From 44fdffabe01484c5b063ede03ebcdba16cb0426b Mon Sep 17 00:00:00 2001
From: Mat Brown <mat.a.brown@gmail.com>
Date: Tue, 26 Mar 2019 06:19:08 -0700
Subject: [PATCH] Gracefully return not found if jest config not found

Since the resolver looks up the Jest config relative to the file
containing the import statement, it will not expect to find a
configuration when recursing through package dependencies. This is fine,
and just means that the resolver should return not found, allowing the
import plugin to fall back to a regular node resolver.

Unfortunately this does make tracking down problems where the
configuration actually is missing more difficult, but I don't see a way
to fix that without completely overhauling the way configuration lookup
is done.
---
 src/__tests__/resolver.test.js | 19 ++++++++++---------
 src/index.js                   |  6 +++---
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/src/__tests__/resolver.test.js b/src/__tests__/resolver.test.js
index f04978e..649fb65 100644
--- a/src/__tests__/resolver.test.js
+++ b/src/__tests__/resolver.test.js
@@ -178,15 +178,16 @@ describe('Jest resolver', () => {
   });
 
   test('Throws when specified config file does not exist', () => {
-    expect(() => {
-      jestResolver.resolve(
-        'resolveme',
-        '/path/to/project/__tests__/iamtest.js',
-        {
-          jestConfigFile: '__tests__/idonotexist.json',
-        }
-      );
-    }).toThrow(/not\sfound/);
+    const result = jestResolver.resolve(
+      'resolveme',
+      '/path/to/project/__tests__/iamtest.js',
+      {
+        jestConfigFile: '__tests__/idonotexist.json',
+      }
+    );
+    expect(result).toEqual({
+      found: false,
+    });
   });
 
   test('Resolves when <rootDir> is in testMatch', () => {
diff --git a/src/index.js b/src/index.js
index e08fdbf..bc10e88 100644
--- a/src/index.js
+++ b/src/index.js
@@ -48,7 +48,7 @@ exports.resolve = function resolver(
   config?: ResolverConfig
 ): ResolverResult {
   const jestConfig = getJestConfig(config, file);
-  if (!isTestFile(jestConfig, file)) {
+  if (jestConfig == null || !isTestFile(jestConfig, file)) {
     return NOTFOUND;
   }
   const pathToResolve = applyModuleNameMapper(jestConfig, source) || source;
@@ -67,7 +67,7 @@ exports.resolve = function resolver(
  * Will use jest configuration from package.json if no jestConfigFile is defined
  * Applies default configuration for any required properties that are undeclared
  */
-function getJestConfig(config?: ResolverConfig = {}, file: Path): JestConfig {
+function getJestConfig(config?: ResolverConfig = {}, file: Path): ?JestConfig {
   let jestConfig;
   const root = findRoot(file);
   if (config.jestConfigFile) {
@@ -75,7 +75,7 @@ function getJestConfig(config?: ResolverConfig = {}, file: Path): JestConfig {
     try {
       jestConfig = require(configFilePath);
     } catch (e) {
-      throw new Error(`jestConfigFile not found in ${configFilePath}`);
+      return undefined;
     }
   } else {
     const packageJson = require(path.resolve(root, 'package.json'));