fix: handle undefined code field in oxlint diagnostics

.changeset/fix-missing-code-field.md

@@ -0,0 +1,5 @@
+---
+"@react-doctor/core": patch
+---
+
+Fix crash when oxlint diagnostic has no code field. Some diagnostics (like parse errors) omit the code field, causing parseRuleCode to throw "Cannot read properties of undefined (reading 'match')". parseRuleCode now returns { plugin: "unknown", rule: "unknown" } when code is missing.

packages/core/src/runners/oxlint/parse-output.ts

@@ -237,7 +237,8 @@ const resolveCleanedDiagnostic = (
   };
 };
 
-const parseRuleCode = (code: string): { plugin: string; rule: string } => {
+const parseRuleCode = (code: string | undefined): { plugin: string; rule: string } => {
+  if (!code) return { plugin: "unknown", rule: "unknown" };
   const match = code.match(/^(.+)\((.+)\)$/);
   if (!match) return { plugin: "unknown", rule: code };
   return { plugin: match[1].replace(/^eslint-plugin-/, ""), rule: match[2] };

packages/core/tests/oxlint-missing-code.test.ts

@@ -0,0 +1,100 @@
+import { describe, expect, it } from "vite-plus/test";
+import { parseOxlintOutput } from "../src/runners/oxlint/parse-output.js";
+import { buildProject } from "./helpers/oxlint-parse-harness.js";
+
+describe("parseOxlintOutput with missing code field", () => {
+  it("handles diagnostics with no code field without crashing", () => {
+    const stdout = JSON.stringify({
+      diagnostics: [
+        {
+          message: "Parse error: unexpected token",
+          severity: "error",
+          causes: [],
+          url: "",
+          help: "",
+          filename: "src/components/widget.tsx",
+          labels: [{ label: "", span: { offset: 0, length: 1, line: 12, column: 3 } }],
+          related: [],
+        },
+      ],
+      number_of_files: 1,
+      number_of_rules: 1,
+    });
+
+    expect(() => {
+      parseOxlintOutput(stdout, buildProject(), "/home/user/app");
+    }).not.toThrow();
+  });
+
+  it("handles diagnostics with undefined code field", () => {
+    const stdout = JSON.stringify({
+      diagnostics: [
+        {
+          message: "Parse error",
+          code: undefined,
+          severity: "error",
+          causes: [],
+          url: "",
+          help: "",
+          filename: "src/components/widget.tsx",
+          labels: [{ label: "", span: { offset: 0, length: 1, line: 12, column: 3 } }],
+          related: [],
+        },
+      ],
+      number_of_files: 1,
+      number_of_rules: 1,
+    });
+
+    expect(() => {
+      parseOxlintOutput(stdout, buildProject(), "/home/user/app");
+    }).not.toThrow();
+  });
+
+  it("handles diagnostics with null code field", () => {
+    const stdout = JSON.stringify({
+      diagnostics: [
+        {
+          message: "Parse error",
+          code: null,
+          severity: "error",
+          causes: [],
+          url: "",
+          help: "",
+          filename: "src/components/widget.tsx",
+          labels: [{ label: "", span: { offset: 0, length: 1, line: 12, column: 3 } }],
+          related: [],
+        },
+      ],
+      number_of_files: 1,
+      number_of_rules: 1,
+    });
+
+    expect(() => {
+      parseOxlintOutput(stdout, buildProject(), "/home/user/app");
+    }).not.toThrow();
+  });
+
+  it("handles diagnostics with empty string code field", () => {
+    const stdout = JSON.stringify({
+      diagnostics: [
+        {
+          message: "Parse error",
+          code: "",
+          severity: "error",
+          causes: [],
+          url: "",
+          help: "",
+          filename: "src/components/widget.tsx",
+          labels: [{ label: "", span: { offset: 0, length: 1, line: 12, column: 3 } }],
+          related: [],
+        },
+      ],
+      number_of_files: 1,
+      number_of_rules: 1,
+    });
+
+    expect(() => {
+      parseOxlintOutput(stdout, buildProject(), "/home/user/app");
+    }).not.toThrow();
+  });
+});

packages/react-doctor/tests/regressions/scan-resilience.test.ts

@@ -19,6 +19,9 @@
  *          exports — older plugin versions can lack newer compiler rules,
  *          so React Compiler users would otherwise hit
  *          "Rule 'void-use-memo' not found in plugin 'react-hooks-js'".
+ *   #1635 — parseRuleCode must handle diagnostics with no code field —
+ *          some oxlint diagnostics (like parse errors) omit the code field,
+ *          causing "Cannot read properties of undefined (reading 'match')".
  */
 
 import { spawnSync } from "node:child_process";