Before You File a Bug Report Please Confirm You Have Done The Following...

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have searched for related issues and found none that matched my issue.
• I have read the FAQ and my problem is not listed.

Relevant Package

typescript-estree

ESLint Config

import tseslint from "typescript-eslint";

export default tseslint.config(tseslint.configs.base, {
	files: ["**/*.ts"],
	languageOptions: {
		parserOptions: {
			projectService: true,
			tsconfigRootDir: import.meta.dirname,
		},
	},
	rules: {
		"@typescript-eslint/no-floating-promises": "error",
	},
});

Expected Result

Internally, inferSingleRun should return true when we're in single-run mode. Executing this config with something like npx eslint . should be determined to be in single-run mode.

Actual Result

singleRun is always inferred to be false right now, because of:

Additional Info

This doesn't generally have any impact on runtime performance right now. The project service doesn't generally use any single-run optimizations in single-run mode. But:

• It's confusing internally to see singleRun set to false
• There'll likely eventually be some optimizations, such as the caching TS system host mentioned in ⚡ Performance: Project service doesn't cache all fs.statSync microsoft/TypeScript#59338 (comment)

We should also investigate whether the options?.extraFileExtensions?.length check can be bypassed with options.projectService per #9504:

Versions