Fix #1753 Make a copy of the cached objects we'll modify.

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/utils/read-installed.js b/lib/utils/read-installed.js
index 6c0ece25b..60cbea15c 100644
--- a/lib/utils/read-installed.js
+++ b/lib/utils/read-installed.js
@@ -125,7 +125,8 @@ function readInstalled_ (folder, parent, name, reqver, depth, maxDepth, cb) {
   })
 
   readJson(path.resolve(folder, "package.json"), function (er, data) {
-    obj = data
+    obj = copy(data)
+
     if (!parent) {
       obj = obj || true
       er = null
@@ -269,6 +270,15 @@ function findUnmet (obj) {
   return obj
 }
 
+function copy (obj) {
+  if (!obj || typeof obj !== 'object') return obj
+  if (Array.isArray(obj)) return obj.map(copy)
+
+  var o = {}
+  for (var i in obj) o[i] = copy(obj[i])
+  return o
+}
+
 if (module === require.main) {
   var util = require("util")
   console.error("testing")