Fix response examples with union not showing up correctly (#4046)

fix #4033

A few issues:
- Example being empty 
- Example duplicating for all responses instead of mapping to the right
one

---------

Co-authored-by: Christopher Radek <14189820+chrisradek@users.noreply.github.com>

.chronus/changes/fix-response-examples-2024-6-29-22-38-45.md

@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/compiler"
+---
+
+Fix type comparison of literal and scalar when in projection context

.chronus/changes/fix-response-examples-2024-6-30-15-26-28.md

@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/openapi3"
+---
+
+Fix issue where operation example would produce an empty object when `@body`/`@bodyRoot` was used 

.chronus/changes/fix-response-examples-2024-6-30-15-59-29.md

@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/openapi3"
+---
+
+Fix operation response body examples showing up for each response.

.chronus/changes/fix-response-examples-2024-6-30-22-22-9.md

@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: feature
+packages:
+  - "@typespec/http"
+---
+
+API: Expose `properties: HttpProperty[]` on operation parameter and response which reference all the properties of interest(Body, statusCode, contentType, implicitBodyProperty, etc.)

packages/compiler/src/core/checker.ts

@@ -7874,7 +7874,7 @@ export function createChecker(program: Program): Checker {
 
   function isNumericAssignableToNumericScalar(source: Numeric, target: Scalar) {
     // if the target does not derive from numeric, then it can't be assigned a numeric literal
-    if (!areScalarsRelated(target, getStdType("numeric"))) {
+    if (!areScalarsRelated((target.projectionBase as any) ?? target, getStdType("numeric"))) {
       return false;
     }
 
@@ -7902,7 +7902,7 @@ export function createChecker(program: Program): Checker {
   }
 
   function isStringLiteralRelatedTo(source: StringLiteral | StringTemplate, target: Scalar) {
-    if (!areScalarsRelated(target, getStdType("string"))) {
+    if (!areScalarsRelated((target.projectionBase as any) ?? target, getStdType("string"))) {
       return false;
     }
     if (source.kind === "StringTemplate") {

packages/http/src/http-property.ts

@@ -9,7 +9,6 @@ import {
   type ModelProperty,
   type Program,
 } from "@typespec/compiler";
-import { Queue } from "@typespec/compiler/utils";
 import {
   getHeaderFieldOptions,
   getPathParamOptions,
@@ -36,6 +35,8 @@ export type HttpProperty =
 
 export interface HttpPropertyBase {
   readonly property: ModelProperty;
+  /** Path from the root of the operation parameters/returnType to the property. */
+  readonly path: (string | number)[];
 }
 
 export interface HeaderProperty extends HttpPropertyBase {
@@ -78,14 +79,17 @@ export interface GetHttpPropertyOptions {
 /**
  * Find the type of a property in a model
  */
-export function getHttpProperty(
+function getHttpProperty(
   program: Program,
   property: ModelProperty,
+  path: (string | number)[],
   options: GetHttpPropertyOptions = {}
 ): [HttpProperty, readonly Diagnostic[]] {
   const diagnostics: Diagnostic[] = [];
-  function createResult<T extends HttpProperty>(opts: T): [T, readonly Diagnostic[]] {
-    return [{ ...opts, property } as any, diagnostics];
+  function createResult<T extends Omit<HttpProperty, "path" | "property">>(
+    opts: T
+  ): [HttpProperty & T, readonly Diagnostic[]] {
+    return [{ ...opts, property, path } as any, diagnostics];
   }
 
   const annotations = {
@@ -106,10 +110,9 @@ export function getHttpProperty(
           name: property.name,
           type: "path",
         },
-        property,
       });
     }
-    return [{ kind: "bodyProperty", property }, []];
+    return createResult({ kind: "bodyProperty" });
   } else if (defined.length > 1) {
     diagnostics.push(
       createDiagnostic({
@@ -122,24 +125,24 @@ export function getHttpProperty(
 
   if (annotations.header) {
     if (annotations.header.name.toLowerCase() === "content-type") {
-      return createResult({ kind: "contentType", property });
+      return createResult({ kind: "contentType" });
     } else {
-      return createResult({ kind: "header", options: annotations.header, property });
+      return createResult({ kind: "header", options: annotations.header });
     }
   } else if (annotations.query) {
-    return createResult({ kind: "query", options: annotations.query, property });
+    return createResult({ kind: "query", options: annotations.query });
   } else if (annotations.path) {
-    return createResult({ kind: "path", options: annotations.path, property });
+    return createResult({ kind: "path", options: annotations.path });
   } else if (annotations.statusCode) {
-    return createResult({ kind: "statusCode", property });
+    return createResult({ kind: "statusCode" });
   } else if (annotations.body) {
-    return createResult({ kind: "body", property });
+    return createResult({ kind: "body" });
   } else if (annotations.bodyRoot) {
-    return createResult({ kind: "bodyRoot", property });
+    return createResult({ kind: "bodyRoot" });
   } else if (annotations.multipartBody) {
-    return createResult({ kind: "multipartBody", property });
+    return createResult({ kind: "multipartBody" });
   }
-  compilerAssert(false, `Unexpected http property type`, property);
+  compilerAssert(false, `Unexpected http property type`);
 }
 
