feat: config validation (#2412)

* feat: basic user config validation

* fix: simplify config resolution and fix issue #327

* fix: remove no longer needed function

* fix: disable some unwanted validations

* fix: improve config validation

* fix: remove redundant validation

* fix: use reduceRight instead of reverse

* fix: rollback some code

* fix: drop invalid type casts

* fix: rollback unnecessary changes

* fix: rollback config validation

* fix: add missing type-guards and restore order

* fix: one more order change

* fix: add one more missing type guard

* fix: remove unused types reference

* fix: add additional unit tests

* fix: add additional regression tests
- remove also unnecessary type check

* fix: remove more unnecessary code changes

* fix: correct order of merging plugins

* fix: add missing type check

* fix: remove invalid type check

* fix: remove redundant code

* feat: implement config validation

* fix: allow to use function as a rule

@commitlint/cli/src/cli.ts

@@ -7,14 +7,15 @@ import resolveGlobal from 'resolve-global';
 import yargs, {Arguments} from 'yargs';
 import util from 'util';
 
-import {CliFlags, Seed} from './types';
+import {CliFlags} from './types';
 import {
 	LintOptions,
 	LintOutcome,
 	ParserOptions,
 	ParserPreset,
 	QualifiedConfig,
 	Formatter,
+	UserConfig,
 } from '@commitlint/types';
 import {CliError} from './cli-error';
 
@@ -364,7 +365,7 @@ function getEditValue(flags: CliFlags) {
 	return edit;
 }
 
-function getSeed(flags: CliFlags): Seed {
+function getSeed(flags: CliFlags): UserConfig {
 	const n = (flags.extends || []).filter(
 		(i): i is string => typeof i === 'string'
 	);

@commitlint/cli/src/types.ts

@@ -18,8 +18,3 @@ export interface CliFlags {
 	_: (string | number)[];
 	$0: string;
 }
-
-export interface Seed {
-	extends?: string[];
-	parserPreset?: string;
-}

@commitlint/config-validator/package.json

@@ -0,0 +1,45 @@
+{
+  "name": "@commitlint/config-validator",
+  "version": "15.0.0",
+  "description": "config validator for commitlint.config.js",
+  "main": "lib/validate.js",
+  "types": "lib/validate.d.ts",
+  "files": [
+    "lib/"
+  ],
+  "scripts": {
+    "deps": "dep-check",
+    "pkg": "pkg-check --skip-import"
+  },
+  "engines": {
+    "node": ">=v12"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/conventional-changelog/commitlint.git",
+    "directory": "@commitlint/config-validator"
+  },
+  "bugs": {
+    "url": "https://github.com/conventional-changelog/commitlint/issues"
+  },
+  "homepage": "https://commitlint.js.org/",
+  "keywords": [
+    "conventional-changelog",
+    "commitlint",
+    "library",
+    "core"
+  ],
+  "author": {
+    "name": "Mario Nebl",
+    "email": "hello@herebecode.com"
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "@commitlint/utils": "^15.0.0"
+  },
+  "dependencies": {
+    "@commitlint/types": "^15.0.0",
+    "ajv": "^6.12.6"
+  },
+  "gitHead": "d829bf6260304ca8d6811f329fcdd1b6c50e9749"
+}

