From 56133115cd70061d170c6d9f7bb7ec9166da76ab Mon Sep 17 00:00:00 2001
From: Moti Zilberman <motiz88@gmail.com>
Date: Mon, 1 Apr 2019 17:36:46 +0100
Subject: [PATCH] fix: sort modules in debugger delta patcher to match source
 map order (#279)

Summary:
---------

Context: https://github.com/facebook/metro/issues/380, https://github.com/facebook/react-native/issues/23955

Fixes a discrepancy between the order of modules in the source map and in the actual bundle, caused by a change in Metro (see details in https://github.com/facebook/metro/issues/380#issuecomment-478633831). Consequently fixes React Native remote JS debugging.

Test Plan:
----------

1. Made the same change in my checkout of the repro code from https://github.com/facebook/metro/issues/380 and verified debugging works.
2. Added unit tests.
---
 .../server/debugger-ui/DeltaPatcher.js        |  5 +-
 .../__tests__/DeltaPatcher-test.js            | 51 +++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/packages/cli/src/commands/server/debugger-ui/DeltaPatcher.js b/packages/cli/src/commands/server/debugger-ui/DeltaPatcher.js
index ed950295f6..25c9f36900 100644
--- a/packages/cli/src/commands/server/debugger-ui/DeltaPatcher.js
+++ b/packages/cli/src/commands/server/debugger-ui/DeltaPatcher.js
@@ -119,7 +119,10 @@
     getAllModules() {
       return [].concat(
         [this._lastBundle.pre],
-        Array.from(this._lastBundle.modules.values()),
+        // Sort modules so they match the source map emitted by Metro >= 0.51.0
+        Array.from(this._lastBundle.modules.entries())
+          .sort(([id1], [id2]) => id1 - id2)
+          .map(([id, contents]) => contents),
         [this._lastBundle.post],
       );
     }
diff --git a/packages/cli/src/commands/server/debugger-ui/__tests__/DeltaPatcher-test.js b/packages/cli/src/commands/server/debugger-ui/__tests__/DeltaPatcher-test.js
index 2bd9db3396..caae8e599c 100644
--- a/packages/cli/src/commands/server/debugger-ui/__tests__/DeltaPatcher-test.js
+++ b/packages/cli/src/commands/server/debugger-ui/__tests__/DeltaPatcher-test.js
@@ -108,4 +108,55 @@ describe('DeltaPatcher', () => {
     expect(dp.getLastNumModifiedFiles()).toBe(2);
     expect(dp.getAllModules()).toEqual(['pre2', '__d(4);', '__d(5);', 'post2']);
   });
+  
+  it('should sort modules after receiving an unsorted base bundle', () => {
+    const dp = new window.DeltaPatcher();
+    global.Date = jest.fn();
+    dp.applyDelta({
+      base: true,
+      revisionId: 'rev0',
+      pre: 'pre0',
+      post: 'post0',
+      modules: [[2, '__d(2);'], [3, '__d(3);'], [0, '__d(0);'], [1, '__d(1);']],
+    });
+    expect(dp.getLastRevisionId()).toBe('rev0');
+    expect(dp.getLastModifiedDate()).toBe(global.Date.mock.instances[0]);
+    expect(dp.getLastNumModifiedFiles()).toBe(4);
+    expect(dp.getAllModules()).toEqual([
+      'pre0',
+      '__d(0);',
+      '__d(1);',
+      '__d(2);',
+      '__d(3);',
+      'post0',
+    ]);
+  });
+
+  it('should sort modules after receiving an unsorted delta bundle', () => {
+    const dp = new window.DeltaPatcher();
+    dp.applyDelta({
+      base: true,
+      revisionId: 'rev0',
+      pre: 'pre0',
+      post: 'post0',
+      modules: [[2, '__d(2);'], [1, '__d(1);'], [0, '__d(0);']],
+    });
+    global.Date = jest.fn();
+    dp.applyDelta({
+      base: false,
+      revisionId: 'rev1',
+      modules: [[3, '__d(3);'], [1, '__d(1.1);']],
+      deleted: [0],
+    });
+    expect(dp.getLastRevisionId()).toBe('rev1');
+    expect(dp.getLastModifiedDate()).toBe(global.Date.mock.instances[0]);
+    expect(dp.getLastNumModifiedFiles()).toBe(3);
+    expect(dp.getAllModules()).toEqual([
+      'pre0',
+      '__d(1.1);',
+      '__d(2);',
+      '__d(3);',
+      'post0',
+    ]);
+  });
 });