Merge remote-tracking branch 'origin/farm/38b90f8c/fix-biome-json-reporter-schema'

packages/coding-agent/CHANGELOG.md

@@ -66,6 +66,10 @@
 - Fixed `/vibe` cancellation leaving an in-flight model turn unaware that Vibe mode and its tools were removed ([#8326](https://github.com/can1357/oh-my-pi/issues/8326)).
 - Fixed empty local-model stops lingering on the persisted active branch after retries; discarded turns now durably select their parent, preserve safe metadata children, and cannot resurface after reload or a mid-retry process kill. ([#5179](https://github.com/can1357/oh-my-pi/issues/5179))
 
+### Fixed
+
+- Fixed the Biome linter client silently dropping every diagnostic because `#parseJsonOutput` expected an outdated `--reporter=json` schema (`location.path.file`, byte-offset `span`, `description`); it now reads Biome 2.x's string `location.path`, 1-indexed `location.start`/`location.end`, and `message`, and warns when a non-empty diagnostics array has no recognizable location ([#8694](https://github.com/can1357/oh-my-pi/issues/8694)).
+
 ## [17.3.4] - 2026-08-14
 
 ### Changed

packages/coding-agent/src/lsp/clients/biome-client.ts

@@ -14,14 +14,21 @@ interface BiomeJsonOutput {
 	diagnostics: BiomeDiagnostic[];
 }
 
+/**
+ * A single diagnostic from Biome's `--reporter=json` output (Biome 2.x).
+ *
+ * Positions are 1-indexed `{ line, column }` pairs; the path is a plain string
+ * relative to the CLI's cwd. Older releases used byte-offset `span`s, which
+ * this client no longer parses.
+ */
 interface BiomeDiagnostic {
 	category: string; // e.g., "lint/correctness/noUnusedVariables"
-	severity: "error" | "warning" | "info" | "hint";
-	description: string;
+	severity: string; // "error" | "warning" | "info" | "hint"
+	message: string;
 	location?: {
-		path?: { file: string };
-		span?: [number, number]; // [startOffset, endOffset] in bytes
-		sourceCode?: string;
+		path?: string;
+		start?: { line: number; column: number };
+		end?: { line: number; column: number };
 	};
 }
 
@@ -29,43 +36,6 @@ interface BiomeDiagnostic {
 // Helpers
 // =============================================================================
 
-/**
- * Convert byte offsets to line:column positions in a single pass over the source.
- */
-function offsetsToPositions(source: string, offsets: number[]): Map<number, { line: number; column: number }> {
-	const sorted = [...new Set(offsets)].sort((a, b) => a - b);
-	const result = new Map<number, { line: number; column: number }>();
-	let line = 1;
-	let column = 1;
-	let byteIndex = 0;
-	let next = 0;
-
-	for (const ch of source) {
-		if (next >= sorted.length) break;
-		const cp = ch.codePointAt(0) as number;
-		const byteLen = cp < 0x80 ? 1 : cp < 0x800 ? 2 : cp < 0x10000 ? 3 : 4;
-		while (next < sorted.length && byteIndex + byteLen > sorted[next]) {
-			result.set(sorted[next], { line, column });
-			next++;
-		}
-		if (ch === "\n") {
-			line++;
-			column = 1;
-		} else {
-			column++;
-		}
-		byteIndex += byteLen;
-	}
-
-	// Offsets at or past end-of-file map to the final position.
-	while (next < sorted.length) {
-		result.set(sorted[next], { line, column });
-		next++;
-	}
-
-	return result;
-}
-
 /**
  * Parse Biome severity to LSP DiagnosticSeverity.
  */
@@ -176,8 +146,6 @@ export class BiomeClient implements LinterClient {
 	 * Parse Biome's JSON output into LSP Diagnostics.
 	 */
 	#parseJsonOutput(jsonOutput: string, targetFile: string): Diagnostic[] {
-		const diagnostics: Diagnostic[] = [];
-
 		let parsed: BiomeJsonOutput;
 		try {
 			parsed = JSON.parse(jsonOutput);
@@ -186,61 +154,36 @@ export class BiomeClient implements LinterClient {
 				cwd: this.cwd,
 				file: targetFile,
 			});
-			return diagnostics;
+			return [];
 		}
 
+		const emitted = parsed.diagnostics ?? [];
 		const target = path.resolve(targetFile);
-		const relevant: BiomeDiagnostic[] = [];
-		// Batch all span offsets per source text so each source is scanned once
-		// instead of twice per diagnostic.
-		const offsetsBySource = new Map<string, number[]>();
-		for (const diag of parsed.diagnostics ?? []) {
+		const diagnostics: Diagnostic[] = [];
+		// Biome's JSON reporter is experimental and may reshape its output in
+		// patch releases. Track whether any diagnostic carried a usable location
+		// so a schema drift surfaces as a warning instead of a silent empty list.
+		let sawUsableLocation = false;
+
+		for (const diag of emitted) {
 			const location = diag.location;
-			if (!location?.path?.file) continue;
+			const filePath = location?.path;
+			if (!filePath) continue;
+			sawUsableLocation = true;
 
