fix(typescript-estree): allow writing to deprecated node properties

packages/typescript-estree/src/convert.ts

@@ -3319,23 +3319,30 @@ export class Converter {
     aliasKey: AliasKey,
     valueKey: ValueKey,
   ): Properties & Record<AliasKey, Properties[ValueKey]> {
-    let errored = false;
+    let warned = false;
 
     Object.defineProperty(node, aliasKey, {
+      configurable: true,
       get: this.options.suppressDeprecatedPropertyWarnings
         ? (): Properties[typeof valueKey] => node[valueKey]
         : (): Properties[typeof valueKey] => {
-            if (!this.options.suppressDeprecatedPropertyWarnings) {
-              if (!errored) {
-                // eslint-disable-next-line no-console
-                console.warn(
-                  `The '${aliasKey}' property is deprecated on ${node.type} nodes. Use '${valueKey}' instead. See https://typescript-eslint.io/linting/troubleshooting#the-key-property-is-deprecated-on-type-nodes-use-key-instead-warnings.`,
-                );
-                errored = true;
-              }
+            if (!warned) {
+              process.emitWarning(
+                `The '${aliasKey}' property is deprecated on ${node.type} nodes. Use '${valueKey}' instead. See https://typescript-eslint.io/linting/troubleshooting#the-key-property-is-deprecated-on-type-nodes-use-key-instead-warnings.`,
+                'DeprecationWarning',
+              );
+              warned = true;
             }
+
             return node[valueKey];
           },
+      set(value): void {
+        Object.defineProperty(node, aliasKey, {
+          enumerable: true,
+          writable: true,
+          value,
+        });
+      },
     });
 
     return node as Properties & Record<AliasKey, Properties[ValueKey]>;

packages/typescript-estree/tests/lib/convert.test.ts

@@ -7,6 +7,10 @@ import type { ConverterOptions } from '../../src/convert';
 import { Converter } from '../../src/convert';
 
 describe('convert', () => {
+  afterEach(() => {
+    jest.resetAllMocks();
+  });
+
   function convertCode(code: string): ts.SourceFile {
     return ts.createSourceFile(
       'text.ts',
@@ -268,7 +272,7 @@ describe('convert', () => {
 
   describe('suppressDeprecatedPropertyWarnings', () => {
     const getEsCallExpression = (
-      converterOptions: ConverterOptions,
+      converterOptions?: ConverterOptions,
     ): TSESTree.CallExpression => {
       const ast = convertCode(`callee<T>();`);
       const tsCallExpression = (ast.statements[0] as ts.ExpressionStatement)
@@ -285,22 +289,27 @@ describe('convert', () => {
       return maps.tsNodeToESTreeNodeMap.get(tsCallExpression);
     };
 
-    it('logs on a deprecated property access when suppressDeprecatedPropertyWarnings is false', () => {
-      const warn = jest.spyOn(console, 'warn').mockImplementation();
+    it('warns on a deprecated property access when suppressDeprecatedPropertyWarnings is false', () => {
+      const emitWarning = jest
+        .spyOn(process, 'emitWarning')
+        .mockImplementation();
       const esCallExpression = getEsCallExpression({
         suppressDeprecatedPropertyWarnings: false,
       });
 
       // eslint-disable-next-line deprecation/deprecation
       esCallExpression.typeParameters;
 
-      expect(warn).toHaveBeenCalledWith(
+      expect(emitWarning).toHaveBeenCalledWith(
         `The 'typeParameters' property is deprecated on CallExpression nodes. Use 'typeArguments' instead. See https://typescript-eslint.io/linting/troubleshooting#the-key-property-is-deprecated-on-type-nodes-use-key-instead-warnings.`,
+        'DeprecationWarning',
       );
     });
 
-    it('does not log on a subsequent deprecated property access when suppressDeprecatedPropertyWarnings is false', () => {
-      const warn = jest.spyOn(console, 'warn').mockImplementation();
+    it('does not warn on a subsequent deprecated property access when suppressDeprecatedPropertyWarnings is false', () => {
+      const emitWarning = jest
+        .spyOn(process, 'emitWarning')
+        .mockImplementation();
       const esCallExpression = getEsCallExpression({
         suppressDeprecatedPropertyWarnings: false,
       });
@@ -310,19 +319,38 @@ describe('convert', () => {
       esCallExpression.typeParameters;
       /* eslint-enable deprecation/deprecation */
 
-      expect(warn).toHaveBeenCalledTimes(1);
+      expect(emitWarning).toHaveBeenCalledTimes(1);
     });
 
-    it('does not log on a deprecated property access when suppressDeprecatedPropertyWarnings is true', () => {
-      const warn = jest.spyOn(console, 'warn').mockImplementation();
+    it('does not warn on a deprecated property access when suppressDeprecatedPropertyWarnings is true', () => {
+      const emitWarning = jest
+        .spyOn(process, 'emitWarning')
+        .mockImplementation();
       const esCallExpression = getEsCallExpression({
         suppressDeprecatedPropertyWarnings: true,
       });
 
       // eslint-disable-next-line deprecation/deprecation
       esCallExpression.typeParameters;
 
-      expect(warn).not.toHaveBeenCalled();
+      expect(emitWarning).not.toHaveBeenCalled();
+    });
+
+    it('does not allow enumeration of deprecated properties', () => {
+      const esCallExpression = getEsCallExpression();
+
+      expect(Object.keys(esCallExpression)).not.toContain('typeParameters');
+    });
+
+    it('allows writing to the deprecated property as a new enumerable value', () => {
+      const esCallExpression = getEsCallExpression();
+
+      // eslint-disable-next-line deprecation/deprecation
+      esCallExpression.typeParameters = undefined;
+
+      // eslint-disable-next-line deprecation/deprecation
+      expect(esCallExpression.typeParameters).toBeUndefined();
+      expect(Object.keys(esCallExpression)).toContain('typeParameters');
     });
   });
 });