feat(build-tools): add Biome 2.x configuration reader #25969

tylerbutler · 2025-12-03T04:16:27Z

Description

Biome 2.x changed configuration format from separate include/ignore fields to a unified includes field with negation patterns (e.g., ["**", "!node_modules/**"]). This adds support for the new format so fluid-build can correctly determine file scope for caching.

New files:

biome2ConfigTypes.d.ts - Type definitions for Biome 2.x config format (including root field)
biome2Config.ts - Reader that parses unified includes field with negation support
biomeVersion.ts - Version detection from package.json or CLI
biomeConfigUtils.ts - Shared utilities for config loading and extends resolution

Changes to biomeConfig.ts:

BiomeConfigReaderInterface - Common interface for both readers
createBiomeConfigReader() - Factory with auto-detection
Refactored to use shared utilities from biomeConfigUtils.ts

Key features:

Supports the root field for automatic parent config discovery (walks up directory tree until root: true is found)
Handles both explicit extends declarations and automatic parent config merging
Parses unified includes field and separates include/ignore patterns
Supports combined extends + find-up: root config can extend another config, and child configs inherit everything through find-up

// Auto-detects Biome version and uses appropriate reader
const reader = await createBiomeConfigReader(packageDir, gitRepo);
const files = reader.formattedFiles;

// Or force a specific version
const reader2x = await createBiomeConfigReader(packageDir, gitRepo, 2);

Usage:
Import directly from source modules:

import { Biome2ConfigReader, loadBiome2Config } from "./biome2Config";
import { detectBiomeVersion, BiomeMajorVersion } from "./biomeVersion";

Reviewer Guidance

Version detection tries package.json first (faster), falls back to CLI
Both readers share BiomeConfigReaderInterface for interoperability
Shared utilities in biomeConfigUtils.ts reduce code duplication between 1.x and 2.x implementations:
- loadRawBiomeConfigFile<T>() - Generic JSON5 config loading
- resolveExtendsChainGeneric<T>() - Shared extends chain resolution with optional includeConfigPath parameter
Test data uses .jsonc extension (not biome.jsonc) to avoid Biome 1.x schema validation errors during checks
Tests include multi-level extends scenarios (e.g., pkg-b/config.jsonc → pkg-a/config.jsonc → baseconfig.jsonc) to verify config inheritance chains work correctly
Tests include nested configs WITHOUT extends (root: true/root: false) to verify automatic parent config discovery and merging
Tests cover combined extends AND find-up: root config extends baseconfig, child config uses find-up and inherits settings from both root and base

… interface Co-authored-by: tylerbutler <[email protected]>

… remove package-lock.json Co-authored-by: tylerbutler <[email protected]>

…dd nested extends tests Co-authored-by: tylerbutler <[email protected]>

…igs without extends Co-authored-by: tylerbutler <[email protected]>

Co-authored-by: tylerbutler <[email protected]>

… + find-up Co-authored-by: tylerbutler <[email protected]>

…hift performance Co-authored-by: tylerbutler <[email protected]>

build-tools/packages/build-tools/package.json

…ing logic Co-authored-by: tylerbutler <[email protected]>

Co-authored-by: tylerbutler <[email protected]>

…consolidate getClosestBiomeConfigPath Co-authored-by: tylerbutler <[email protected]>

Co-authored-by: tylerbutler <[email protected]>

… in Biome 2.x Co-authored-by: tylerbutler <[email protected]>

…patterns Co-authored-by: tylerbutler <[email protected]>

tylerbutler · 2025-12-04T00:25:24Z

build-tools/packages/build-tools/package.json

 		"eslint:fix": "eslint --format stylish src --fix --fix-type problem,suggestion,layout",
 		"format": "npm run format:biome",
 		"format:biome": "biome check --write .",
+		"json-schema-to-typescript:biome2ConfigTypes": "json2ts --input node_modules/biome2/configuration_schema.json --output src/common/biome2ConfigTypes.d.ts",


This won't work until we update to biome 2. I tried adding it with an npm alias but that cause v2 to get triggered when running format.

Copilot

Pull request overview

This PR adds support for Biome 2.x configuration format to the build tools, enabling fluid-build to correctly determine file scope for caching when Biome 2.x is used. The implementation introduces version detection, a new config reader for the unified includes field syntax with negation patterns, and shared utilities to reduce code duplication between Biome 1.x and 2.x implementations.

