Revert "Add validator to prevent discriminator and encodedname used together" (#3852)

Reverts microsoft/typespec#3763

This is actually a pattern used for things like `@odata.kind` and would
need more discussion to disallow

.chronus/changes/discriminator-encodedname-2024-6-8-16-24-7.md

@@ -1,8 +0,0 @@
----
-# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
-changeKind: feature
-packages:
-  - "@typespec/compiler"
----
-
-Add validator to prevent discriminator and encodedname used together

.github/workflows/consistency.yml

@@ -35,7 +35,8 @@ jobs:
         if: |
           !startsWith(github.head_ref, 'publish/') &&
           !startsWith(github.head_ref, 'dependabot/') &&
-          !startsWith(github.head_ref, 'backmerge/')
+          !startsWith(github.head_ref, 'backmerge/') &&
+          !startsWith(github.head_ref, 'revert-')
 
   # Validate spell check
   spellcheck:

docs/release-notes/release-2024-07-16.md

@@ -86,7 +86,6 @@ In this example, the `Child` model overrides the `example` property from the `Ba
 ### @typespec/compiler
 
 - [#3699](https://github.com/microsoft/typespec/pull/3699) Moved compiler dependencies to peer and dev for scaffolded projects.
-- [#3763](https://github.com/microsoft/typespec/pull/3763) Add validator to prevent discriminator and encodedname used together
 - [59daf90](https://github.com/microsoft/typespec/commit/59daf9054c709d3657e498b5f6dbe77492c98210) Add new `@example` and `@opExample` decorator to provide examples on types and operations.
 
   ```tsp

packages/compiler/src/core/messages.ts

@@ -876,12 +876,6 @@ const diagnostics = {
       duplicate: paramMessage`Same encoded name '${"name"}' is used for 2 members '${"mimeType"}'`,
     },
   },
-  "discriminator-encodedname": {
-    severity: "error",
-    messages: {
-      default: paramMessage`Discriminator property '${"discriminator"}' cannot be use an different encoded name.`,
-    },
-  },
 
   /**
    * Service

packages/compiler/src/core/program.ts

@@ -69,7 +69,7 @@ import {
   TypeSpecLibrary,
   TypeSpecScriptNode,
 } from "./types.js";
-import { validateIncompatibleEncodedNameAndDiscriminator } from "./validators/encoded-name-discriminator.js";
+
 export interface ProjectedProgram extends Program {
   projector: Projector;
 }
@@ -742,7 +742,6 @@ export async function compile(
   /** Run the compiler built-in validators */
   function runCompilerValidators() {
     validateEncodedNamesConflicts(program);
-    validateIncompatibleEncodedNameAndDiscriminator(program);
   }
 
   function validateRequiredImports() {

packages/compiler/src/core/validators/encoded-name-discriminator.ts

@@ -1,37 +0,0 @@
-import { getEncodedNames } from "../../lib/encoded-names.js";
-import { Discriminator, getDiscriminatedTypes } from "../intrinsic-type-state.js";
-import { reportDiagnostic } from "../messages.js";
-import type { Program } from "../program.js";
-import { Model } from "../types.js";
-
-/**
- * Validate you do not use `@encodedName` on a discriminator property.
- */
-export function validateIncompatibleEncodedNameAndDiscriminator(program: Program) {
-  for (const [type, discriminator] of getDiscriminatedTypes(program)) {
-    if (type.kind === "Model") {
-      validateModel(program, type, discriminator);
-      for (const child of type.derivedModels) {
-        validateModel(program, child, discriminator);
-      }
-    } else {
-      for (const variant of type.variants.values()) {
-        if (variant.type.kind === "Model") {
-          validateModel(program, variant.type, discriminator);
-        }
-      }
-    }
-  }
-}
-
-function validateModel(program: Program, type: Model, discriminator: Discriminator) {
-  const property = type.properties.get(discriminator.propertyName);
-  const names = property && getEncodedNames(program, property);
-  if (names && names?.size > 0) {
-    reportDiagnostic(program, {
-      code: "discriminator-encodedname",
-      target: type,
-      format: { discriminator: discriminator.propertyName },
-    });
-  }
-}

packages/compiler/src/lib/encoded-names.ts

@@ -39,13 +39,6 @@ export function $encodedName(
   existing.set(mimeType, name);
 }
 
-/**
- * @internal
- */
-export function getEncodedNames(program: Program, target: Type): Map<string, string> | undefined {
-  return program.stateMap(encodedNameKey).get(target);
-}
-
 function getEncodedName(program: Program, target: Type, mimeType: string): string | undefined {
   const mimeTypeObj = parseMimeType(mimeType);
   if (mimeTypeObj === undefined) {
@@ -54,7 +47,7 @@ function getEncodedName(program: Program, target: Type, mimeType: string): strin
   const resolvedMimeType = mimeTypeObj?.suffix
     ? `${mimeTypeObj.type}/${mimeTypeObj.suffix}`
     : mimeType;
-  return getEncodedNames(program, target)?.get(resolvedMimeType);
+  return program.stateMap(encodedNameKey).get(target)?.get(resolvedMimeType);
 }
 
 /**

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

@@ -1319,58 +1319,6 @@ describe("compiler: built-in decorators", () => {
       });
     });
 
-    describe("error when use on discriminator", () => {
-      it("emit error when use on base property", async () => {
-        const diagnostics = await runner.diagnose(`
-          @discriminator("kind")
-          model Cert {
-            @encodedName("application/json", "k")
-            kind: string;
-          }
-        `);
-
-        expectDiagnostics(diagnostics, {
-          code: "discriminator-encodedname",
-        });
-      });
-
-      it("emit error when use on derived model property", async () => {
-        const diagnostics = await runner.diagnose(`
-          @discriminator("kind")
-          model Base {
-            kind: string;
-          }
-
-          model Child extends Base {
-            @encodedName("application/json", "k")
-            kind: "child";
-          }
-        `);
-
-        expectDiagnostics(diagnostics, {
-          code: "discriminator-encodedname",
-        });
-      });
-
-      it("emit error when use on union variant property", async () => {
-        const diagnostics = await runner.diagnose(`
-          @discriminator("kind")
-          union Base {
-            child: Child
-          }
-
-          model Child {
-            @encodedName("application/json", "k")
-            kind: "child";
-          }
-        `);
-
-        expectDiagnostics(diagnostics, {
-          code: "discriminator-encodedname",
-        });
-      });
-    });
-
     it("resolve explicit encoded name", async () => {
       const { expireAt } = (await runner.compile(`
         model Cert {