateSymbol("routeOptions");
diff --git a/packages/http/test/routes.test.ts b/packages/http/test/routes.test.ts
index 35c556eee02..3f4e04d230d 100644
--- a/packages/http/test/routes.test.ts
+++ b/packages/http/test/routes.test.ts
@@ -1,7 +1,13 @@
+import { Operation } from "@typespec/compiler";
 import { expectDiagnosticEmpty, expectDiagnostics } from "@typespec/compiler/testing";
 import { deepStrictEqual, strictEqual } from "assert";
-import { HttpOperation } from "../src/index.js";
-import { compileOperations, getOperations, getRoutesFor } from "./test-host.js";
+import { getRoutePath, HttpOperation } from "../src/index.js";
+import {
+  compileOperations,
+  createHttpTestRunner,
+  getOperations,
+  getRoutesFor,
+} from "./test-host.js";
 
 describe("http: routes", () => {
   // Describe how routes should be included.
@@ -545,4 +551,51 @@ describe("http: routes", () => {
       { verb: "put", path: "/things/{thingId}", params: ["thingId"] },
     ]);
   });
+
+  describe("shared routes", () => {
+    it("@sharedRoute decorator makes routes shared", async () => {
+      const runner = await createHttpTestRunner();
+      const { get1, get2 } = (await runner.compile(`
+        @route("/test")
+        namespace Foo {
+          @test
+          @sharedRoute
+          @route("/get1")
+          op get1(): string;
+        }
+
+        @route("/test")
+        namespace Foo {
+          @test
+          @route("/get2")
+          op get2(): string;
+        }
+      `)) as { get1: Operation; get2: Operation };
+
+      strictEqual(getRoutePath(runner.program, get1)?.shared, true);
+      strictEqual(getRoutePath(runner.program, get2)?.shared, false);
+    });
+
+    it("legacy `shared: true parameter` still works", async () => {
+      const runner = await createHttpTestRunner();
+      const { get1, get2 } = (await runner.compile(`
+        @route("/test")
+        namespace Foo {
+          @test
+          @route("/get1", { shared: true })
+          op get1(): string;
+        }
+
+        @route("/test")
+        namespace Foo {
+          @test
+          @route("/get2", { shared: false })
+          op get2(): string;
+        }
+      `)) as { get1: Operation; get2: Operation };
+
+      strictEqual(getRoutePath(runner.program, get1)?.shared, true);
+      strictEqual(getRoutePath(runner.program, get2)?.shared, false);
+    });
+  });
 });

From ebc926cb970801d7d6579862eac909a13a2e1b85 Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Fri, 7 Apr 2023 17:43:24 +0300
Subject: [PATCH 02/13] Add decorator definitions for @route and @sharedRoute

---
 packages/http/lib/http-decorators.tsp | 32 +++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/packages/http/lib/http-decorators.tsp b/packages/http/lib/http-decorators.tsp
index 37f8a68c638..32243be8608 100644
--- a/packages/http/lib/http-decorators.tsp
+++ b/packages/http/lib/http-decorators.tsp
@@ -204,3 +204,35 @@ extern dec useAuth(target: Namespace, auth: object | Union | object[]);
  * Specify if inapplicable metadata should be included in the payload for the given entity.
  */
 extern dec includeInapplicableMetadataInPayload(target: unknown, value: boolean);
+
+/**
+ * `@route` defines the relative route URI for the target operation
+ *
+ * The first argument should be a URI fragment that may contain one or more path parameter fields.
+ * If the namespace or interface that contains the operation is also marked with a `@route` decorator,
+ * it will be used as a prefix to the route URI of the operation.
+ *
+ * `@route` can only be applied to operations, namespaces, and interfaces.
+ *
+ * ```typespec
+ * @route("/widgets")
+ * op getWidget(@path id: string): Widget;
+ * ```
+ */
+extern dec route(target: Namespace | Interface | Operation, path: string, options?: object);
+
+/**
+ * `@sharedRoute` marks the operation as sharing a route path with other operations.
+ *
+ * When an operation is marked with `@sharedRoute`, it enables other operations to share the same
+ * route path as long as those operations are also marked with `@sharedRoute`.
+ *
+ * `@sharedRoute` can only be applied directly to operations.
+ *
+ * ```typespec
+ * @sharedRoute
+ * @route("/widgets")
+ * op getWidget(@path id: string): Widget;
+ * ```
+ */
+extern dec sharedRoute(target: Operation);

From aa639c6d0f5509f483149a25fbbf69ebfcd4bebd Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Fri, 7 Apr 2023 17:48:16 +0300
Subject: [PATCH 03/13] Add autoRoute shared route tests

