fix(coverage): thresholds.autoUpdate to work with arrow function configuration files (#4959)

Author: AriPerkkio

packages/coverage-istanbul/package.json

@@ -51,7 +51,7 @@
     "istanbul-lib-report": "^3.0.1",
     "istanbul-lib-source-maps": "^4.0.1",
     "istanbul-reports": "^3.1.6",
-    "magicast": "^0.3.2",
+    "magicast": "^0.3.3",
     "picocolors": "^1.0.0",
     "test-exclude": "^6.0.0"
   },

packages/coverage-istanbul/src/provider.ts

@@ -4,6 +4,7 @@ import type { AfterSuiteRunMeta, CoverageIstanbulOptions, CoverageProvider, Repo
 import { coverageConfigDefaults, defaultExclude, defaultInclude } from 'vitest/config'
 import { BaseCoverageProvider } from 'vitest/coverage'
 import c from 'picocolors'
+import type { ProxifiedModule } from 'magicast'
 import { parseModule } from 'magicast'
 import createDebug from 'debug'
 import libReport from 'istanbul-lib-report'
@@ -238,9 +239,7 @@ export class IstanbulCoverageProvider extends BaseCoverageProvider implements Co
           perFile: this.options.thresholds.perFile,
           configurationFile: {
             write: () => writeFileSync(configFilePath, configModule.generate().code, 'utf-8'),
-            read: () => configModule.exports.default.$type === 'function-call'
-              ? configModule.exports.default.$args[0]
-              : configModule.exports.default,
+            read: () => resolveConfig(configModule),
           },
         })
       }
@@ -360,3 +359,29 @@ function toSlices<T>(array: T[], size: number): T[][] {
     return chunks
   }, [])
 }
+
+function resolveConfig(configModule: ProxifiedModule<any>) {
+  const mod = configModule.exports.default
+
+  try {
+    // Check for "export default { test: {...} }"
+    if (mod.$type === 'object')
+      return mod
+
+    if (mod.$type === 'function-call') {
+      // "export default defineConfig({ test: {...} })"
+      if (mod.$args[0].$type === 'object')
+        return mod.$args[0]
+
+      // "export default defineConfig(() => ({ test: {...} }))"
+      if (mod.$args[0].$type === 'arrow-function-expression' && mod.$args[0].$body.$type === 'object')
+        return mod.$args[0].$body
+    }
+  }
+  catch (error) {
+    // Reduce magicast's verbose errors to readable ones
+    throw new Error(error instanceof Error ? error.message : String(error))
+  }
+
+  throw new Error('Failed to update coverage thresholds. Configuration file is too complex.')
+}

packages/coverage-v8/package.json

@@ -53,7 +53,7 @@
     "istanbul-lib-source-maps": "^4.0.1",
     "istanbul-reports": "^3.1.6",
     "magic-string": "^0.30.5",
-    "magicast": "^0.3.2",
+    "magicast": "^0.3.3",
     "picocolors": "^1.0.0",
     "std-env": "^3.5.0",
     "test-exclude": "^6.0.0",

packages/coverage-v8/src/provider.ts

@@ -9,6 +9,7 @@ import type { CoverageMap } from 'istanbul-lib-coverage'
 import libCoverage from 'istanbul-lib-coverage'
 import libSourceMaps from 'istanbul-lib-source-maps'
 import MagicString from 'magic-string'
+import type { ProxifiedModule } from 'magicast'
 import { parseModule } from 'magicast'
 import remapping from '@ampproject/remapping'
 import { normalize, resolve } from 'pathe'
@@ -230,9 +231,7 @@ export class V8CoverageProvider extends BaseCoverageProvider implements Coverage
           perFile: this.options.thresholds.perFile,
           configurationFile: {
             write: () => writeFileSync(configFilePath, configModule.generate().code, 'utf-8'),
-            read: () => configModule.exports.default.$type === 'function-call'
-              ? configModule.exports.default.$args[0]
-              : configModule.exports.default,
+            read: () => resolveConfig(configModule),
           },
         })
       }
@@ -432,3 +431,29 @@ function toSlices<T>(array: T[], size: number): T[][] {
     return chunks
   }, [])
 }
+
+function resolveConfig(configModule: ProxifiedModule<any>) {
+  const mod = configModule.exports.default
+
+  try {
+    // Check for "export default { test: {...} }"
+    if (mod.$type === 'object')
+      return mod
+
+    if (mod.$type === 'function-call') {
+      // "export default defineConfig({ test: {...} })"
+      if (mod.$args[0].$type === 'object')
+        return mod.$args[0]
+
+      // "export default defineConfig(() => ({ test: {...} }))"
+      if (mod.$args[0].$type === 'arrow-function-expression' && mod.$args[0].$body.$type === 'object')
+        return mod.$args[0].$body
+    }
+  }
+  catch (error) {
+    // Reduce magicast's verbose errors to readable ones
+    throw new Error(error instanceof Error ? error.message : String(error))
+  }
+
+  throw new Error('Failed to update coverage thresholds. Configuration file is too complex.')
+}