Rremove use of deprecated getDiscriminatedUnion in JS emitter (microsoft#6306)

This change removed the use of the deprecated overload on the JS emitter
and adds support for models in the `$.type.getDiscriminator` typekit

---------

Co-authored-by: Timothee Guerin <tiguerin@microsoft.com>
Co-authored-by: Timothee Guerin <timothee.guerin@outlook.com>
# Conflicts:
#	pnpm-lock.yaml

Author: 2 people

.chronus/changes/feature-remove-use-of-deprecated-union-2025-2-6-19-54-30.md

@@ -0,0 +1,9 @@
+---
+changeKind: deprecation
+packages:
+  - "@typespec/compiler"
+  - "@typespec/http-client-js"
+  - "@typespec/http-client"
+---
+
+Remove the use of deprecated getDiscriminatedUnion

.chronus/changes/feature-remove-use-of-deprecated-union-2025-2-7-2-59-51.md

@@ -0,0 +1,7 @@
+---
+changeKind: internal
+packages:
+  - "@typespec/emitter-framework"
+---
+
+Remove use of deprecated getDiscriminatedUnion overload

packages/compiler/src/experimental/typekit/kits/model.ts

@@ -1,4 +1,10 @@
 import { getEffectiveModelType } from "../../../core/checker.js";
+import { ignoreDiagnostics } from "../../../core/diagnostics.js";
+import {
+  DiscriminatedUnionLegacy,
+  getDiscriminatedUnionFromInheritance,
+} from "../../../core/helpers/discriminator-utils.js";
+import { getDiscriminator } from "../../../core/intrinsic-type-state.js";
 import type {
   Model,
   ModelIndexer,
@@ -116,6 +122,11 @@ export interface ModelKit {
    * @returns The record representing additional properties, or undefined if there are none.
    */
   getAdditionalPropertiesRecord(model: Model): Model | undefined;
+  /**
+   * Resolves a discriminated union for the given model from inheritance.
+   * @param type Model to resolve the discriminated union for.
+   */
+  getDiscriminatedUnion(model: Model): DiscriminatedUnionLegacy | undefined;
 }
 
 interface TypekitExtension {
@@ -234,5 +245,13 @@ defineKit<TypekitExtension>({
 
       return undefined;
     },
+    getDiscriminatedUnion(model) {
+      const discriminator = getDiscriminator(this.program, model);
+      if (!discriminator) {
+        return undefined;
+      }
+
+      return ignoreDiagnostics(getDiscriminatedUnionFromInheritance(model, discriminator));
+    },
   },
 });

packages/compiler/src/experimental/typekit/kits/type.ts

@@ -1,7 +1,5 @@
-import {
-  DiscriminatedUnion,
-  getDiscriminatedUnion,
-} from "../../../core/helpers/discriminator-utils.js";
+import { ignoreDiagnostics } from "../../../core/diagnostics.js";
+import { getDiscriminatedUnion } from "../../../core/helpers/discriminator-utils.js";
 import { getLocationContext } from "../../../core/helpers/location-context.js";
 import {
   Discriminator,
@@ -20,6 +18,7 @@ import { Enum, Model, Scalar, Union, type Type } from "../../../core/types.js";
 import { getDoc, getSummary } from "../../../lib/decorators.js";
 import { resolveEncodedName } from "../../../lib/encoded-names.js";
 import { defineKit } from "../define-kit.js";
+import { $ } from "../index.js";
 import { copyMap } from "../utils.js";
 import { getPlausibleName } from "../utils/get-plausible-name.js";
 
@@ -65,11 +64,6 @@ export interface TypeTypekit {
    * @param type The scalar to get the name of.z
    */
   getPlausibleName(type: Model | Union | Enum | Scalar): string;
-  /**
-   * Resolves a discriminated union for the given model or union.
-   * @param type Model or Union to resolve the discriminated union for.
-   */
-  getDiscriminatedUnion(type: Union): DiscriminatedUnion | undefined;
   /**
    * Resolves the discriminator for a discriminated union. Returns undefined if the type is not a discriminated union.
    * @param type
@@ -236,11 +230,18 @@ defineKit<TypekitExtension>({
       return getPlausibleName(type);
     },
     getDiscriminator(type) {
-      return getDiscriminator(this.program, type);
-    },
-    getDiscriminatedUnion(type) {
-      const [union] = getDiscriminatedUnion(this.program, type);
-      return union;
+      let discriminator: Discriminator | undefined;
+      if ($.model.is(type)) {
+        discriminator = getDiscriminator(this.program, type);
+      } else {
+        const unionDiscriminator = ignoreDiagnostics(getDiscriminatedUnion(this.program, type));
+        const propertyName = unionDiscriminator?.options.discriminatorPropertyName;
+        if (propertyName) {
+          discriminator = { propertyName };
+        }
+      }
+
+      return discriminator;
     },
     maxValue(type) {
       return getMaxValue(this.program, type);

packages/compiler/src/experimental/typekit/kits/union.ts

@@ -1,4 +1,8 @@
 import { ignoreDiagnostics } from "../../../core/diagnostics.js";
+import {
+  DiscriminatedUnion,
+  getDiscriminatedUnion,
+} from "../../../core/helpers/discriminator-utils.js";
 import type { Type, Union, UnionVariant } from "../../../core/types.js";
 import { createRekeyableMap } from "../../../utils/misc.js";
 import { defineKit } from "../define-kit.js";
@@ -73,6 +77,11 @@ export interface UnionKit {
    * @param type Uniton to check if it is an expression
    */
   isExpression(type: Union): boolean;
+  /**
+   * Resolves a discriminated union for the given union.
+   * @param type Union to resolve the discriminated union for.
+   */
+  getDiscriminatedUnion(type: Union): DiscriminatedUnion | undefined;
 }
 