---
 .../split-shared-route_2023-04-07-14-49.json  | 10 ++++++++
 packages/rest/test/routes.test.ts             | 25 ++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 common/changes/@typespec/rest/split-shared-route_2023-04-07-14-49.json

diff --git a/common/changes/@typespec/rest/split-shared-route_2023-04-07-14-49.json b/common/changes/@typespec/rest/split-shared-route_2023-04-07-14-49.json
new file mode 100644
index 00000000000..64135d54e31
--- /dev/null
+++ b/common/changes/@typespec/rest/split-shared-route_2023-04-07-14-49.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@typespec/rest",
+      "comment": "",
+      "type": "none"
+    }
+  ],
+  "packageName": "@typespec/rest"
+}
\ No newline at end of file
diff --git a/packages/rest/test/routes.test.ts b/packages/rest/test/routes.test.ts
index 459aef33019..303f5cd7b75 100644
--- a/packages/rest/test/routes.test.ts
+++ b/packages/rest/test/routes.test.ts
@@ -1,7 +1,13 @@
 import { ModelProperty, Operation } from "@typespec/compiler";
 import { expectDiagnostics } from "@typespec/compiler/testing";
+import { isSharedRoute } from "@typespec/http";
 import { deepStrictEqual, strictEqual } from "assert";
-import { compileOperations, getOperations, getRoutesFor } from "./test-host.js";
+import {
+  compileOperations,
+  createRestTestRunner,
+  getOperations,
+  getRoutesFor,
+} from "./test-host.js";
 
 describe("rest: routes", () => {
   it("always produces a route starting with /", async () => {
@@ -441,4 +447,21 @@ describe("rest: routes", () => {
       { verb: "put", path: "/things/{thingId}", params: ["thingId"] },
     ]);
   });
+
+  it("@autoRoute operations can also be shared routes", async () => {
+    const runner = await createRestTestRunner();
+    const { get1, get2 } = (await runner.compile(`
+      @test
+      @autoRoute
+      @sharedRoute
+      op get1(@path name: string): string;
+
+      @test
+      @autoRoute
+      op get2(@path name: string): string;
+    `)) as { get1: Operation; get2: Operation };
+
+    strictEqual(isSharedRoute(runner.program, get1), true);
+    strictEqual(isSharedRoute(runner.program, get2), false);
+  });
 });

From d2564b39ab365dfa791326f34fd13566a17c7ff8 Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Fri, 7 Apr 2023 18:35:48 +0300
Subject: [PATCH 04/13] Update generated documentation

---
 .../http/reference/decorators.md              | 57 +++++++++++++++++++
 docs/standard-library/http/reference/index.md |  2 +
 2 files changed, 59 insertions(+)

diff --git a/docs/standard-library/http/reference/decorators.md b/docs/standard-library/http/reference/decorators.md
index 53ffef9c121..0656e5fa854 100644
--- a/docs/standard-library/http/reference/decorators.md
+++ b/docs/standard-library/http/reference/decorators.md
@@ -295,3 +295,60 @@ dec TypeSpec.Http.includeInapplicableMetadataInPayload(target: unknown, value: b
 | Name  | Type             | Description |
 | ----- | ---------------- | ----------- |
 | value | `scalar boolean` |             |
+
+### `@route` {#@TypeSpec.Http.route}
+
+`@route` defines the relative route URI for the target operation
+
+The first argument should be a URI fragment that may contain one or more path parameter fields.
+If the namespace or interface that contains the operation is also marked with a `@route` decorator,
+it will be used as a prefix to the route URI of the operation.
+
+`@route` can only be applied to operations, namespaces, and interfaces.
+
+```typespec
+@route("/widgets")
+op getWidget(@path id: string): Widget;
+```
+
+```typespec
+dec TypeSpec.Http.route(target: Namespace | Interface | Operation, path: string, options?: object)
+```
+
+#### Target
+
+`union Namespace | Interface | Operation`
+
+#### Parameters
+
+| Name    | Type            | Description |
+| ------- | --------------- | ----------- |
+| path    | `scalar string` |             |
+| options | `model object`  |             |
+
+### `@sharedRoute` {#@TypeSpec.Http.sharedRoute}
+
+`@sharedRoute` marks the operation as sharing a route path with other operations.
+
+When an operation is marked with `@sharedRoute`, it enables other operations to share the same
+route path as long as those operations are also marked with `@sharedRoute`.
+
+`@sharedRoute` can only be applied directly to operations.
+
+```typespec
+@sharedRoute
+@route("/widgets")
+op getWidget(@path id: string): Widget;
+```
+
+```typespec
+dec TypeSpec.Http.sharedRoute(target: Operation)
+```
+
+#### Target
+
+`Operation`
+
+#### Parameters
+
+None
diff --git a/docs/standard-library/http/reference/index.md b/docs/standard-library/http/reference/index.md
index 7c0c6d32acc..7ac4a1f2e1f 100644
--- a/docs/standard-library/http/reference/index.md
+++ b/docs/standard-library/http/reference/index.md
@@ -20,7 +20,9 @@ toc_max_heading_level: 3
 - [`@post`](./decorators.md#@TypeSpec.Http.post)
 - [`@put`](./decorators.md#@TypeSpec.Http.put)
 - [`@query`](./decorators.md#@TypeSpec.Http.query)
+- [`@route`](./decorators.md#@TypeSpec.Http.route)
 - [`@server`](./decorators.md#@TypeSpec.Http.server)
+- [`@sharedRoute`](./decorators.md#@TypeSpec.Http.sharedRoute)
 - [`@statusCode`](./decorators.md#@TypeSpec.Http.statusCode)
 - [`@useAuth`](./decorators.md#@TypeSpec.Http.useAuth)
 

From 311fabbb03e215040be0d073616448f97a05a09a Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Tue, 18 Apr 2023 09:54:59 +0300
Subject: [PATCH 05/13] Deprecate `shared` option for `@route` parameter

