From ed5467689acf519ca160ade6a3cbe3b1f7692535 Mon Sep 17 00:00:00 2001
From: Daniel Imms <daimms@microsoft.com>
Date: Tue, 9 Oct 2018 08:35:49 -0700
Subject: [PATCH] Fix infinite loop

See Microsoft/vscode#60291
---
 src/InputHandler.test.ts | 7 +++++++
 src/InputHandler.ts      | 6 ++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/InputHandler.test.ts b/src/InputHandler.test.ts
index bdd9ccc6d5..e4314330f0 100644
--- a/src/InputHandler.test.ts
+++ b/src/InputHandler.test.ts
@@ -469,4 +469,11 @@ describe('InputHandler', () => {
     }
     expect(s).equals('World          ');
   });
+  describe('print', () => {
+    it('should not cause an infinite loop (regression test)', () => {
+      const term = new Terminal();
+      const inputHandler = new InputHandler(term);
+      inputHandler.print(String.fromCharCode(0x200B), 0, 1);
+    });
+  });
 });
diff --git a/src/InputHandler.ts b/src/InputHandler.ts
index 400e9b9302..ddb20527b5 100644
--- a/src/InputHandler.ts
+++ b/src/InputHandler.ts
@@ -452,8 +452,10 @@ export class InputHandler extends Disposable implements IInputHandler {
       // fullwidth char - also set next cell to placeholder stub and advance cursor
       // for graphemes bigger than fullwidth we can simply loop to zero
       // we already made sure above, that buffer.x + chWidth will not overflow right
-      while (--chWidth) {
-        bufferRow.set(buffer.x++, [curAttr, '', 0, undefined]);
+      if (chWidth > 0) {
+        while (--chWidth) {
+          bufferRow.set(buffer.x++, [curAttr, '', 0, undefined]);
+        }
       }
     }
     this._terminal.updateRange(buffer.y);