From bb93e339fa6adb300ee1c843e833209e389d05e1 Mon Sep 17 00:00:00 2001
From: James Ide <ide@expo.io>
Date: Tue, 16 Jan 2018 17:08:30 -0800
Subject: [PATCH] Use `error.message` to set the `description` property of a
 nested error payload

Summary:
Depends on #124.

 ---

**Summary**
Metro reports errors using a JSON payload that has an `errors` array. Each item in this array has a `description` field. For transform errors, this field was set using the value in `error.description` -- however, JS Error objects only have a `message` field. (Grepping the Metro code, no errors (except in one test) ever get a `description` field.) This commit uses `error.message` instead of `error.description` when creating JSON payloads.

```
$ git grep description -- 'packages/**/*.js'
packages/metro/src/JSTransformer/__tests__/Transformer-test.js:        babelError.description = message;
packages/metro/src/lib/formatBundlingError.js:    description: string,
packages/metro/src/lib/formatBundlingError.js:): {type: string, message: string, errors: Array<{description: string}>} {
packages/metro/src/lib/formatBundlingError.js:      errors: [{description: message}],
packages/metro/src/lib/formatBundlingError.js:        description: error.message,
packages/metro/src/node-haste/__tests__/Module-test.js:  description: "A require('foo') story",
```

**Test Plan**
Added a unit test to check that the description field is set for transform errors (with the delta bundler).

Also in a test RN app, inspected the error payload that is received by RN when there's a syntax error with HMR turned on and verified that `data.body.errors[0].description` was set.
Closes https://github.com/facebook/metro/pull/125

Differential Revision: D6730671

Pulled By: rafeca

fbshipit-source-id: 58311462db9223d65580d77748203d8ea0ea1ac7
---
 packages/metro/src/HmrServer/__tests__/HmrServer-test.js       | 1 +
 packages/metro/src/JSTransformer/__tests__/Transformer-test.js | 1 -
 packages/metro/src/Server/__tests__/Server-test.js             | 1 +
 packages/metro/src/lib/formatBundlingError.js                  | 3 +--
 4 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/metro/src/HmrServer/__tests__/HmrServer-test.js b/packages/metro/src/HmrServer/__tests__/HmrServer-test.js
index cf6fa15e..ac926db4 100644
--- a/packages/metro/src/HmrServer/__tests__/HmrServer-test.js
+++ b/packages/metro/src/HmrServer/__tests__/HmrServer-test.js
@@ -158,6 +158,7 @@ describe('HmrServer', () => {
         message: 'test syntax error',
         errors: [
           {
+            description: 'test syntax error',
             filename: 'EntryPoint.js',
             lineNumber: 123,
           },
diff --git a/packages/metro/src/JSTransformer/__tests__/Transformer-test.js b/packages/metro/src/JSTransformer/__tests__/Transformer-test.js
index 654a3364..181581da 100644
--- a/packages/metro/src/JSTransformer/__tests__/Transformer-test.js
+++ b/packages/metro/src/JSTransformer/__tests__/Transformer-test.js
@@ -87,7 +87,6 @@ describe('Transformer', function() {
         const babelError = new SyntaxError(message);
 
         babelError.type = 'SyntaxError';
-        babelError.description = message;
         babelError.loc = {line: 2, column: 15};
         babelError.codeFrame = snippet;
 
diff --git a/packages/metro/src/Server/__tests__/Server-test.js b/packages/metro/src/Server/__tests__/Server-test.js
index 3510b5d5..25f786a5 100644
--- a/packages/metro/src/Server/__tests__/Server-test.js
+++ b/packages/metro/src/Server/__tests__/Server-test.js
@@ -320,6 +320,7 @@ describe('processRequest', () => {
             message: 'test syntax error',
           });
           expect(body.errors).toContainEqual({
+            description: 'test syntax error',
             filename: 'testFile.js',
             lineNumber: 123,
           });
diff --git a/packages/metro/src/lib/formatBundlingError.js b/packages/metro/src/lib/formatBundlingError.js
index 3bbdf9af..6a7155b5 100644
--- a/packages/metro/src/lib/formatBundlingError.js
+++ b/packages/metro/src/lib/formatBundlingError.js
@@ -24,7 +24,6 @@ const {
 export type CustomError = Error & {|
   status?: number,
   type?: string,
-  description?: string,
   filename?: string,
   lineNumber?: number,
   errors?: Array<{
@@ -63,7 +62,7 @@ function formatBundlingError(
   ) {
     error.errors = [
       {
-        description: error.description,
+        description: error.message,
         filename: error.filename,
         lineNumber: error.lineNumber,
       },