---
 packages/http/src/decorators.ts            | 35 +++++++++++-----------
 packages/http/test/http-decorators.test.ts | 24 ++++++++++++---
 packages/http/test/routes.test.ts          |  2 ++
 packages/rest/test/routes.test.ts          |  4 +--
 4 files changed, 41 insertions(+), 24 deletions(-)

diff --git a/packages/http/src/decorators.ts b/packages/http/src/decorators.ts
index cbea500f12d..b6754ee0184 100644
--- a/packages/http/src/decorators.ts
+++ b/packages/http/src/decorators.ts
@@ -3,6 +3,7 @@ import {
   DecoratorContext,
   Diagnostic,
   DiagnosticTarget,
+  reportDeprecated,
   getDoc,
   isArrayModelType,
   Model,
@@ -559,23 +560,6 @@ export function getAuthentication(
   return program.stateMap(authenticationKey).get(namespace);
 }
 
-function extractSharedValue(context: DecoratorContext, parameters?: Model): boolean {
-  const sharedType = parameters?.properties.get("shared")?.type;
-  if (sharedType === undefined) {
-    return false;
-  }
-  switch (sharedType.kind) {
-    case "Boolean":
-      return sharedType.value;
-    default:
-      reportDiagnostic(context.program, {
-        code: "shared-boolean",
-        target: sharedType,
-      });
-      return false;
-  }
-}
-
 /**
  * `@route` defines the relative route URI for the target operation
  *
@@ -588,9 +572,24 @@ function extractSharedValue(context: DecoratorContext, parameters?: Model): bool
 export function $route(context: DecoratorContext, entity: Type, path: string, parameters?: Model) {
   validateDecoratorUniqueOnNode(context, entity, $route);
 
+  // Handle the deprecated `shared` option
+  let shared = false;
+  const sharedValue = parameters?.properties.get("shared")?.type;
+  if (sharedValue !== undefined) {
+    reportDeprecated(context.program, "The `shared` option is deprecated, use the `@sharedRoute` decorator instead.", entity);
+    if (sharedValue.kind === "Boolean") {
+      shared = sharedValue.value;
+    } else {
+      reportDiagnostic(context.program, {
+        code: "shared-boolean",
+        target: sharedValue,
+      });
+    }
+  }
+
   setRoute(context, entity, {
     path,
-    shared: extractSharedValue(context, parameters),
+    shared,
   });
 }
 
diff --git a/packages/http/test/http-decorators.test.ts b/packages/http/test/http-decorators.test.ts
index c43eae583ef..6bf9ba8d142 100644
--- a/packages/http/test/http-decorators.test.ts
+++ b/packages/http/test/http-decorators.test.ts
@@ -245,10 +245,22 @@ describe("http: decorators", () => {
       ]);
     });
 
-    it("emit diagnostics when not all duplicated routes are declared shared", async () => {
+    it("emits diagnostic when deprecated `shared` option is used", async () => {
       const diagnostics = await runner.diagnose(`
         @route("/test", { shared: true }) op test(): string;
-        @route("/test", { shared: true }) op test2(): string;
+      `);
+      expectDiagnostics(diagnostics, [
+        {
+          code: "deprecated",
+          message: "Deprecated: The `shared` option is deprecated, use the `@sharedRoute` decorator instead."
+        },
+      ]);
+    });
+
+    it("emit diagnostics when not all duplicated routes are declared shared", async () => {
+      const diagnostics = await runner.diagnose(`
+        @route("/test") @sharedRoute op test(): string;
+        @route("/test") @sharedRoute op test2(): string;
         @route("/test") op test3(): string;
       `);
       expectDiagnostics(diagnostics, [
@@ -261,8 +273,8 @@ describe("http: decorators", () => {
 
     it("do not emit diagnostics when duplicated shared routes are applied", async () => {
       const diagnostics = await runner.diagnose(`
-        @route("/test", {shared: true}) op test(): string;
-        @route("/test", {shared: true}) op test2(): string;
+        @route("/test") @sharedRoute op test(): string;
+        @route("/test") @sharedRoute op test2(): string;
       `);
 
       expectDiagnosticEmpty(diagnostics);
@@ -273,6 +285,10 @@ describe("http: decorators", () => {
         @route("/test", {shared: "yes"}) op test(): string;
       `);
       expectDiagnostics(diagnostics, [
+        {
+          code: "deprecated",
+          message: "Deprecated: The `shared` option is deprecated, use the `@sharedRoute` decorator instead."
+        },
         {
           code: "@typespec/http/shared-boolean",
           message: `shared parameter must be a boolean.`,
diff --git a/packages/http/test/routes.test.ts b/packages/http/test/routes.test.ts
index 3f4e04d230d..5cec90b38f6 100644
--- a/packages/http/test/routes.test.ts
+++ b/packages/http/test/routes.test.ts
@@ -581,6 +581,7 @@ describe("http: routes", () => {
       const { get1, get2 } = (await runner.compile(`
         @route("/test")
         namespace Foo {
+          #suppress "deprecated"
           @test
           @route("/get1", { shared: true })
           op get1(): string;
@@ -588,6 +589,7 @@ describe("http: routes", () => {
 
         @route("/test")
         namespace Foo {
+          #suppress "deprecated"
           @test
           @route("/get2", { shared: false })
           op get2(): string;
diff --git a/packages/rest/test/routes.test.ts b/packages/rest/test/routes.test.ts
index 303f5cd7b75..b75c0b34982 100644
--- a/packages/rest/test/routes.test.ts
+++ b/packages/rest/test/routes.test.ts
@@ -454,11 +454,11 @@ describe("rest: routes", () => {
       @test
       @autoRoute
       @sharedRoute
-      op get1(@path name: string): string;
+      op get1(@path foo: string): string;
 