 interface TypekitExtension {
@@ -172,5 +181,8 @@ export const UnionKit = defineKit<TypekitExtension>({
     isExpression(type) {
       return type.name === undefined || type.name === "";
     },
+    getDiscriminatedUnion(type) {
+      return ignoreDiagnostics(getDiscriminatedUnion(this.program, type));
+    },
   },
 });

packages/emitter-framework/src/typescript/components/type-transform.tsx

@@ -2,7 +2,6 @@ import { Children, code, For, mapJoin, Refkey, refkey } from "@alloy-js/core";
 import * as ts from "@alloy-js/typescript";
 import {
   Discriminator,
-  getDiscriminatedUnion,
   Model,
   ModelProperty,
   RekeyableMap,
@@ -57,7 +56,13 @@ interface DiscriminateExpressionProps {
 }
 
 function DiscriminateExpression(props: DiscriminateExpressionProps) {
-  const [discriminatedUnion] = getDiscriminatedUnion(props.type, props.discriminator)!;
+  const discriminatedUnion = $.model.is(props.type)
+    ? $.model.getDiscriminatedUnion(props.type)
+    : $.union.getDiscriminatedUnion(props.type);
+
+  if (!discriminatedUnion) {
+    return code`return item as any`;
+  }
 
   const discriminatorRef = `item.${props.discriminator.propertyName}`;
 
@@ -66,8 +71,10 @@ function DiscriminateExpression(props: DiscriminateExpressionProps) {
   return item as any;
   `;
 
+  const variants: Map<string, Type> = discriminatedUnion.variants;
+
   return (
-    <For each={discriminatedUnion.variants} ender={unhandledVariant}>
+    <For each={variants} ender={unhandledVariant}>
       {(name, variant) => {
         return code`
       if( ${discriminatorRef} === ${JSON.stringify(name)}) {
@@ -331,7 +338,7 @@ function needsTransform(type: Type): boolean {
 /**
  * This component represents a function call to transform a type
  */
-export function TypeTransformCall(props: TypeTransformCallProps) {
+export function TypeTransformCall(props: TypeTransformCallProps): Children {
   const collapsedProperty = getCollapsedProperty(props.type, props.collapse ?? false);
   const itemPath = collapsedProperty
     ? [...(props.itemPath ?? []), collapsedProperty.name]

packages/http-client-js/package.json

@@ -67,7 +67,6 @@
     "@vitest/ui": "^3.0.7",
     "picocolors": "~1.1.1",
     "concurrently": "^9.1.2",
-    "dotenv": "^16.4.7",
     "execa": "^9.5.2",
     "fs-extra": "^11.2.0",
     "globby": "~14.1.0",

packages/http-client-js/src/components/testing/client-options.tsx

@@ -1,7 +1,4 @@
 import * as ay from "@alloy-js/core";
-import { config } from "dotenv";
-
-config();
 
 export interface ClientTestOptions {}
 

packages/http-client-js/src/components/transforms/json/json-transform-discriminator.tsx

@@ -1,14 +1,6 @@
 import * as ay from "@alloy-js/core";
 import * as ts from "@alloy-js/typescript";
-import {
-  DiscriminatedUnion,
-  DiscriminatedUnionLegacy,
-  Discriminator,
-  getDiscriminatedUnion,
-  ignoreDiagnostics,
-  Model,
-  Union,
-} from "@typespec/compiler";
+import { Discriminator, Model, Union } from "@typespec/compiler";
 import { $ } from "@typespec/compiler/experimental/typekit";
 import { JsonTransform } from "./json-transform.jsx";
 
@@ -20,17 +12,11 @@ export interface JsonTransformDiscriminatorProps {
 }
 
 export function JsonTransformDiscriminator(props: JsonTransformDiscriminatorProps) {
-  let discriminatedUnion: DiscriminatedUnion | DiscriminatedUnionLegacy | undefined = $.union.is(
-    props.type,
-  )
-    ? $.type.getDiscriminatedUnion(props.type)
-    : undefined;
+  const discriminatedUnion = $.model.is(props.type)
+    ? $.model.getDiscriminatedUnion(props.type)
+    : $.union.getDiscriminatedUnion(props.type);
 
-  let propertyName: string | undefined = discriminatedUnion?.options.discriminatorPropertyName;
-  if (!discriminatedUnion && props.discriminator) {
-    discriminatedUnion = ignoreDiagnostics(getDiscriminatedUnion(props.type, props.discriminator));
-    propertyName = props.discriminator.propertyName;
-  }
+  const propertyName = props.discriminator.propertyName;
 
   if (!discriminatedUnion || !propertyName) {
     return ay.code`${props.itemRef}`;

packages/http-client-js/test/e2e/http/type/property/additional-properties/spreads.test.ts

@@ -377,7 +377,10 @@ describe("Missing AdditionalProperties Endpoints", () => {
     });
   });
 
-  describe("SpreadRecordDiscriminatedUnion", () => {
+  /**
+   * Deprecated @discriminator in unions
+   */
+  describe.skip("SpreadRecordDiscriminatedUnion", () => {
     const client = new SpreadRecordDiscriminatedUnionClient(clientOptions);
     const expected: SpreadRecordForDiscriminatedUnion = {
       name: "abc",