Key changes:

Automatic version detection from package.json or CLI with fallback to Biome 1.x
Support for Biome 2.x's unified includes field with negation patterns and re-inclusion support
Automatic parent config discovery via root field and directory tree walking
Refactored shared utilities for config loading and extends resolution

Reviewed changes

Copilot reviewed 21 out of 22 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
`src/common/biomeVersion.ts`	New file implementing Biome version detection from package.json and CLI
`src/common/biomeConfigUtils.ts`	New file with shared utilities for config loading, extends resolution, and file filtering
`src/common/biome2Config.ts`	New file implementing Biome 2.x config reader with unified includes field support
`src/common/biome2ConfigTypes.d.ts`	Auto-generated TypeScript definitions for Biome 2.x configuration schema
`src/common/biomeConfig.ts`	Refactored to use shared utilities, added BiomeConfigReader interface and createBiomeConfigReader factory
`src/fluidBuild/tasks/leaf/biomeTasks.ts`	Updated to use createBiomeConfigReader for automatic version detection
`src/test/biomeConfig.test.ts`	Updated to use renamed BiomeConfigReaderV1 class
`src/test/biome2Config.test.ts`	New comprehensive test suite for Biome 2.x functionality
`src/test/data/biome2/*`	New test data files for Biome 2.x config scenarios
`package.json`	Added script for generating biome2ConfigTypes (references non-existent package)

Copilot · 2025-12-04T00:57:28Z

build-tools/packages/build-tools/src/common/biome2Config.ts

+
+/**
+ * Loads a Biome 2.x configuration file _without_ following any 'extends' values. You probably want to use
+ * {@link loadBiome2Configs} instead of this function.


The docstring references {@link loadBiome2Configs} (with an 's'), but the actual function is named loadBiome2Config (without the 's'). This should be corrected to {@link loadBiome2Config}.

Suggested change

* {@link loadBiome2Configs} instead of this function.

* {@link getAllBiome2ConfigPaths} instead of this function.

Copilot · 2025-12-04T00:57:28Z

build-tools/packages/build-tools/src/common/biomeVersion.ts

+export function detectBiomeVersionFromCli(cwd?: string): BiomeVersionInfo | undefined {
+	try {
+		const output = execSync("npx biome --version", {
+			cwd,
+			encoding: "utf8",
+			stdio: ["pipe", "pipe", "pipe"],
+		});
+
+		// Output format is "Version: X.Y.Z" or just "X.Y.Z"
+		const versionMatch = output.match(/(\d+\.\d+\.\d+)/);
+		if (versionMatch) {
+			const version = versionMatch[1];
+			const major = semver.major(version);
+			if (major === 1 || major === 2) {
+				return {
+					version,
+					majorVersion: major as BiomeMajorVersion,
+				};
+			}
+		}
+	} catch {
+		// Biome CLI not available or failed
+	}
+	return undefined;
+}
+
+/**
+ * Detects the Biome version by reading the package.json of the @biomejs/biome package.
+ *
+ * @param startDir - The directory to start searching from. Will look for node_modules/@biomejs/biome/package.json.
+ * @returns The Biome version information, or undefined if the package is not found.
+ */
+export async function detectBiomeVersionFromPackage(
+	startDir: string,
+): Promise<BiomeVersionInfo | undefined> {
+	// Try to find the biome package.json by walking up the directory tree
+	let currentDir = startDir;
+	const root = path.parse(currentDir).root;
+
+	while (currentDir !== root) {
+		const biomePkgPath = path.join(
+			currentDir,
+			"node_modules",
+			"@biomejs",
+			"biome",
+			"package.json",
+		);
+		try {
+			const content = await readFile(biomePkgPath, "utf8");
+			const pkg = JSON.parse(content) as { version?: string };
+			if (pkg.version) {
+				const major = semver.major(pkg.version);
+				if (major === 1 || major === 2) {
+					return {
+						version: pkg.version,
+						majorVersion: major as BiomeMajorVersion,
+					};
+				}
+			}
+		} catch {
+			// Package not found at this level, continue searching
+		}
+		currentDir = path.dirname(currentDir);
+	}
+
+	return undefined;
+}
+
+/**
+ * Detects the Biome version, trying multiple methods:
+ * 1. First, try to read the version from the installed @biomejs/biome package
+ * 2. Fall back to running the Biome CLI
+ *
+ * @param startDir - The directory to start searching from.
+ * @returns The Biome version information, or undefined if Biome cannot be detected.
+ */
+export async function detectBiomeVersion(
+	startDir: string,
+): Promise<BiomeVersionInfo | undefined> {
+	// Try package.json first (faster and more reliable)
+	const fromPackage = await detectBiomeVersionFromPackage(startDir);
+	if (fromPackage) {
+		return fromPackage;
+	}
+
+	// Fall back to CLI detection
+	return detectBiomeVersionFromCli(startDir);
+}


The version detection functions (detectBiomeVersion, detectBiomeVersionFromPackage, detectBiomeVersionFromCli) lack test coverage. These functions contain logic that could fail in various ways (e.g., package.json not found, CLI not available, invalid version format) and would benefit from unit tests.

