OpenAPI3: emit all properties for unreferenced schemas (#2620)

Fix #2571.

**BREAKING CHANGE**: Since the previous behavior was to emit
unreferenced schemas with Read visibility, this change can produce a
breaking change in Swagger if unreferenced schemas were previously
emitted that had write visibility properties stripped.

common/changes/@typespec/openapi3/unreferencedVisibilityFix_2023-11-01-16-22.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@typespec/openapi3",
+      "comment": "Emitter will now emit all properties on unreferenced schemas.",
+      "type": "none"
+    }
+  ],
+  "packageName": "@typespec/openapi3"
+}

packages/openapi3/src/openapi.ts

@@ -1295,7 +1295,7 @@ function createOAPIEmitter(
           !paramModels.has(type) &&
           !shouldInline(program, type)
         ) {
-          callSchemaEmitter(type, Visibility.Read);
+          callSchemaEmitter(type, Visibility.All);
         }
       };
       const skipSubNamespaces = isGlobalNamespace(program, serviceNamespace);

packages/openapi3/src/visibility-usage.ts

@@ -34,9 +34,10 @@ export function resolveVisibilityUsage(
   const reachableTypes = new Set<Type>(usages.keys());
 
   if (!omitUnreachableTypes) {
+    // Evaluate all unreferenced types and the types they reference with Visibility.All
     const trackType = (type: Type) => {
       if (!usages.has(type)) {
-        navigateReferencedTypes(type, Visibility.Read, (type, vis) =>
+        navigateReferencedTypes(type, Visibility.All, (type, vis) =>
           trackUsageExact(usages, type, vis)
         );
       }

packages/openapi3/test/metadata.test.ts

@@ -2,6 +2,94 @@ import { deepStrictEqual } from "assert";
 import { openApiFor } from "./test-host.js";
 
 describe("openapi3: metadata", () => {
+  it("will expose all properties on unreferenced models but filter properties on referenced models", async () => {
+    const res = await openApiFor(`
+      model M {
+        @visibility("read") r: string;
+        @visibility("create", "update") uc?: string;
+        @visibility("read", "create") rc?: string;
+        @visibility("read", "update", "create") ruc?: string;
+      }
+    `);
+
+    deepStrictEqual(res.components.schemas, {
+      M: {
+        type: "object",
+        properties: {
+          r: { type: "string", readOnly: true },
+          uc: { type: "string" },
+          rc: { type: "string" },
+          ruc: { type: "string" },
+        },
+        required: ["r"],
+      },
+    });
+  });
+
+  it("prioritizes read visibility when referenced and unreferenced models share schemas", async () => {
+    const res = await openApiFor(`
+      model Shared {
+        @visibility("create", "update") password: string;
+        prop: string;
+      }
+
+      model Unreferenced {
+        @visibility("read") r: string;
+        @visibility("create") c: string;
+        shared: Shared;
+      }
+
+      model Referenced {
+        @visibility("read") r: string;
+        @visibility("create") c: string;
+        shared: Shared;
+      }
+
+      @get op get(): Referenced;
+    `);
+
+    deepStrictEqual(res.components.schemas, {
+      Referenced: {
+        type: "object",
+        properties: {
+          r: { type: "string", readOnly: true },
+          shared: { $ref: "#/components/schemas/Shared" },
+        },
+        required: ["r", "shared"],
+      },
+      Shared: {
+        type: "object",
+        required: ["prop"],
+        properties: {
+          prop: {
+            type: "string",
+          },
+        },
+      },
+      SharedReadOrCreateOrUpdateOrDeleteOrQuery: {
+        type: "object",
+        required: ["password", "prop"],
+        properties: {
+          password: {
+            type: "string",
+          },
+          prop: {
+            type: "string",
+          },
+        },
+      },
+      Unreferenced: {
+        type: "object",
+        properties: {
+          c: { type: "string" },
+          r: { type: "string", readOnly: true },
+          shared: { $ref: "#/components/schemas/SharedReadOrCreateOrUpdateOrDeleteOrQuery" },
+        },
+        required: ["r", "c", "shared"],
+      },
+    });
+  });
+
   it("will expose create visibility properties on PATCH model using @requestVisibility", async () => {
     const res = await openApiFor(`
       model M {

packages/samples/test/output/visibility/@typespec/openapi3/openapi.yaml

@@ -103,6 +103,8 @@ components:
         id:
           type: string
           readOnly: true
+        secret:
+          type: string
         name:
           type: string
         test:
@@ -112,7 +114,7 @@ components:
         relatives:
           type: array
           items:
-            $ref: '#/components/schemas/PersonRelative'
+            $ref: '#/components/schemas/PersonRelativeReadOrCreateOrUpdateOrDeleteOrQueryItem'
     Person:
       type: object
       required:
@@ -174,6 +176,31 @@ components:
           type: array
           items:
             $ref: '#/components/schemas/PersonRelativeCreateOrUpdateItem'
+    PersonReadOrCreateOrUpdateOrDeleteOrQueryItem:
+      type: object
+      required:
+        - id
+        - secret
+        - name
+        - test
+        - other
+        - relatives
+      properties:
+        id:
+          type: string
+          readOnly: true
+        secret:
+          type: string
+        name:
+          type: string
+        test:
+          type: string
+        other:
+          type: string
+        relatives:
+          type: array
+          items:
+            $ref: '#/components/schemas/PersonRelativeReadOrCreateOrUpdateOrDeleteOrQueryItem'
     PersonRelative:
       type: object
       required:
@@ -204,6 +231,16 @@ components:
           $ref: '#/components/schemas/PersonCreateOrUpdateItem'
         relationship:
           type: string
+    PersonRelativeReadOrCreateOrUpdateOrDeleteOrQueryItem:
+      type: object
+      required:
+        - person
+        - relationship
+      properties:
+        person:
+          $ref: '#/components/schemas/PersonReadOrCreateOrUpdateOrDeleteOrQueryItem'
+        relationship:
+          type: string
     PersonRelativeUpdateItem:
       type: object
       required: