From 44ab4f5864f6a40cd41ff46cff3b7a8dc01658e8 Mon Sep 17 00:00:00 2001
From: Lee Byron <lee@leebyron.com>
Date: Mon, 9 Oct 2017 18:27:19 -0700
Subject: [PATCH] Allow intermediate null value in getIn path.

Fixes #1361
Closes #1362
---
 __tests__/getIn.ts    | 47 ++++++++++++++++++++++++++-----------------
 src/CollectionImpl.js |  4 ++++
 2 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/__tests__/getIn.ts b/__tests__/getIn.ts
index ffb64401ef..86784a51ff 100644
--- a/__tests__/getIn.ts
+++ b/__tests__/getIn.ts
@@ -34,31 +34,34 @@ describe('getIn', () => {
     ).toThrow('Invalid keyPath: expected Ordered Collection or Array: abc');
   });
 
-  it('deep get throws if non-readable path', () => {
+  function withWarnings(fn) {
     const realWarn = console.warn;
     const warnings: Array<any> = [];
     console.warn = w => warnings.push(w);
-
     try {
-      const deep = Map({ key: { regular: "jsobj" }, list: List([ Map({num: 10}) ]) });
-      deep.getIn(["key", "foo", "item"]);
-      expect(warnings.length).toBe(1);
-      expect(warnings[0]).toBe(
-        'Invalid keyPath: Value at ["key"] does not have a .get() method: [object Object]' +
-        '\nThis warning will throw in a future version',
-      );
-
-      warnings.length = 0;
-      deep.getIn(["list", 0, "num", "badKey"]);
-      expect(warnings.length).toBe(1);
-      expect(warnings[0]).toBe(
-        'Invalid keyPath: Value at ["list",0,"num"] does not have a .get() method: 10' +
-        '\nThis warning will throw in a future version',
-      );
+      fn(warnings);
     } finally {
       console.warn = realWarn;
     }
-  });
+  }
+
+  it('deep get throws if non-readable path', withWarnings(warnings => {
+    const deep = Map({ key: { regular: "jsobj" }, list: List([ Map({num: 10}) ]) });
+    deep.getIn(["key", "foo", "item"]);
+    expect(warnings.length).toBe(1);
+    expect(warnings[0]).toBe(
+      'Invalid keyPath: Value at ["key"] does not have a .get() method: [object Object]' +
+      '\nThis warning will throw in a future version',
+    );
+
+    warnings.length = 0;
+    deep.getIn(["list", 0, "num", "badKey"]);
+    expect(warnings.length).toBe(1);
+    expect(warnings[0]).toBe(
+      'Invalid keyPath: Value at ["list",0,"num"] does not have a .get() method: 10' +
+      '\nThis warning will throw in a future version',
+    );
+  }));
 
   it('deep get returns not found if path does not match', () => {
     const m = fromJS({a: {b: {c: 10}}});
@@ -76,4 +79,12 @@ describe('getIn', () => {
     expect(m.getIn(['a', 'b', 'd'], 123)).toEqual(undefined);
   });
 
+  it('deep get returns not found if path encounters null or undefined', withWarnings(warnings => {
+    const m = fromJS({a: {b: {c: null, d: undefined}}});
+    expect(m.getIn(['a', 'b', 'c', 'x'])).toEqual(undefined);
+    expect(m.getIn(['a', 'b', 'd', 'x'])).toEqual(undefined);
+    expect(m.getIn(['a', 'b', 'c', 'x'], 123)).toEqual(123);
+    expect(m.getIn(['a', 'b', 'd', 'x'], 123)).toEqual(123);
+    expect(warnings.length).toBe(0);
+  }));
 });
diff --git a/src/CollectionImpl.js b/src/CollectionImpl.js
index e7f3eefa1d..3a4e102c66 100644
--- a/src/CollectionImpl.js
+++ b/src/CollectionImpl.js
@@ -848,6 +848,10 @@ function getIn(value, notSetValue, searchKeyPath, reportBadKeyPath) {
   const keyPath = coerceKeyPath(searchKeyPath);
   let i = 0;
   while (i !== keyPath.length) {
+    // Intermediate null/undefined value along path
+    if (value == null) {
+      return notSetValue;
+    }
     if (!value || !value.get) {
       if (reportBadKeyPath) {
         warn(