fix: correct ESLint typings (#20122)

Pixel998 · web-flow · commit 861c6da2bd27 · 2025-09-23T23:24:37.000+02:00
* fix: correct `ESLint` typings

* add tests

* clarify `DeprecatedRuleUse.info` behavior
diff --git a/lib/types/index.d.ts b/lib/types/index.d.ts
@@ -1963,7 +1963,7 @@ export class ESLint {
 
 	calculateConfigForFile(filePath: string): Promise<any>;
 
-	findConfigFile(): Promise<string | undefined>;
+	findConfigFile(filePath?: string): Promise<string | undefined>;
 
 	isPathIgnored(filePath: string): Promise<boolean>;
 
@@ -2045,7 +2045,7 @@ export namespace ESLint {
 
 		// Autofix
 		fix?: boolean | ((message: Linter.LintMessage) => boolean) | undefined;
-		fixTypes?: FixType[] | undefined;
+		fixTypes?: FixType[] | null | undefined;
 
 		// Cache-related
 		cache?: boolean | undefined;
@@ -2079,7 +2079,7 @@ export namespace ESLint {
 
 		// Autofix
 		fix?: boolean | ((message: Linter.LintMessage) => boolean) | undefined;
-		fixTypes?: FixType[] | undefined;
+		fixTypes?: FixType[] | null | undefined;
 
 		// Cache-related
 		cache?: boolean | undefined;
@@ -2168,9 +2168,10 @@ export namespace ESLint {
 
 		/**
 		 * The raw deprecated info provided by the rule.
-		 * Unset if the rule's `meta.deprecated` property is a boolean.
+		 * - Undefined if the rule's `meta.deprecated` property is a boolean.
+		 * - Unset when using the legacy eslintrc configuration.
 		 */
-		info?: DeprecatedInfo;
+		info?: DeprecatedInfo | undefined;
 	}
 
 	/**
diff --git a/tests/lib/types/types.test.ts b/tests/lib/types/types.test.ts
@@ -1507,6 +1507,7 @@ linterWithEslintrcConfig.getRules();
 	eslint = new ESLint({ fix: true });
 	eslint = new ESLint({ fix: message => false });
 	eslint = new ESLint({ fixTypes: ["directive", "problem"] });
+	eslint = new ESLint({ fixTypes: null });
 	eslint = new ESLint({ flags: ["foo", "bar"] });
 	eslint = new ESLint({ globInputPaths: true });
 	eslint = new ESLint({ ignore: true });
@@ -1575,6 +1576,9 @@ linterWithEslintrcConfig.getRules();
 
 	eslint.calculateConfigForFile("./config.json");
 
+	eslint.findConfigFile("src/index.js");
+	eslint.findConfigFile();
+
 	eslint.isPathIgnored("./dist/index.js");
 
 	let formatterPromise: Promise<ESLint.Formatter>;
@@ -1655,6 +1659,7 @@ linterWithEslintrcConfig.getRules();
 	eslint = new LegacyESLint({ fix: true });
 	eslint = new LegacyESLint({ fix: message => false });
 	eslint = new LegacyESLint({ fixTypes: ["directive", "problem"] });
+	eslint = new LegacyESLint({ fixTypes: null });
 	eslint = new LegacyESLint({ flags: ["foo", "bar"] });
 	eslint = new LegacyESLint({ globInputPaths: true });
 	eslint = new LegacyESLint({ ignore: true });
@@ -1824,6 +1829,7 @@ for (const result of results) {
 	const deprecatedRule = result.usedDeprecatedRules[0];
 	deprecatedRule.ruleId = "foo";
 	deprecatedRule.replacedBy = ["bar"];
+	deprecatedRule.info = undefined;
 	deprecatedRule.info = {
 		message: "use bar instead",
 		replacedBy: [
