Pop stacks when possible.

lodash.js

@@ -2338,14 +2338,17 @@
       if (!isArr) {
         var props = isFull ? getAllKeys(value) : keys(value);
       }
-      // Recursively populate clone (susceptible to call stack limits).
       arrayEach(props || value, function(subValue, key) {
         if (props) {
           key = subValue;
           subValue = value[key];
         }
+        // Recursively populate clone (susceptible to call stack limits).
         assignValue(result, key, baseClone(subValue, isDeep, isFull, customizer, key, value, stack));
       });
+      if (!isFull) {
+        stack['delete'](value);
+      }
       return result;
     }
 
@@ -3249,13 +3252,12 @@
           isCommon = false;
         }
       }
-      stack.set(srcValue, newValue);
-
       if (isCommon) {
         // Recursively merge objects and arrays (susceptible to call stack limits).
+        stack.set(srcValue, newValue);
         mergeFunc(newValue, srcValue, srcIndex, customizer, stack);
+        stack['delete'](srcValue);
       }
-      stack['delete'](srcValue);
       assignMergeValue(object, key, newValue);
     }
 
@@ -5193,10 +5195,12 @@
             return stacked == other;
           }
           bitmask |= UNORDERED_COMPARE_FLAG;
-          stack.set(object, other);
 
           // Recursively compare objects (susceptible to call stack limits).
-          return equalArrays(convert(object), convert(other), equalFunc, customizer, bitmask, stack);
+          stack.set(object, other);
+          var result = equalArrays(convert(object), convert(other), equalFunc, customizer, bitmask, stack);
+          stack['delete'](object);
+          return result;
 
         case symbolTag:
           if (symbolValueOf) {
@@ -5937,7 +5941,10 @@
      */
     function mergeDefaults(objValue, srcValue, key, object, source, stack) {
       if (isObject(objValue) && isObject(srcValue)) {
-        baseMerge(objValue, srcValue, undefined, mergeDefaults, stack.set(srcValue, objValue));
+        // Recursively merge objects and arrays (susceptible to call stack limits).
+        stack.set(srcValue, objValue);
+        baseMerge(objValue, srcValue, undefined, mergeDefaults, stack);
+        stack['delete'](srcValue);
       }
       return objValue;
     }