@commitlint/config-validator/src/__snapshots__/validate.test.ts.snap

@@ -0,0 +1,134 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`validation should fail for defaultIgnoresNotBoolean 1`] = `
+"Commitlint configuration in defaultIgnoresNotBoolean.js is invalid:
+	- Property \\"defaultIgnores\\" has the wrong type - should be boolean.
+"
+`;
+
+exports[`validation should fail for extendsAsObject 1`] = `
+"Commitlint configuration in extendsAsObject.js is invalid:
+	- Property \\"extends\\" has the wrong type - should be array.
+	- Property \\"extends\\" has the wrong type - should be string.
+	- \\"extends\\" should match exactly one schema in oneOf. Value: {\\"test\\":1}.
+"
+`;
+
+exports[`validation should fail for extendsWithFunction 1`] = `
+"Commitlint configuration in extendsWithFunction.js is invalid:
+	- Property \\"extends[0]\\" has the wrong type - should be string.
+	- Property \\"extends\\" has the wrong type - should be string.
+	- \\"extends\\" should match exactly one schema in oneOf. Value: [null].
+"
+`;
+
+exports[`validation should fail for formatterAsObject 1`] = `
+"Commitlint configuration in formatterAsObject.js is invalid:
+	- Property \\"formatter\\" has the wrong type - should be string.
+"
+`;
+
+exports[`validation should fail for helpUrlAsArray 1`] = `
+"Commitlint configuration in helpUrlAsArray.js is invalid:
+	- Property \\"helpUrl\\" has the wrong type - should be string.
+"
+`;
+
+exports[`validation should fail for helpUrlNotString 1`] = `
+"Commitlint configuration in helpUrlNotString.js is invalid:
+	- Property \\"helpUrl\\" has the wrong type - should be string.
+"
+`;
+
+exports[`validation should fail for ignoresFunction 1`] = `
+"Commitlint configuration in ignoresFunction.js is invalid:
+	- Property \\"ignores\\" has the wrong type - should be array.
+"
+`;
+
+exports[`validation should fail for ignoresNotFunction 1`] = `
+"Commitlint configuration in ignoresNotFunction.js is invalid:
+	- \\"ignores[0]\\" should be a function. Value: 1.
+"
+`;
+
+exports[`validation should fail for parserPreset 1`] = `
+"Commitlint configuration in parserPreset.js is invalid:
+	- Property \\"parserPreset\\" has the wrong type - should be string.
+	- Property \\"parserPreset\\" has the wrong type - should be object.
+	- \\"parserPreset\\" should match exactly one schema in oneOf. Value: [].
+"
+`;
+
+exports[`validation should fail for pluginsNotArray 1`] = `
+"Commitlint configuration in pluginsNotArray.js is invalid:
+	- Property \\"plugins\\" has the wrong type - should be array.
+"
+`;
+
+exports[`validation should fail for rules1 1`] = `
+"Commitlint configuration in rules1.js is invalid:
+	- \\"rules['a'][0]\\" should be equal to one of the allowed values. Value: 3.
+	- \\"rules['a']\\" should be a function. Value: [3].
+	- \\"rules['a']\\" should match exactly one schema in oneOf. Value: [3].
+"
+`;
+
+exports[`validation should fail for rules2 1`] = `
+"Commitlint configuration in rules2.js is invalid:
+	- \\"rules['b']\\" should NOT have more than 3 items. Value: [1,\\"test\\",2,2].
+	- \\"rules['b']\\" should be a function. Value: [1,\\"test\\",2,2].
+	- \\"rules['b']\\" should match exactly one schema in oneOf. Value: [1,\\"test\\",2,2].
+"
+`;
+
+exports[`validation should fail for rules3 1`] = `
+"Commitlint configuration in rules3.js is invalid:
+	- \\"rules['c']\\" should NOT have fewer than 1 items. Value: [].
+	- \\"rules['c']\\" should be a function. Value: [].
+	- \\"rules['c']\\" should match exactly one schema in oneOf. Value: [].
+"
+`;
+
+exports[`validation should fail for rules4 1`] = `
+"Commitlint configuration in rules4.js is invalid:
+	- Property \\"rules['d'][0]\\" has the wrong type - should be number.
+	- \\"rules['d'][0]\\" should be equal to one of the allowed values. Value: [].
+	- \\"rules['d']\\" should be a function. Value: [[],[],[]].
+	- \\"rules['d']\\" should match exactly one schema in oneOf. Value: [[],[],[]].
+"
+`;
+
+exports[`validation should fail for rules5 1`] = `
+"Commitlint configuration in rules5.js is invalid:
+	- Property \\"rules['e']\\" has the wrong type - should be array.
+	- \\"rules['e']\\" should be a function. Value: {}.
+	- \\"rules['e']\\" should match exactly one schema in oneOf. Value: {}.
+"
+`;
+
+exports[`validation should fail for rulesAsArray 1`] = `
+"Commitlint configuration in rulesAsArray.js is invalid:
+	- Property \\"rules\\" has the wrong type - should be object.
+"
+`;
+
+exports[`validation should fail for whenConfigIsNotObject 1`] = `
+"Commitlint configuration in whenConfigIsNotObject.js is invalid:
+	- Config has the wrong type - should be object.
+"
+`;
+
+exports[`validation should fail for whenConfigIsNotObject2 1`] = `
+"Commitlint configuration in whenConfigIsNotObject2.js is invalid:
+	- Config has the wrong type - should be object.
+"
+`;
+
+exports[`validation should fail for withPluginsAsObject 1`] = `
+"Commitlint configuration in withPluginsAsObject.js is invalid:
+	- Property \\"plugins[0]\\" has the wrong type - should be string.
+	- \\"plugins[0]\\" should have required property '.rules'. Value: {}.
+	- \\"plugins[0]\\" should match some schema in anyOf. Value: {}.
+"
+`;

