Throw an error for the old config (#105)

.changeset/olive-planets-retire.md

@@ -0,0 +1,5 @@
+---
+'steiger': minor
+---
+
+Add error messages for invalid config shapes

packages/steiger/src/models/config/index.ts

@@ -3,7 +3,7 @@ import { Config, GlobalIgnore, Plugin } from '@steiger/types'
 
 import createRuleInstructions from './create-rule-instructions'
 import { RuleInstructions } from './types'
-import buildValidationScheme from './build-validation-scheme'
+import { validateConfig } from './validate-config'
 import { isGlobalIgnore, isPlugin } from './raw-config'
 import { transformGlobs } from './transform-globs'
 
@@ -32,9 +32,7 @@ export const $enabledRules = combine($ruleInstructions, $plugins, (ruleInstructi
 })
 
 export function processConfiguration(rawConfig: Config, configLocationFolder: string | null) {
-  const validationScheme = buildValidationScheme(rawConfig)
-  const validatedConfig = validationScheme.parse(rawConfig)
-
+  const validatedConfig = validateConfig(rawConfig)
   const plugins = rawConfig.filter(isPlugin)
   const configTransformedGlobs = transformGlobs(validatedConfig, configLocationFolder)
   const ruleInstructions = createRuleInstructions(configTransformedGlobs)

packages/steiger/src/models/config/build-validation-scheme.spec.ts → packages/steiger/src/models/config/validate-config.spec.ts

@@ -1,7 +1,7 @@
 import { describe, expect, it } from 'vitest'
 import { Config, Plugin } from '@steiger/types'
 
-import buildValidationScheme from './build-validation-scheme'
+import { buildValidationScheme, validateConfig } from './validate-config'
 import { isPlugin } from './raw-config'
 
 // The function maps a plugin object to a new object with the same properties as the original object,
@@ -313,3 +313,21 @@ describe('buildValidationScheme', () => {
     expect(() => scheme.parse(config)).toThrow()
   })
 })
+
+describe('validateConfig', () => {
+  it('should throw an error when an old-style config is provided', () => {
+    // @ts-expect-error testing invalid input
+    expect(() => validateConfig({})).toThrow()
+  })
+
+  it('should throw an error when a config of wrong shape is provided ', () => {
+    // @ts-expect-error testing invalid input
+    expect(() => validateConfig('')).toThrow()
+
+    // @ts-expect-error testing invalid input
+    expect(() => validateConfig(234234234)).toThrow()
+
+    // @ts-expect-error testing invalid input
+    expect(() => validateConfig(true)).toThrow()
+  })
+})

packages/steiger/src/models/config/build-validation-scheme.ts → packages/steiger/src/models/config/validate-config.ts

@@ -1,8 +1,16 @@
 import z from 'zod'
 
+import { BaseRuleOptions, Config, Plugin, Severity } from '@steiger/types'
+
 import { getOptions, isConfigObject, isPlugin } from './raw-config'
 import { isEqual } from '../../shared/objects'
-import { BaseRuleOptions, Config, Plugin, Severity } from '@steiger/types'
+
+const OLD_CONFIG_ERROR_MESSAGE =
+  'Old configuration format detected. We are evolving!\nPlease follow this short guide to migrate to the new one:\nhttps://github.com/feature-sliced/steiger/blob/master/MIGRATION_GUIDE.md'
+const WRONG_CONFIG_SHAPE_ERROR_MESSAGE =
+  'The config should be an Array, but the provided config is not.\nHere is a link to the documentation that might help to fix it:\nhttps://github.com/feature-sliced/steiger?tab=readme-ov-file#configuration'
+const NO_RULES_ERROR_MESSAGE = 'At least one rule must be provided by plugins!'
+const NO_CONFIG_OBJECTS_ERROR_MESSAGE = 'At least one config object must be provided!'
 
 function getAllRuleNames(plugins: Array<Plugin>) {
   const allRules = plugins.flatMap((plugin) => plugin.ruleDefinitions)
@@ -15,7 +23,7 @@ function validateConfigObjectsNumber(value: Config, ctx: z.RefinementCtx) {
   if (configObjects.length === 0) {
     ctx.addIssue({
       code: z.ZodIssueCode.custom,
-      message: 'At least one config object must be provided!',
+      message: NO_CONFIG_OBJECTS_ERROR_MESSAGE,
     })
   }
 }
@@ -69,13 +77,13 @@ function validateRuleOptions(value: Config, ctx: z.RefinementCtx) {
 /**
  * Dynamically build a validation scheme based on the rules provided by plugins.
  * */
-export default function buildValidationScheme(rawConfig: Config) {
+export function buildValidationScheme(rawConfig: Config) {
   const allRuleNames = getAllRuleNames(rawConfig.filter(isPlugin))
 
   // Make sure there's at least one rule registered by plugins
   // Need to check this before creating the scheme, because zod.enum requires at least one element
   if (allRuleNames.length === 0) {
-    throw new Error('At least one rule must be provided by plugins!')
+    throw new Error(NO_RULES_ERROR_MESSAGE)
   }
 
   // Marked as "any" because return type is not useful for this validation
@@ -124,3 +132,21 @@ export default function buildValidationScheme(rawConfig: Config) {
     .superRefine(validateRuleOptions)
     .superRefine(validateRuleUniqueness)
 }
+
+export function validateConfig(rawConfig: Config) {
+  const isOldConfig = typeof rawConfig === 'object' && !Array.isArray(rawConfig)
+  const isWrongShape = !Array.isArray(rawConfig)
+
+  // Need to check the shape of the config separately before validating it,
+  // because building a validation scheme requires the config to be an array
+  if (isOldConfig) {
+    throw new Error(OLD_CONFIG_ERROR_MESSAGE)
+  }
+
+  if (isWrongShape) {
+    throw new Error(WRONG_CONFIG_SHAPE_ERROR_MESSAGE)
+  }
+
+  const validationScheme = buildValidationScheme(rawConfig)
+  return validationScheme.parse(rawConfig)
+}