From cbe7b21090b7744b5ab3116b20db0bd12215c8d3 Mon Sep 17 00:00:00 2001
From: Daniel Imms <daimms@microsoft.com>
Date: Mon, 17 Sep 2018 07:52:37 -0700
Subject: [PATCH] Don't unlink node when updating inBitmap and verify undefined

---
 src/renderer/atlas/DynamicCharAtlas.ts |  6 +++++-
 src/renderer/atlas/LRUMap.ts           | 11 +++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/renderer/atlas/DynamicCharAtlas.ts b/src/renderer/atlas/DynamicCharAtlas.ts
index 31deff55e..04d28c876 100644
--- a/src/renderer/atlas/DynamicCharAtlas.ts
+++ b/src/renderer/atlas/DynamicCharAtlas.ts
@@ -335,7 +335,11 @@ export default class DynamicCharAtlas extends BaseCharAtlas {
       // Mark all new glyphs as in bitmap
       for (let i = 0; i < countAtGeneration; i++) {
         const key = this._glyphsWaitingOnBitmapQueue[i];
-        this._cacheMap.get(key).inBitmap = true;
+        const value = this._cacheMap.peekValue(key);
+        // If the value has already been evicted, do nothing
+        if (value) {
+          value.inBitmap = true;
+        }
         this._glyphsWaitingOnBitmapQueue[i] = 0;
       }
 
diff --git a/src/renderer/atlas/LRUMap.ts b/src/renderer/atlas/LRUMap.ts
index 984dbb724..d7e01ec6c 100644
--- a/src/renderer/atlas/LRUMap.ts
+++ b/src/renderer/atlas/LRUMap.ts
@@ -80,6 +80,17 @@ export default class LRUMap<T> {
     return null;
   }
 
+  /**
+   * Gets a value from a key without marking it as the most recently used item.
+   */
+  public peekValue(key: number): T | null {
+    const node = this._map[key];
+    if (node !== undefined) {
+      return node.value;
+    }
+    return null;
+  }
+
   public peek(): T | null {
     const head = this._head;
     return head === null ? null : head.value;