       @test
       @autoRoute
-      op get2(@path name: string): string;
+      op get2(@path bar: string): string;
     `)) as { get1: Operation; get2: Operation };
 
     strictEqual(isSharedRoute(runner.program, get1), true);

From 8cf9bd26a66f6e7bdf33b040a481a01404b5885b Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Tue, 18 Apr 2023 09:55:51 +0300
Subject: [PATCH 06/13] Format source

---
 packages/http/src/decorators.ts            | 18 +++++++++++-------
 packages/http/test/http-decorators.test.ts |  6 ++++--
 packages/http/test/routes.test.ts          |  2 +-
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/packages/http/src/decorators.ts b/packages/http/src/decorators.ts
index b6754ee0184..d079972a6a8 100644
--- a/packages/http/src/decorators.ts
+++ b/packages/http/src/decorators.ts
@@ -1,21 +1,21 @@
 import {
-  createDiagnosticCollector,
   DecoratorContext,
   Diagnostic,
   DiagnosticTarget,
-  reportDeprecated,
-  getDoc,
-  isArrayModelType,
   Model,
   ModelProperty,
   Namespace,
   Operation,
   Program,
-  setTypeSpecNamespace,
   Tuple,
   Type,
-  typespecTypeToJson,
   Union,
+  createDiagnosticCollector,
+  getDoc,
+  isArrayModelType,
+  reportDeprecated,
+  setTypeSpecNamespace,
+  typespecTypeToJson,
   validateDecoratorTarget,
   validateDecoratorUniqueOnNode,
 } from "@typespec/compiler";
@@ -576,7 +576,11 @@ export function $route(context: DecoratorContext, entity: Type, path: string, pa
   let shared = false;
   const sharedValue = parameters?.properties.get("shared")?.type;
   if (sharedValue !== undefined) {
-    reportDeprecated(context.program, "The `shared` option is deprecated, use the `@sharedRoute` decorator instead.", entity);
+    reportDeprecated(
+      context.program,
+      "The `shared` option is deprecated, use the `@sharedRoute` decorator instead.",
+      entity
+    );
     if (sharedValue.kind === "Boolean") {
       shared = sharedValue.value;
     } else {
diff --git a/packages/http/test/http-decorators.test.ts b/packages/http/test/http-decorators.test.ts
index 6bf9ba8d142..d2230dfd83e 100644
--- a/packages/http/test/http-decorators.test.ts
+++ b/packages/http/test/http-decorators.test.ts
@@ -252,7 +252,8 @@ describe("http: decorators", () => {
       expectDiagnostics(diagnostics, [
         {
           code: "deprecated",
-          message: "Deprecated: The `shared` option is deprecated, use the `@sharedRoute` decorator instead."
+          message:
+            "Deprecated: The `shared` option is deprecated, use the `@sharedRoute` decorator instead.",
         },
       ]);
     });
@@ -287,7 +288,8 @@ describe("http: decorators", () => {
       expectDiagnostics(diagnostics, [
         {
           code: "deprecated",
-          message: "Deprecated: The `shared` option is deprecated, use the `@sharedRoute` decorator instead."
+          message:
+            "Deprecated: The `shared` option is deprecated, use the `@sharedRoute` decorator instead.",
         },
         {
           code: "@typespec/http/shared-boolean",
diff --git a/packages/http/test/routes.test.ts b/packages/http/test/routes.test.ts
index 5cec90b38f6..5f12ade3370 100644
--- a/packages/http/test/routes.test.ts
+++ b/packages/http/test/routes.test.ts
@@ -1,7 +1,7 @@
 import { Operation } from "@typespec/compiler";
 import { expectDiagnosticEmpty, expectDiagnostics } from "@typespec/compiler/testing";
 import { deepStrictEqual, strictEqual } from "assert";
-import { getRoutePath, HttpOperation } from "../src/index.js";
+import { HttpOperation, getRoutePath } from "../src/index.js";
 import {
   compileOperations,
   createHttpTestRunner,

From edcc87dd4b1dc02b15bb3853e8d987b947b5e5ce Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Tue, 18 Apr 2023 10:05:47 +0300
Subject: [PATCH 07/13] Add `options` signature for `route` decorator

---
 packages/http/lib/http-decorators.tsp      | 8 +++++++-
 packages/http/src/decorators.ts            | 7 ++-----
 packages/http/src/lib.ts                   | 6 ------
 packages/http/test/http-decorators.test.ts | 9 ++-------
 4 files changed, 11 insertions(+), 19 deletions(-)

