test(core): Resolve @sentry/* to CJS builds in Jest (#6301)

As of JS SDK v10.58.0 the @sentry/* packages expose a `react-native`
export condition pointing at their ESM build. The `react-native` Jest
preset's test environment sets `customExportConditions = ['require',
'react-native']`, so Jest resolves that condition and loads untransformed
ESM (including transitive subpaths like `@sentry/core/browser`), failing
with "Unexpected token 'export'".

Use a custom test environment that drops the `react-native` condition so
these packages resolve to their CJS builds, as they did before 10.58.0.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: antonis

packages/core/jest.config.js

@@ -15,6 +15,13 @@ module.exports = {
     ],
   },
   moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
+  // As of v10.58.0 the JS SDK packages expose a `react-native` export condition that points at
+  // their ESM build. The `react-native` Jest preset's test environment sets
+  // `customExportConditions = ['require', 'react-native']`, so Jest resolves that condition and
+  // loads untransformed ESM (including transitive subpaths like `@sentry/core/browser`), failing
+  // with "Unexpected token 'export'". Use a test environment that drops the `react-native`
+  // condition so these packages resolve to their CJS builds, as they did before the condition.
+  testEnvironment: '<rootDir>/test/RNTestEnvironment.js',
   testPathIgnorePatterns: ['<rootDir>/test/e2e/', '<rootDir>/test/tools/', '<rootDir>/test/react-native/versions'],
   testMatch: ['**/*.test.(ts|tsx)'],
 };

packages/core/test/RNTestEnvironment.js

@@ -0,0 +1,10 @@
+/* eslint-disable @typescript-eslint/no-unsafe-member-access */
+const ReactNativeEnv = require('react-native/jest/react-native-env');
+
+// Extends the `react-native` preset's test environment but drops the `react-native` export
+// condition. Since v10.58.0 the JS SDK packages expose a `react-native` condition pointing at
+// their ESM build; resolving it makes Jest load untransformed ESM. Dropping it makes them resolve
+// to their CJS builds (via the `require` condition), restoring the pre-10.58.0 behaviour.
+module.exports = class extends ReactNativeEnv {
+  customExportConditions = ['require'];
+};