feat: support only applying fix-later with --fix-type=directive (#5)

README.md

@@ -96,6 +96,10 @@ In your ESLint config:
 
 	This approach prevents errors from slipping through while accommodating "fix later" notes.
 
+### Suppressing auto-fixable errors (ESLint v8+)
+
+Pass in the [`--fix-type=directive`](https://eslint.org/docs/latest/use/command-line-interface#--fix-type) flag to ESLint to only apply the fix-later auto-fix.
+
 ## Options
 
 ### includeWarnings

package.json

@@ -58,7 +58,7 @@
 		"find-up-simple": "^1.0.0",
 		"fs-fixture": "^2.4.0",
 		"ignore": "^5.3.1",
-		"lintroll": "^1.7.1",
+		"lintroll": "^1.8.1",
 		"manten": "^1.3.0",
 		"outdent": "^0.8.0",
 		"pkgroll": "^2.4.1",

src/rules/fix-later/fix-later.ts

@@ -68,7 +68,12 @@ const suppressFileErrors = (
 
 	// If applying fix, only suppress errors that can't be fixed
 	if (fix) {
-		processMessages = processMessages.filter(message => !message.fix);
+		processMessages = processMessages.filter(message => (
+			!message.fix
+
+			// Filter that applies `--fix-type`
+			|| (typeof fix === 'function' && !fix(message))
+		));
 	} else {
 		const suppressableMessages = processMessages.filter(message => !message.fix);
 
@@ -179,24 +184,32 @@ const suppressFileErrors = (
 			comments.push(`<!-- eslint-enable ${rulesToDisable} -->`);
 		}
 
+		const line = Number(key);
 		const lineStartIndex = sourceCode.getIndexFromLoc({
-			line: Number(key),
+			line,
 			column: 0,
 		});
 
 		const comment = comments.join('\n');
+		const insertCommentAbove = (
+			ruleOptions.insertDisableComment === 'above-line'
+			|| groupedMessages.start.length > 0
+			|| groupedMessages.end.length > 0
+		);
 		messages.push({
-			ruleId,
+			/**
+			 * Not specifiying a ruleId allows us to only apply this fix
+			 * when --fix-type=directive is passed in
+			 *
+			 * https://github.com/eslint/eslint/blob/v8.0.0/lib/cli-engine/cli-engine.js#L342-L344
+			 */
+			ruleId: null,
 			severity: ruleSeverity,
-			message: 'Suppressing errors',
-			line: 0,
+			message: `fix-later: insert eslint comment on L${line + (insertCommentAbove ? 1 : 0)}`,
+			line,
 			column: 0,
 			fix: (
-				(
-					ruleOptions.insertDisableComment === 'above-line'
-					|| groupedMessages.start.length > 0
-					|| groupedMessages.end.length > 0
-				)
+				insertCommentAbove
 					? insertCommentAboveLine(
 						code,
 						lineStartIndex,

src/rules/fix-later/index.ts

@@ -31,7 +31,6 @@ export const fixLater = {
 				additionalProperties: false,
 			},
 		],
-		type: 'problem',
 	},
 	create: (context) => {
 		const options = normalizeOptions(context.options[0]);

src/rules/fix-later/utils/vue.ts

@@ -2,7 +2,7 @@ import type { AST } from 'vue-eslint-parser';
 
 const safeRequire = <Type>(id: string) => {
 	try {
-		// eslint-disable-next-line import-x/no-dynamic-require, @typescript-eslint/no-var-requires
+		// eslint-disable-next-line import-x/no-dynamic-require, @typescript-eslint/no-require-imports
 		return require(id) as Type;
 	} catch {
 		return null;

tests/specs/basic-usage.ts

@@ -249,6 +249,41 @@ export default testSuite(({ describe }, eslintPath: string) => {
 			});
 		});
 
+		if (eslintPath.includes('eslint8')) {
+			test('apply fix-only with --fix-type=directive', async () => {
+				const content = outdent`
+				var foo = () => 0
+				`;
+				const result = await eslint(eslintPath, {
+					config: {
+						parserOptions: {
+							ecmaVersion: 2021,
+						},
+						rules: {
+							'fix-later/fix-later': ['warn', {
+								insertDisableComment: 'above-line',
+							}],
+							'arrow-body-style': ['error', 'always'],
+						},
+					},
+					code: {
+						content,
+					},
+					fix: true,
+
+					// Only applies fix-later and doesn't auto-fix the arrow-body-style
+					fixType: 'directive',
+				});
+
+				expect(result.output).toBe(
+					outdent`
+					// eslint-disable-next-line arrow-body-style -- Fix later
+					var foo = () => 0
+					`,
+				);
+			});
+		}
+
 		test('inherits indentation without mixing tabs + spaces', async () => {
 			const content = outdent`
 			if (true) {

tests/utils/eslint.ts

@@ -15,6 +15,7 @@ type Options = {
 	code: string | StdIn;
 	cwd?: string;
 	fix?: boolean;
+	fixType?: 'directive';
 };
 
 export const eslint = async (
@@ -24,6 +25,7 @@ export const eslint = async (
 		config: configRaw,
 		code,
 		fix,
+		fixType,
 	}: Options,
 ) => {
 	await installSelfPackage(cwd);
@@ -45,6 +47,9 @@ export const eslint = async (
 
 	if (fix) {
 		eslintArgs.push('--fix-dry-run');
+		if (fixType) {
+			eslintArgs.push(`--fix-type=${fixType}`);
+		}
 	}
 
 	if (typeof code === 'object') {