From 58728e188075be4a9530f9d90716bf5b55b05e7d Mon Sep 17 00:00:00 2001
From: Dennis Shtatnov <densht@gmail.com>
Date: Thu, 4 Jan 2018 09:39:58 -0500
Subject: [PATCH] Fix mangle collision with cache reuse across runs

---
 lib/propmangle.js | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/propmangle.js b/lib/propmangle.js
index c2f27c42..e3f727dd 100644
--- a/lib/propmangle.js
+++ b/lib/propmangle.js
@@ -114,7 +114,8 @@ function mangle_properties(ast, options) {
     if (cache == null) {
         cache = {
             cname: -1,
-            props: new Dictionary()
+            props: new Dictionary(),
+            props_inv: new Dictionary()
         };
     }
 
@@ -214,10 +215,11 @@ function mangle_properties(ast, options) {
             if (!mangled) {
                 do {
                     mangled = base54(++cache.cname);
-                } while (!can_mangle(mangled));
+                } while (!can_mangle(mangled) || cache.props_inv.get(mangled));
             }
 
             cache.props.set(name, mangled);
+            cache.props_inv.set(mangled, name);
         }
         return mangled;
     }