feat: Provide helpful error message for nullish configs (#18357)

* feat: Provide helpful error message for nullish configs fixes #18259 * Update lib/config/flat-config-array.js Co-authored-by: Francesco Trotta <[email protected]> * Update lib/config/flat-config-array.js Co-authored-by: Francesco Trotta <[email protected]> --------- Co-authored-by: Francesco Trotta <[email protected]>
eslint · Apr 19, 2024 · 03068f1 · 03068f1
1 parent 50d406d
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diff --git a/lib/config/flat-config-array.js b/lib/config/flat-config-array.js
@@ -79,7 +79,53 @@ function getObjectId(object) {
  return name;
 }
 
+/**
+ * Wraps a config error with details about where the error occurred.
+ * @param {Error} error The original error.
+ * @param {number} originalLength The original length of the config array.
+ * @param {number} baseLength The length of the base config.
+ * @returns {TypeError} The new error with details.
+ */
+function wrapConfigErrorWithDetails(error, originalLength, baseLength) {
+
+ let location = "user-defined";
+ let configIndex = error.index;
+
+ /*
+ * A config array is set up in this order:
+ * 1. Base config
+ * 2. Original configs
+ * 3. User-defined configs
+ * 4. CLI-defined configs
+ *
+ * So we need to adjust the index to account for the base config.
+ *
+ * - If the index is less than the base length, it's in the base config
+ * (as specified by `baseConfig` argument to `FlatConfigArray` constructor).
+ * - If the index is greater than the base length but less than the original
+ * length + base length, it's in the original config. The original config
+ * is passed to the `FlatConfigArray` constructor as the first argument.
+ * - Otherwise, it's in the user-defined config, which is loaded from the
+ * config file and merged with any command-line options.
+ */
+ if (error.index < baseLength) {
+ location = "base";
+ } else if (error.index < originalLength + baseLength) {
+ location = "original";
+ configIndex = error.index - baseLength;
+ } else {
+ configIndex = error.index - originalLength - baseLength;
+ }
+
+ return new TypeError(
+ `${error.message.slice(0, -1)} at ${location} index ${configIndex}.`,
+ { cause: error }
+ );
+}
+
 const originalBaseConfig = Symbol("originalBaseConfig");
+const originalLength = Symbol("originalLength");
+const baseLength = Symbol("baseLength");
 
 //-----------------------------------------------------------------------------
 // Exports
@@ -106,12 +152,24 @@ class FlatConfigArray extends ConfigArray {
  schema: flatConfigSchema
  });
 
+ /**
+ * The original length of the array before any modifications.
+ * @type {number}
+ */
+ this[originalLength] = this.length;
+
  if (baseConfig[Symbol.iterator]) {
  this.unshift(...baseConfig);
  } else {
  this.unshift(baseConfig);
  }
 
+ /**
+ * The length of the array after applying the base config.
+ * @type {number}
+ */
+ this[baseLength] = this.length - this[originalLength];
+
  /**
  * The base config used to build the config array.
  * @type {Array<FlatConfig>}
@@ -129,6 +187,49 @@ class FlatConfigArray extends ConfigArray {
  Object.defineProperty(this, "shouldIgnore", { writable: false });
  }
 
+ /**
+ * Normalizes the array by calling the superclass method and catching/rethrowing
+ * any ConfigError exceptions with additional details.
+ * @param {any} [context] The context to use to normalize the array.
+ * @returns {Promise<FlatConfigArray>} A promise that resolves when the array is normalized.
+ */
+ normalize(context) {
+ return super.normalize(context)
+ .catch(error => {
+ if (error.name === "ConfigError") {
+ throw wrapConfigErrorWithDetails(error, this[originalLength], this[baseLength]);
+ }
+
+ throw error;
+
+ });
+ }
+
+ /**
+ * Normalizes the array by calling the superclass method and catching/rethrowing
+ * any ConfigError exceptions with additional details.
+ * @param {any} [context] The context to use to normalize the array.
+ * @returns {FlatConfigArray} The current instance.
+ * @throws {TypeError} If the config is invalid.
+ */
+ normalizeSync(context) {
+
+ try {
+
+ return super.normalizeSync(context);
+
+ } catch (error) {
+
+ if (error.name === "ConfigError") {
+ throw wrapConfigErrorWithDetails(error, this[originalLength], this[baseLength]);
+ }
+
+ throw error;
+
+ }
+
+ }
+
  /* eslint-disable class-methods-use-this -- Desired as instance method */
  /**
  * Replaces a config with another config to allow us to put strings

diff --git a/package.json b/package.json
@@ -70,7 +70,7 @@
  "@eslint-community/regexpp": "^4.6.1",
  "@eslint/eslintrc": "^3.0.2",
  "@eslint/js": "9.0.0",
- "@humanwhocodes/config-array": "^0.12.3",
+ "@humanwhocodes/config-array": "^0.13.0",
  "@humanwhocodes/module-importer": "^1.0.1",
  "@humanwhocodes/retry": "^0.2.3",
  "@nodelib/fs.walk": "^1.2.8",

diff --git a/tests/lib/config/flat-config-array.js b/tests/lib/config/flat-config-array.js
@@ -191,9 +191,9 @@ async function assertMergedResult(values, result) {
 async function assertInvalidConfig(values, message) {
  const configs = createFlatConfigArray(values);
 