 /**
@@ -161,53 +164,57 @@ export function resolvePayloadProperties(
   }
 
   const visited = new Set();
-  const queue = new Queue<[Model, ModelProperty | undefined]>([[type, undefined]]);
-
-  while (!queue.isEmpty()) {
-    const [model, rootOpt] = queue.dequeue();
+  function checkModel(model: Model, path: string[]) {
     visited.add(model);
-
+    let foundBody = false;
+    let foundBodyProperty = false;
     for (const property of walkPropertiesInherited(model)) {
-      const root = rootOpt ?? property;
+      const propPath = [...path, property.name];
 
       if (!isVisible(program, property, visibility)) {
         continue;
       }
 
-      let httpProperty = diagnostics.pipe(getHttpProperty(program, property, options));
+      let httpProperty = diagnostics.pipe(getHttpProperty(program, property, propPath, options));
       if (shouldTreatAsBodyProperty(httpProperty, visibility)) {
-        httpProperty = { kind: "bodyProperty", property };
+        httpProperty = { kind: "bodyProperty", property, path: propPath };
       }
-      httpProperties.set(property, httpProperty);
+
       if (
-        property !== root &&
-        (httpProperty.kind === "body" ||
-          httpProperty.kind === "bodyRoot" ||
-          httpProperty.kind === "multipartBody")
+        httpProperty.kind === "body" ||
+        httpProperty.kind === "bodyRoot" ||
+        httpProperty.kind === "multipartBody"
       ) {
-        const parent = httpProperties.get(root);
-        if (parent?.kind === "bodyProperty") {
-          httpProperties.delete(root);
-        }
-      }
-      if (httpProperty.kind === "body" || httpProperty.kind === "multipartBody") {
-        continue; // We ignore any properties under `@body` or `@multipartBody`
+        foundBody = true;
       }
 
       if (
-        property.type.kind === "Model" &&
-        !type.indexer &&
-        type.properties.size > 0 &&
+        !(httpProperty.kind === "body" || httpProperty.kind === "multipartBody") &&
+        isModelWithProperties(property.type) &&
         !visited.has(property.type)
       ) {
-        queue.enqueue([property.type, root]);
+        if (checkModel(property.type, propPath)) {
+          foundBody = true;
+          continue;
+        }
+      }
+      if (httpProperty.kind === "bodyProperty") {
+        foundBodyProperty = true;
       }
+      httpProperties.set(property, httpProperty);
     }
+    return foundBody && !foundBodyProperty;
   }
 
+  checkModel(type, []);
+
   return diagnostics.wrap([...httpProperties.values()]);
 }
 
+function isModelWithProperties(type: Type): type is Model {
+  return type.kind === "Model" && !type.indexer && type.properties.size > 0;
+}
+
 function shouldTreatAsBodyProperty(property: HttpProperty, visibility: Visibility): boolean {
   if (visibility & Visibility.Read) {
     return property.kind === "query" || property.kind === "path";

packages/http/src/index.ts

@@ -5,6 +5,7 @@ export { HttpPartOptions } from "../generated-defs/TypeSpec.Http.Private.js";
 export * from "./auth.js";
 export * from "./content-types.js";
 export * from "./decorators.js";
+export type { HttpProperty } from "./http-property.js";
 export * from "./metadata.js";
 export * from "./operations.js";
 export * from "./parameters.js";

packages/http/src/parameters.ts

@@ -96,6 +96,7 @@ function getOperationParametersForVerb(
   const body = resolvedBody;
 
   return diagnostics.wrap({
+    properties: metadata,
     parameters,
     verb,
     body,

packages/http/src/responses.ts

@@ -135,9 +135,10 @@ function processResponseType(
       response.responses.push({
         body: resolvedBody,
         headers,
+        properties: metadata,
       });
     } else {
-      response.responses.push({ headers });
+      response.responses.push({ headers, properties: metadata });
     }
     responses.set(statusCode, response);
   }

packages/http/src/types.ts

@@ -10,7 +10,7 @@ import {
   Tuple,
   Type,
 } from "@typespec/compiler";
-import { HeaderProperty } from "./http-property.js";
+import { HeaderProperty, HttpProperty } from "./http-property.js";
 
 /**
  * @deprecated use `HttpOperation`. To remove in November 2022 release.
@@ -332,6 +332,9 @@ export type HttpOperationRequestBody = HttpOperationBody;
 export type HttpOperationResponseBody = HttpOperationBody;
 
 export interface HttpOperationParameters {
+  /** Http properties */
+  readonly properties: HttpProperty[];
+
   parameters: HttpOperationParameter[];
 
   body?: HttpOperationBody | HttpOperationMultipartBody;
@@ -441,6 +444,9 @@ export interface HttpOperationResponse {
 }
 
 export interface HttpOperationResponseContent {
+  /** Http properties for this response */
+  readonly properties: HttpProperty[];
+
   headers?: Record<string, ModelProperty>;
   body?: HttpOperationBody | HttpOperationMultipartBody;
 }

packages/http/test/parameters.test.ts

@@ -41,6 +41,30 @@ it("emit diagnostic when there is an unannotated parameter and a @body param", a
   });
 });
 
+it("emit diagnostic when there is an unannotated parameter and a nested @body param", async () => {
+  const [_, diagnostics] = await compileOperations(`
+      @get op get(param1: string, nested: {@body param2: string}): void;
+    `);
+
+  expectDiagnostics(diagnostics, {
+    code: "@typespec/http/duplicate-body",
+    message:
+      "Operation has a @body and an unannotated parameter. There can only be one representing the body",
+  });
+});
+
+it("emit diagnostic when there is annotated param and @body nested together", async () => {
+  const [_, diagnostics] = await compileOperations(`
+      @get op get(nested: {param1: string, @body param2: string}): void;
+    `);
+
+  expectDiagnostics(diagnostics, {
+    code: "@typespec/http/duplicate-body",
+    message:
+      "Operation has a @body and an unannotated parameter. There can only be one representing the body",
+  });
+});
+
 it("emit diagnostic when there are multiple @body param", async () => {
   const [_, diagnostics] = await compileOperations(`
       @get op get(@query select: string, @body param1: string, @body param2: string): string;