diff --git a/packages/http/lib/http-decorators.tsp b/packages/http/lib/http-decorators.tsp
index f1f67b183cf..61da390f27f 100644
--- a/packages/http/lib/http-decorators.tsp
+++ b/packages/http/lib/http-decorators.tsp
@@ -224,7 +224,13 @@ extern dec includeInapplicableMetadataInPayload(target: unknown, value: boolean)
  * op getWidget(@path id: string): Widget;
  * ```
  */
-extern dec route(target: Namespace | Interface | Operation, path: string, options?: object);
+extern dec route(
+  target: Namespace | Interface | Operation,
+  path: string,
+  options?: {
+    shared?: boolean,
+  }
+);
 
 /**
  * `@sharedRoute` marks the operation as sharing a route path with other operations.
diff --git a/packages/http/src/decorators.ts b/packages/http/src/decorators.ts
index d079972a6a8..1fb5942f544 100644
--- a/packages/http/src/decorators.ts
+++ b/packages/http/src/decorators.ts
@@ -581,13 +581,10 @@ export function $route(context: DecoratorContext, entity: Type, path: string, pa
       "The `shared` option is deprecated, use the `@sharedRoute` decorator instead.",
       entity
     );
+
+    // The type checker should have raised a diagnostic if the value isn't boolean
     if (sharedValue.kind === "Boolean") {
       shared = sharedValue.value;
-    } else {
-      reportDiagnostic(context.program, {
-        code: "shared-boolean",
-        target: sharedValue,
-      });
     }
   }
 
diff --git a/packages/http/src/lib.ts b/packages/http/src/lib.ts
index e0542bf3b14..931d53a3634 100644
--- a/packages/http/src/lib.ts
+++ b/packages/http/src/lib.ts
@@ -100,12 +100,6 @@ const libDefinition = {
         default: paramMessage`@useAuth ${"kind"} only accept Auth model, Tuple of auth model or union of auth model.`,
       },
     },
-    "shared-boolean": {
-      severity: "error",
-      messages: {
-        default: "shared parameter must be a boolean.",
-      },
-    },
     "shared-inconsistency": {
       severity: "error",
       messages: {
diff --git a/packages/http/test/http-decorators.test.ts b/packages/http/test/http-decorators.test.ts
index d2230dfd83e..7991aa559be 100644
--- a/packages/http/test/http-decorators.test.ts
+++ b/packages/http/test/http-decorators.test.ts
@@ -287,13 +287,8 @@ describe("http: decorators", () => {
       `);
       expectDiagnostics(diagnostics, [
         {
-          code: "deprecated",
-          message:
-            "Deprecated: The `shared` option is deprecated, use the `@sharedRoute` decorator instead.",
-        },
-        {
-          code: "@typespec/http/shared-boolean",
-          message: `shared parameter must be a boolean.`,
+          code: "invalid-argument",
+          message: `Argument '(anonymous model)' is not assignable to parameter of type '(anonymous model)'`,
         },
       ]);
     });

From 665dcf9ba498e412cdec5642a14ee918ccde4b77 Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Tue, 18 Apr 2023 17:04:59 +0300
Subject: [PATCH 08/13] Ensure @action operations have explicit name when using
 @sharedRoute

---
 packages/rest/src/lib.ts          |  6 ++++
 packages/rest/src/rest.ts         | 56 +++++++++++++++++++++++++++----
 packages/rest/src/validate.ts     | 32 ++++++++++++++++++
 packages/rest/test/routes.test.ts | 45 +++++++++++++++++++++++++
 4 files changed, 132 insertions(+), 7 deletions(-)

diff --git a/packages/rest/src/lib.ts b/packages/rest/src/lib.ts
index f46d2003e86..0f5882c5993 100644
--- a/packages/rest/src/lib.ts
+++ b/packages/rest/src/lib.ts
@@ -39,6 +39,12 @@ const libDefinition = {
         default: "Action name cannot be empty string.",
       },
     },
+    "shared-route-unspecified-action-name": {
+      severity: "error",
+      messages: {
+        default: paramMessage`An operation marked as '@sharedRoute' must have an explicit collection action name passed to '${"decoratorName"}'.`,
+      },
+    },
   },
 } as const;
 
diff --git a/packages/rest/src/rest.ts b/packages/rest/src/rest.ts
index 6ad7837fd4f..3bf8dffdccd 100644
--- a/packages/rest/src/rest.ts
+++ b/packages/rest/src/rest.ts
@@ -421,8 +421,11 @@ function lowerCaseFirstChar(str: string): string {
   return str[0].toLocaleLowerCase() + str.substring(1);
 }
 
-function makeActionName(op: Operation, name: string | undefined): string {
-  return lowerCaseFirstChar(name || op.name);
+function makeActionName(op: Operation, name: string | undefined): ActionDetails {
+  return {
+    name: lowerCaseFirstChar(name || op.name),
+    kind: name ? "specified" : "automatic",
+  };
 }
 
 const actionsSegmentKey = createStateSymbol("actionSegment");
@@ -435,6 +438,22 @@ export function getActionSegment(program: Program, entity: Type): string | undef
   return program.stateMap(actionsSegmentKey).get(entity);
 }
 
+/**
+ * Provides details about an action or collection action.
+ */
+export interface ActionDetails {
+  /**
+   * The name of the action
+   */
+  name: string;
+
+  /**
+   * Identifies whether the action's name was generated from the original
+   * operation name or if it was explicitly specified.
+   */
+  kind: "automatic" | "specified";
+}
+
 const actionsKey = createStateSymbol("actions");
 export function $action(context: DecoratorContext, entity: Operation, name?: string) {
   if (name === "") {
@@ -444,15 +463,26 @@ export function $action(context: DecoratorContext, entity: Operation, name?: str
     });
     return;
   }
+
   const action = makeActionName(entity, name);
-  context.call($actionSegment, entity, action);
+  context.call($actionSegment, entity, action.name);
   context.program.stateMap(actionsKey).set(entity, action);
 }
 
-export function getAction(program: Program, operation: Operation): string | null | undefined {
+/**
+ * Gets the ActionDetails for the specified operation if it has previously been marked with @action.
+ */
+export function getActionDetails(
+  program: Program,
+  operation: Operation
+): ActionDetails | undefined {
   return program.stateMap(actionsKey).get(operation);
 }
 
+export function getAction(program: Program, operation: Operation): string | null | undefined {
+  return getActionDetails(program, operation)?.name;
+}
+
 const collectionActionsKey = createStateSymbol("collectionActions");
 
 export function $collectionAction(
@@ -473,16 +503,28 @@ export function $collectionAction(
   }
 
   const action = makeActionName(entity, name);
-  context.call($actionSegment, entity, action);
+  context.call($actionSegment, entity, action.name);
 
-  context.program.stateMap(collectionActionsKey).set(entity, `${segment}/${action}`);
+  // Update the final name and store it
+  action.name = `${segment}/${action.name}`;
+  context.program.stateMap(collectionActionsKey).set(entity, action);