- await configs.normalize();
 
  assert.throws(() => {
+ configs.normalizeSync();
  configs.getConfig("foo.js");
  }, message);
 }
@@ -719,14 +719,162 @@ describe("FlatConfigArray", () => {
  describe("Config array elements", () => {
  it("should error on 'eslint:recommended' string config", async () => {
 
- await assertInvalidConfig(["eslint:recommended"], "All arguments must be objects.");
+ await assertInvalidConfig(["eslint:recommended"], "Config (unnamed): Unexpected non-object config at original index 0.");
  });
 
  it("should error on 'eslint:all' string config", async () => {
 
- await assertInvalidConfig(["eslint:all"], "All arguments must be objects.");
+ await assertInvalidConfig(["eslint:all"], "Config (unnamed): Unexpected non-object config at original index 0.");
+ });
+
+
+ it("should throw an error when undefined original config is normalized", () => {
+
+ const configs = new FlatConfigArray([void 0]);
+
+ assert.throws(() => {
+ configs.normalizeSync();
+ }, "Config (unnamed): Unexpected undefined config at original index 0.");
+
+ });
+
+ it("should throw an error when undefined original config is normalized asynchronously", async () => {
+
+ const configs = new FlatConfigArray([void 0]);
+
+ try {
+ await configs.normalize();
+ assert.fail("Error not thrown");
+ } catch (error) {
+ assert.strictEqual(error.message, "Config (unnamed): Unexpected undefined config at original index 0.");
+ }
+
+ });
+
+ it("should throw an error when null original config is normalized", () => {
+
+ const configs = new FlatConfigArray([null]);
+
+ assert.throws(() => {
+ configs.normalizeSync();
+ }, "Config (unnamed): Unexpected null config at original index 0.");
+
+ });
+
+ it("should throw an error when null original config is normalized asynchronously", async () => {
+
+ const configs = new FlatConfigArray([null]);
+
+ try {
+ await configs.normalize();
+ assert.fail("Error not thrown");
+ } catch (error) {
+ assert.strictEqual(error.message, "Config (unnamed): Unexpected null config at original index 0.");
+ }
+
+ });
+
+ it("should throw an error when undefined base config is normalized", () => {
+
+ const configs = new FlatConfigArray([], { baseConfig: [void 0] });
+
+ assert.throws(() => {
+ configs.normalizeSync();
+ }, "Config (unnamed): Unexpected undefined config at base index 0.");
+
+ });
+
+ it("should throw an error when undefined base config is normalized asynchronously", async () => {
+
+ const configs = new FlatConfigArray([], { baseConfig: [void 0] });
+
+ try {
+ await configs.normalize();
+ assert.fail("Error not thrown");
+ } catch (error) {
+ assert.strictEqual(error.message, "Config (unnamed): Unexpected undefined config at base index 0.");
+ }
+
+ });
+
+ it("should throw an error when null base config is normalized", () => {
+
+ const configs = new FlatConfigArray([], { baseConfig: [null] });
+
+ assert.throws(() => {
+ configs.normalizeSync();
+ }, "Config (unnamed): Unexpected null config at base index 0.");
+
+ });
+
+ it("should throw an error when null base config is normalized asynchronously", async () => {
+
+ const configs = new FlatConfigArray([], { baseConfig: [null] });
+
+ try {
+ await configs.normalize();
+ assert.fail("Error not thrown");
+ } catch (error) {
+ assert.strictEqual(error.message, "Config (unnamed): Unexpected null config at base index 0.");
+ }
+
  });
 
+ it("should throw an error when undefined user-defined config is normalized", () => {
+
+ const configs = new FlatConfigArray([]);
+
+ configs.push(void 0);
+
+ assert.throws(() => {
+ configs.normalizeSync();
+ }, "Config (unnamed): Unexpected undefined config at user-defined index 0.");
+
+ });
+
+ it("should throw an error when undefined user-defined config is normalized asynchronously", async () => {
+
+ const configs = new FlatConfigArray([]);
+
+ configs.push(void 0);
+
+ try {
+ await configs.normalize();
+ assert.fail("Error not thrown");
+ } catch (error) {
+ assert.strictEqual(error.message, "Config (unnamed): Unexpected undefined config at user-defined index 0.");
+ }
+
+ });
+
+ it("should throw an error when null user-defined config is normalized", () => {
+
+ const configs = new FlatConfigArray([]);
+
+ configs.push(null);
+
+ assert.throws(() => {
+ configs.normalizeSync();
+ }, "Config (unnamed): Unexpected null config at user-defined index 0.");
+
+ });
+
+ it("should throw an error when null user-defined config is normalized asynchronously", async () => {
+
+ const configs = new FlatConfigArray([]);
+
+ configs.push(null);
+
+ try {
+ await configs.normalize();
+ assert.fail("Error not thrown");
+ } catch (error) {
+ assert.strictEqual(error.message, "Config (unnamed): Unexpected null config at user-defined index 0.");
+ }
+
+ });
+
+
  });
 
  describe("Config Properties", () => {