Consider adding tests that cover:

Successful version detection from package.json

Successful version detection from CLI

Fallback behavior when package.json method fails

Handling of invalid version strings

Behavior when Biome is not installed

Copilot · 2025-12-04T00:57:28Z

build-tools/packages/build-tools/src/common/biomeConfig.ts

+export async function createBiomeConfigReader(
+	directoryOrConfigFile: string,
+	gitRepo: GitRepo,
+	forceVersion?: BiomeMajorVersion,
+): Promise<BiomeConfigReader> {
+	let majorVersion: BiomeMajorVersion;
+
+	if (forceVersion !== undefined) {
+		majorVersion = forceVersion;
+	} else {
+		// Auto-detect the Biome version
+		const versionInfo = await detectBiomeVersion(directoryOrConfigFile);
+		majorVersion = versionInfo?.majorVersion ?? 1; // Default to 1.x if detection fails
 	}
+
+	if (majorVersion === 2) {
+		return Biome2ConfigReader.create(directoryOrConfigFile, gitRepo);
+	}
+
+	// Default to Biome 1.x reader
+	return BiomeConfigReaderV1.create(directoryOrConfigFile, gitRepo);
 }


The createBiomeConfigReader factory function lacks test coverage. This is a key new API that automatically detects the Biome version and returns the appropriate reader. Tests should verify:

Correct reader selection based on detected version (1.x vs 2.x)

Behavior when version detection fails (should default to 1.x)

Force version parameter override functionality

Integration with both BiomeConfigReaderV1 and Biome2ConfigReader

Copilot AI and others added 8 commits December 3, 2025 00:09

Initial plan

04f754e

Add Biome 2.x configuration reader with version detection and unified…

7258553

… interface Co-authored-by: tylerbutler <[email protected]>

Fix double-prefixing of glob patterns that already start with **/ and…

3054c4b

… remove package-lock.json Co-authored-by: tylerbutler <[email protected]>

Address review feedback: remove re-exports, remove unused function, a…

e0460db

…dd nested extends tests Co-authored-by: tylerbutler <[email protected]>

Add root field support for Biome 2.x config and tests for nested conf…

f928ee0

…igs without extends Co-authored-by: tylerbutler <[email protected]>

Address code review: improve docstrings and simplify test assertion

e25bf13

Co-authored-by: tylerbutler <[email protected]>

Add code sharing for extends resolution and test for combined extends…

8b6e276

… + find-up Co-authored-by: tylerbutler <[email protected]>

Improve code review feedback: add includeConfigPath param and fix uns…

2ff05a2

…hift performance Co-authored-by: tylerbutler <[email protected]>

tylerbutler changed the title ~~Copilot/update biomeconfigreader for 2 x~~ feat(build-tools): add Biome 2.x configuration reader Dec 3, 2025

tylerbutler commented Dec 3, 2025

View reviewed changes

build-tools/packages/build-tools/package.json Outdated Show resolved Hide resolved

tylerbutler and others added 15 commits December 3, 2025 12:42

use json schema to generate types

07bfffa

type fixes

80ee3d7

Merge branch 'main' into copilot/update-biomeconfigreader-for-2-x

a02357c

Address review feedback: add stopAt param, improve docs, share filter…

29cb8bc

…ing logic Co-authored-by: tylerbutler <[email protected]>

Clarify stopAt param documentation in findParentBiome2Configs

872b1ec

Co-authored-by: tylerbutler <[email protected]>

Rename class to BiomeConfigReaderV1, interface to BiomeConfigReader, …

fa2c614

…consolidate getClosestBiomeConfigPath Co-authored-by: tylerbutler <[email protected]>

Use createBiomeConfigReader factory in BiomeTask for auto-detection

ac756d9

Co-authored-by: tylerbutler <[email protected]>

Document globstar limitation and add tests for negation pattern ordering

c1bd1e8

Co-authored-by: tylerbutler <[email protected]>

Implement ordered pattern processing for correct re-inclusion support…

e9ef09d

… in Biome 2.x Co-authored-by: tylerbutler <[email protected]>

Fix re-inclusion logic: use multimatch instead of ignore for include …

514c658

…patterns Co-authored-by: tylerbutler <[email protected]>

Merge branch 'main' into copilot/update-biomeconfigreader-for-2-x

00ea3ff

Merge branch 'main' into copilot/update-biomeconfigreader-for-2-x

a47ecf0

policy

5e95bd8

fixes

cee35e8

unused var

e9f11a5

tylerbutler commented Dec 4, 2025

View reviewed changes

tylerbutler marked this pull request as ready for review December 4, 2025 00:33

tylerbutler requested review from a team and Copilot December 4, 2025 00:51

Copilot started reviewing on behalf of tylerbutler December 4, 2025 00:52 View session

Copilot finished reviewing on behalf of tylerbutler December 4, 2025 00:56

Copilot AI reviewed Dec 4, 2025

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feat(build-tools): add Biome 2.x configuration reader #25969

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	* {@link loadBiome2Configs} instead of this function.
	* {@link getAllBiome2ConfigPaths} instead of this function.

feat(build-tools): add Biome 2.x configuration reader #25969

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feat(build-tools): add Biome 2.x configuration reader #25969

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tylerbutler commented Dec 3, 2025

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