+}
+
+/**
+ * Gets the ActionDetails for the specified operation if it has previously been marked with @collectionAction.
+ */
+export function getCollectionActionDetails(
+  program: Program,
+  operation: Operation
+): ActionDetails | undefined {
+  return program.stateMap(collectionActionsKey).get(operation);
 }
 
 export function getCollectionAction(
   program: Program,
   operation: Operation
 ): string | null | undefined {
-  return program.stateMap(collectionActionsKey).get(operation);
+  return getCollectionActionDetails(program, operation)?.name;
 }
 
 const resourceLocationsKey = createStateSymbol("resourceLocations");
diff --git a/packages/rest/src/validate.ts b/packages/rest/src/validate.ts
index 48f6e09c3e1..3da0f5af67d 100644
--- a/packages/rest/src/validate.ts
+++ b/packages/rest/src/validate.ts
@@ -7,8 +7,10 @@ import {
   navigateTypesInNamespace,
   Program,
 } from "@typespec/compiler";
+import { isSharedRoute } from "@typespec/http";
 import { reportDiagnostic } from "./lib.js";
 import { getParentResource, getResourceTypeKey, ResourceKey } from "./resource.js";
+import { getActionDetails, getCollectionActionDetails } from "./rest.js";
 
 function checkForDuplicateResourceKeyNames(program: Program) {
   const seenTypes = new Set<string>();
@@ -60,8 +62,38 @@ function checkForDuplicateResourceKeyNames(program: Program) {
   }
 }
 
+function checkForSharedRouteUnnamedActions(program: Program) {
+  for (const service of listServices(program)) {
+    // If the model type is defined under the service namespace, check that the
+    // parent resource type(s) don't have the same key name as the
+    // current resource type.
+    navigateTypesInNamespace(service.type, {
+      operation: (op) => {
+        const actionDetails = getActionDetails(program, op);
+        if (
+          isSharedRoute(program, op) &&
+          (actionDetails?.kind === "automatic" ||
+            getCollectionActionDetails(program, op)?.kind === "automatic")
+        ) {
+          reportDiagnostic(program, {
+            code: "shared-route-unspecified-action-name",
+            target: op,
+            format: {
+              decoratorName: actionDetails ? "@action" : "@collectionAction",
+            },
+          });
+        }
+      },
+    });
+  }
+}
+
 export function $onValidate(program: Program) {
   // Make sure any defined resource types don't have any conflicts with parent
   // resource type key names
   checkForDuplicateResourceKeyNames(program);
+
+  // Ensure that all shared routes with an `@action` decorator have an
+  // explicitly named action
+  checkForSharedRouteUnnamedActions(program);
 }
diff --git a/packages/rest/test/routes.test.ts b/packages/rest/test/routes.test.ts
index b75c0b34982..6f9aac1cd2d 100644
--- a/packages/rest/test/routes.test.ts
+++ b/packages/rest/test/routes.test.ts
@@ -464,4 +464,49 @@ describe("rest: routes", () => {
     strictEqual(isSharedRoute(runner.program, get1), true);
     strictEqual(isSharedRoute(runner.program, get2), false);
   });
+
+  it("emits a diagnostic when @sharedRoute is used on action without explicit name", async () => {
+    const [_, diagnostics] = await compileOperations(
+      `
+      model Thing {
+        @key
+        @segment("things")
+        thingId: string;
+      }
+
+      @action
+      @autoRoute
+      @sharedRoute
+      op badAction(): {};
+
+      @action("good")
+      @autoRoute
+      @sharedRoute
+      op goodAction(): {};
+
+      @autoRoute
+      @sharedRoute
+      @collectionAction(Thing)
+      op badCollectionAction(): {};
+
+      @autoRoute
+      @sharedRoute
+      @collectionAction(Thing, "goodCollection")
+      op goodCollectionAction(): {};
+      `
+    );
+
+    expectDiagnostics(diagnostics, [
+      {
+        code: "@typespec/rest/shared-route-unspecified-action-name",
+        message:
+          "An operation marked as '@sharedRoute' must have an explicit collection action name passed to '@action'.",
+      },
+      {
+        code: "@typespec/rest/shared-route-unspecified-action-name",
+        message:
+          "An operation marked as '@sharedRoute' must have an explicit collection action name passed to '@collectionAction'.",
+      },
+    ]);
+  });
 });

From d2e7e258fdbfe40bcceeb4258020b8250c20aa06 Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Tue, 18 Apr 2023 17:07:05 +0300
Subject: [PATCH 09/13] Update Rush change files

---
 .../http/split-shared-route_2023-04-18-14-06.json      | 10 ++++++++++
 .../rest/split-shared-route_2023-04-18-14-06.json      | 10 ++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 common/changes/@typespec/http/split-shared-route_2023-04-18-14-06.json
 create mode 100644 common/changes/@typespec/rest/split-shared-route_2023-04-18-14-06.json

diff --git a/common/changes/@typespec/http/split-shared-route_2023-04-18-14-06.json b/common/changes/@typespec/http/split-shared-route_2023-04-18-14-06.json
new file mode 100644
index 00000000000..c7b42480d16
--- /dev/null
+++ b/common/changes/@typespec/http/split-shared-route_2023-04-18-14-06.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@typespec/http",
+      "comment": "Deprecate the `shared` option in the `@route` decorator.  `@sharedRoute` is the new way to accomplish the same behavior.",
+      "type": "none"
+    }
+  ],
+  "packageName": "@typespec/http"
+}
\ No newline at end of file
diff --git a/common/changes/@typespec/rest/split-shared-route_2023-04-18-14-06.json b/common/changes/@typespec/rest/split-shared-route_2023-04-18-14-06.json
new file mode 100644
index 00000000000..3dbd1229d14
--- /dev/null
+++ b/common/changes/@typespec/rest/split-shared-route_2023-04-18-14-06.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@typespec/rest",
+      "comment": "Add validation to ensure that @action or @collectionAction operations have a specified name when used with @sharedRoute",
+      "type": "none"
+    }
+  ],
+  "packageName": "@typespec/rest"
+}
\ No newline at end of file

From 279feea79d1e7ff18d126b744c2cc3fa064fd07c Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Tue, 18 Apr 2023 17:07:55 +0300
Subject: [PATCH 10/13] Update documentation

---
 docs/standard-library/http/reference/decorators.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/docs/standard-library/http/reference/decorators.md b/docs/standard-library/http/reference/decorators.md
index f2cdc4d8196..5076c235dcb 100644
--- a/docs/standard-library/http/reference/decorators.md
+++ b/docs/standard-library/http/reference/decorators.md
@@ -246,7 +246,7 @@ it will be used as a prefix to the route URI of the operation.
 `@route` can only be applied to operations, namespaces, and interfaces.
 