@commitlint/config-validator/src/commitlint.schema.json

@@ -0,0 +1,100 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema",
+  "default": {},
+  "type": "object",
+  "definitions": {
+    "rule": {
+      "oneOf": [
+        {
+          "description": "A rule",
+          "type": "array",
+          "items": [
+            {
+              "description": "Level: 0 disables the rule. For 1 it will be considered a warning, for 2 an error",
+              "type": "number",
+              "enum": [0, 1, 2]
+            },
+            {
+              "description": "Applicable: always|never: never inverts the rule",
+              "type": "string",
+              "enum": ["always", "never"]
+            },
+            {
+              "description": "Value: the value for this rule"
+            }
+          ],
+          "minItems": 1,
+          "maxItems": 3,
+          "additionalItems": false
+        },
+        {
+          "description": "A rule",
+          "typeof": "function"
+        }
+      ]
+    }
+  },
+  "properties": {
+    "extends": {
+      "description": "Resolveable ids to commitlint configurations to extend",
+      "oneOf": [
+        {
+          "type": "array",
+          "items": {"type": "string"}
+        },
+        {"type": "string"}
+      ]
+    },
+    "parserPreset": {
+      "description": "Resolveable id to conventional-changelog parser preset to import and use",
+      "oneOf": [
+        {"type": "string"},
+        {
+          "type": "object",
+          "properties": {
+            "name": {"type": "string"},
+            "path": {"type": "string"},
+            "parserOpts": {}
+          },
+          "additionalProperties": true
+        }
+      ]
+    },
+    "helpUrl": {
+      "description": "Custom URL to show upon failure",
+      "type": "string"
+    },
+    "formatter": {
+      "description": "Resolveable id to package, from node_modules, which formats the output",
+      "type": "string"
+    },
+    "rules": {
+      "description": "Rules to check against",
+      "type": "object",
+      "propertyNames": {"type": "string"},
+      "additionalProperties": {"$ref": "#/definitions/rule"}
+    },
+    "plugins": {
+      "description": "Resolveable ids of commitlint plugins from node_modules",
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {"type": "string"},
+          {
+            "required": ["rules"],
+            "rules": {}
+          }
+        ]
+      }
+    },
+    "ignores": {
+      "type": "array",
+      "items": {"typeof": "function"},
+      "description": "Additional commits to ignore, defined by ignore matchers"
+    },
+    "defaultIgnores": {
+      "description": "Whether commitlint uses the default ignore rules",
+      "type": "boolean"
+    }
+  }
+}

@commitlint/config-validator/src/formatErrors.ts

@@ -0,0 +1,45 @@
+import {ErrorObject} from 'ajv';
+
+/**
+ * Formats an array of schema validation errors.
+ * @param errors An array of error messages to format.
+ * @returns Formatted error message
+ * Based on https://github.com/eslint/eslint/blob/master/lib/shared/config-validator.js#L237-L261
+ */
+export function formatErrors(errors: ErrorObject[]): string {
+	return errors
+		.map((error) => {
+			if (
+				error.keyword === 'additionalProperties' &&
+				'additionalProperty' in error.params
+			) {
+				const formattedPropertyPath = error.dataPath.length
+					? `${error.dataPath.slice(1)}.${error.params.additionalProperty}`
+					: error.params.additionalProperty;
+
+				return `Unexpected top-level property "${formattedPropertyPath}"`;
+			}
+			if (error.keyword === 'type') {
+				const formattedField = error.dataPath.slice(1);
+				if (!formattedField) {
+					return `Config has the wrong type - ${error.message}`;
+				}
+				return `Property "${formattedField}" has the wrong type - ${error.message}`;
+			}
+			const field =
+				(error.dataPath[0] === '.'
+					? error.dataPath.slice(1)
+					: error.dataPath) || 'Config';
+			if (error.keyword === 'typeof') {
+				return `"${field}" should be a ${error.schema}. Value: ${JSON.stringify(
+					error.data
+				)}`;
+			}
+
+			return `"${field}" ${error.message}. Value: ${JSON.stringify(
+				error.data
+			)}`;
+		})
+		.map((message) => `\t- ${message}.\n`)
+		.join('');
+}