-			// Resolve file path
-			const diagFile = path.isAbsolute(location.path.file)
-				? location.path.file
-				: path.join(this.cwd, location.path.file);
+			// Biome reports paths relative to its cwd.
+			const diagFile = path.isAbsolute(filePath) ? filePath : path.join(this.cwd, filePath);
 
-			// Only include diagnostics for the target file
-			if (path.resolve(diagFile) !== target) {
-				continue;
-			}
+			// Only include diagnostics for the target file.
+			if (path.resolve(diagFile) !== target) continue;
 
-			relevant.push(diag);
-			if (location.span && location.sourceCode) {
-				const offsets = offsetsBySource.get(location.sourceCode);
-				if (offsets) offsets.push(location.span[0], location.span[1]);
-				else offsetsBySource.set(location.sourceCode, [location.span[0], location.span[1]]);
-			}
-		}
-
-		const positionsBySource = new Map<string, Map<number, { line: number; column: number }>>();
-		for (const [source, offsets] of offsetsBySource) {
-			positionsBySource.set(source, offsetsToPositions(source, offsets));
-		}
-
-		for (const diag of relevant) {
-			const location = diag.location;
-			let startLine = 1;
-			let startColumn = 1;
-			let endLine = 1;
-			let endColumn = 1;
-
-			if (location?.span && location.sourceCode) {
-				const positions = positionsBySource.get(location.sourceCode);
-				const startPos = positions?.get(location.span[0]);
-				const endPos = positions?.get(location.span[1]);
-				if (startPos) {
-					startLine = startPos.line;
-					startColumn = startPos.column;
-				}
-				if (endPos) {
-					endLine = endPos.line;
-					endColumn = endPos.column;
-				}
-			}
+			// Biome positions are 1-indexed; LSP ranges are 0-indexed.
+			const start = location.start;
+			const end = location.end ?? start;
+			const startLine = start?.line ?? 1;
+			const startColumn = start?.column ?? 1;
+			const endLine = end?.line ?? startLine;
+			const endColumn = end?.column ?? startColumn;
 
 			diagnostics.push({
 				range: {
@@ -248,12 +191,23 @@ export class BiomeClient implements LinterClient {
 					end: { line: endLine - 1, character: endColumn - 1 },
 				},
 				severity: parseSeverity(diag.severity),
-				message: diag.description,
+				message: diag.message,
 				source: "biome",
 				code: diag.category,
 			});
 		}
 
+		// Non-empty output whose diagnostics all lacked a recognizable location
+		// means the reporter schema changed out from under us — warn loudly
+		// instead of masking the regression as "no lint issues".
+		if (emitted.length > 0 && !sawUsableLocation) {
+			warnBiomeOnce(
+				`schema:${this.cwd}`,
+				"Biome diagnostics had no recognizable location; reporter schema may have changed",
+				{ cwd: this.cwd, file: targetFile, count: emitted.length },
+			);
+		}
+
 		return diagnostics;
 	}
 

packages/coding-agent/test/biome-client.test.ts

@@ -130,3 +130,44 @@ describe("BiomeClient format", () => {
 		expect(result).toBe(content);
 	});
 });
+
+describe("BiomeClient lint", () => {
+	test("surfaces Biome 2.x --reporter=json diagnostics", async () => {
+		const tempDir = await makeTempDir();
+		await Bun.write(
+			path.join(tempDir, "biome.json"),
+			`${JSON.stringify({ linter: { enabled: true, rules: { recommended: true } } })}\n`,
+		);
+		const targetFile = path.join(tempDir, "lint-me.ts");
+		// `x == 2` triggers lint/suspicious/noDoubleEquals (a recommended rule).
+		await Bun.write(targetFile, "const x: number = 1;\nif (x == 2) {\n}\n");
+
+		const diagnostics = await new BiomeClient(biomeConfig(repoBiome), tempDir).lint(targetFile);
+
+		const doubleEquals = diagnostics.find(d => d.code === "lint/suspicious/noDoubleEquals");
+		expect(doubleEquals).toBeDefined();
+		expect(doubleEquals?.source).toBe("biome");
+		expect(doubleEquals?.severity).toBe(1);
+		expect(doubleEquals?.message).toContain("==");
+		// Biome reports `==` at line 2, columns 7-9 (1-indexed); LSP ranges are
+		// 0-indexed, so the mapping must land on line 1, characters 6-8.
+		expect(doubleEquals?.range).toEqual({
+			start: { line: 1, character: 6 },
+			end: { line: 1, character: 8 },
+		});
+	});
+
+	test("returns no diagnostics for a clean file", async () => {
+		const tempDir = await makeTempDir();
+		await Bun.write(
+			path.join(tempDir, "biome.json"),
+			`${JSON.stringify({ linter: { enabled: true, rules: { recommended: true } } })}\n`,
+		);
+		const targetFile = path.join(tempDir, "clean.ts");
+		await Bun.write(targetFile, "export const value = 1;\n");
+
+		const diagnostics = await new BiomeClient(biomeConfig(repoBiome), tempDir).lint(targetFile);
+
+		expect(diagnostics).toEqual([]);
+	});
+});