 ```typespec
-dec TypeSpec.Http.route(target: Namespace | Interface | Operation, path: string, options?: object)
+dec TypeSpec.Http.route(target: Namespace | Interface | Operation, path: string, options?: (anonymous model))
 ```
 
 #### Target
@@ -255,10 +255,10 @@ dec TypeSpec.Http.route(target: Namespace | Interface | Operation, path: string,
 
 #### Parameters
 
-| Name    | Type            | Description                                           |
-| ------- | --------------- | ----------------------------------------------------- |
-| path    | `scalar string` | Relative route path. Cannot include query parameters. |
-| options | `model object`  |                                                       |
+| Name    | Type                      | Description                                           |
+| ------- | ------------------------- | ----------------------------------------------------- |
+| path    | `scalar string`           | Relative route path. Cannot include query parameters. |
+| options | `model (anonymous model)` |                                                       |
 
 ### `@server` {#@TypeSpec.Http.server}
 

From 60d7fbb135383c58351c09bed645803fc6f77924 Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Tue, 18 Apr 2023 17:27:05 +0300
Subject: [PATCH 11/13] Update openapi3 shared route tests to use @sharedRoute

---
 .../split-shared-route_2023-04-18-14-27.json  | 10 ++++++
 packages/openapi3/test/shared-routes.test.ts  | 36 ++++++++++++-------
 2 files changed, 34 insertions(+), 12 deletions(-)
 create mode 100644 common/changes/@typespec/openapi3/split-shared-route_2023-04-18-14-27.json

diff --git a/common/changes/@typespec/openapi3/split-shared-route_2023-04-18-14-27.json b/common/changes/@typespec/openapi3/split-shared-route_2023-04-18-14-27.json
new file mode 100644
index 00000000000..d9a70151de5
--- /dev/null
+++ b/common/changes/@typespec/openapi3/split-shared-route_2023-04-18-14-27.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@typespec/openapi3",
+      "comment": "",
+      "type": "none"
+    }
+  ],
+  "packageName": "@typespec/openapi3"
+}
\ No newline at end of file
diff --git a/packages/openapi3/test/shared-routes.test.ts b/packages/openapi3/test/shared-routes.test.ts
index 81523e44b16..49893304096 100644
--- a/packages/openapi3/test/shared-routes.test.ts
+++ b/packages/openapi3/test/shared-routes.test.ts
@@ -41,12 +41,14 @@ describe("openapi3: shared routes", () => {
           id: string;
         }
 
+        @sharedRoute
         @operationId("List_ResourceGroup")
-        @route("/sharedroutes/resources", { shared: true })
+        @route("/sharedroutes/resources")
         op listByResourceGroup(...Resource, @query resourceGroup: string, @query foo: string): Resource[];
 
+        @sharedRoute
         @operationId("List_Subscription")
-        @route("/sharedroutes/resources", { shared: true })
+        @route("/sharedroutes/resources")
         op listBySubscription(...Resource, @query subscription: string, @query foo: string): Resource[];
       }
       `
@@ -96,10 +98,12 @@ describe("openapi3: shared routes", () => {
           id: string;
         }
 
-        @route("/sharedroutes/resources", { shared: true })
+        @sharedRoute
+        @route("/sharedroutes/resources")
         op listByResourceGroup(...Resource, @query filter: "resourceGroup"): Resource[];
 
-        @route("/sharedroutes/resources", { shared: true })
+        @sharedRoute
+        @route("/sharedroutes/resources")
         op listBySubscription(...Resource, @query filter: "subscription"): Resource[];
       }
       `
@@ -135,10 +139,12 @@ describe("openapi3: shared routes", () => {
           id: string;
         }
 
-        @route("/sharedroutes/resources", { shared: true })
+        @sharedRoute
+        @route("/sharedroutes/resources")
         op listByResourceGroup(...Resource, @query filter: "resourceGroup"): Resource[];
 
-        @route("/sharedroutes/resources", { shared: true })
+        @sharedRoute
+        @route("/sharedroutes/resources")
         op listBySubscription(...Resource, @header filter: "subscription"): Resource[];
       }
       `
@@ -183,10 +189,12 @@ describe("openapi3: shared routes", () => {
           id: string;
         }
 
-        @route("/sharedroutes/resources", { shared: true })
+        @sharedRoute
+        @route("/sharedroutes/resources")
         op returnsInt(...Resource, @query options: string): int32;
 
-        @route("/sharedroutes/resources", { shared: true })
+        @sharedRoute
+        @route("/sharedroutes/resources")
         op returnsString(...Resource, @query options: string): string;
       }
       `
@@ -224,10 +232,12 @@ describe("openapi3: shared routes", () => {
       `
       @service({title: "My Service"})
       namespace Foo {
-        @route("/sharedroutes/resources", { shared: true })
+        @sharedRoute
+        @route("/sharedroutes/resources")
         op processInt(@body body: int32, @query options: string): void;
 
-        @route("/sharedroutes/resources", { shared: true })
+        @sharedRoute
+        @route("/sharedroutes/resources")
         op processString(@body body: string, @query options: string): void;
       }
       `
@@ -261,10 +271,12 @@ describe("openapi3: shared routes", () => {
       `
       @service({title: "My Service"})
       namespace Foo {
-        @route("/process", { shared: true })
+        @sharedRoute
+        @route("/process")
         op processInt(@body body: int32, @query options: string): int32;
 
-        @route("/process", { shared: true })
+        @sharedRoute
+        @route("/process")
         op processString(@body body: string, @query options: string): string;
       }
       `

From 1c3507189795b97a26fda589530188dae1fd7faf Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Wed, 19 Apr 2023 14:15:16 +0300
Subject: [PATCH 12/13] PR feedback

---
 packages/rest/src/rest.ts         | 8 +++++++-
 packages/rest/test/routes.test.ts | 4 ++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/packages/rest/src/rest.ts b/packages/rest/src/rest.ts
index 3bf8dffdccd..7ce7f9fad23 100644
--- a/packages/rest/src/rest.ts
+++ b/packages/rest/src/rest.ts
@@ -79,7 +79,7 @@ function getResourceOperationHttpVerb(
   return (
     getOperationVerb(program, operation) ??
     (resourceOperation && resourceOperationToVerb[resourceOperation.operation]) ??
-    (getAction(program, operation) || getCollectionAction(program, operation) ? "post" : undefined)
+    (getActionDetails(program, operation) || getCollectionActionDetails(program, operation) ? "post" : undefined)
   );
 }
 
@@ -479,6 +479,9 @@ export function getActionDetails(
   return program.stateMap(actionsKey).get(operation);
 }
 
+/**
+ * @deprecated Use getActionDetails instead.
+ */
 export function getAction(program: Program, operation: Operation): string | null | undefined {
   return getActionDetails(program, operation)?.name;
 }
@@ -520,6 +523,9 @@ export function getCollectionActionDetails(
   return program.stateMap(collectionActionsKey).get(operation);
 }
 
+/**
+ * @deprecated Use getCollectionActionDetails instead.
+ */
 export function getCollectionAction(
   program: Program,
   operation: Operation
diff --git a/packages/rest/test/routes.test.ts b/packages/rest/test/routes.test.ts
index 6f9aac1cd2d..7c49f11f1e0 100644
--- a/packages/rest/test/routes.test.ts
+++ b/packages/rest/test/routes.test.ts
@@ -454,11 +454,11 @@ describe("rest: routes", () => {
       @test
       @autoRoute
       @sharedRoute
-      op get1(@path foo: string): string;
+      op get1(@segment("get1") @path name: string): string;
 
       @test
       @autoRoute
-      op get2(@path bar: string): string;
+      op get2(@segment("get2") @path name: string): string;
     `)) as { get1: Operation; get2: Operation };
 
     strictEqual(isSharedRoute(runner.program, get1), true);

From 54a0d0464c934d19cbf826a564fbc89b8d800575 Mon Sep 17 00:00:00 2001
From: David Wilson <david@daviwil.com>
Date: Wed, 19 Apr 2023 14:33:45 +0300
Subject: [PATCH 13/13] Format

---
 packages/rest/src/rest.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/rest/src/rest.ts b/packages/rest/src/rest.ts
index 7ce7f9fad23..73ab672b8c3 100644
--- a/packages/rest/src/rest.ts
+++ b/packages/rest/src/rest.ts
@@ -79,7 +79,9 @@ function getResourceOperationHttpVerb(
   return (
     getOperationVerb(program, operation) ??
     (resourceOperation && resourceOperationToVerb[resourceOperation.operation]) ??
-    (getActionDetails(program, operation) || getCollectionActionDetails(program, operation) ? "post" : undefined)
+    (getActionDetails(program, operation) || getCollectionActionDetails(program, operation)
+      ? "post"
+      : undefined)
   );
 }