Fix hierarchy.revalue.

Post-order traversal alone causes all parent values to be reset to zero
*after* accumulating child values.

An additional pre-order traversal resets all parent values to zero
first, and the post-order traversal can then accumulate child values in
their parents.

This only affects sticky treemaps.

d3.js

@@ -6377,11 +6377,18 @@
       return hierarchy;
     };
     hierarchy.revalue = function(root) {
-      if (value) d3_layout_hierarchyVisitAfter(root, function(node) {
-        var parent;
-        node.value = node.children ? 0 : +value.call(hierarchy, node, node.depth) || 0;
-        if (parent = node.parent) parent.value += node.value;
-      });
+      if (value) {
+        d3_layout_hierarchyVisitBefore(root, function(node) {
+          if (node.children) node.value = 0;
+        });
+        d3_layout_hierarchyVisitAfter(root, function(node) {
+          var parent;
+          if (!node.children) {
+            node.value = +value.call(hierarchy, node, node.depth) || 0;
+          }
+          if (parent = node.parent) parent.value += node.value;
+        });
+      }
       return root;
     };
     return hierarchy;

src/layout/hierarchy.js

@@ -60,11 +60,18 @@ d3.layout.hierarchy = function() {
 
   // Re-evaluates the `value` property for the specified hierarchy.
   hierarchy.revalue = function(root) {
-    if (value) d3_layout_hierarchyVisitAfter(root, function(node) {
-      var parent;
-      node.value = node.children ? 0 : +value.call(hierarchy, node, node.depth) || 0;
-      if (parent = node.parent) parent.value += node.value;
-    });
+    if (value) {
+      d3_layout_hierarchyVisitBefore(root, function(node) {
+        if (node.children) node.value = 0;
+      });
+      d3_layout_hierarchyVisitAfter(root, function(node) {
+        var parent;
+        if (!node.children) {
+          node.value = +value.call(hierarchy, node, node.depth) || 0;
+        }
+        if (parent = node.parent) parent.value += node.value;
+      });
+    }
     return root;
   };
 

test/layout/hierarchy-test.js

@@ -26,6 +26,13 @@ suite.addBatch({
           nodes = h.children(function() { return null; }).nodes({children: [{}]});
       assert.equal(nodes[0].value, 0);
       assert.isUndefined(nodes[0].children);
+    },
+    "revalue": function(hierarchy) {
+      var h = hierarchy().sticky(true),
+          nodes = h.nodes({children: [{children: [{value: 1}, {value: 2}]}, {value: 3}]});
+      assert.equal(nodes[0].value, 6);
+      h(nodes[0]); // calls hierarchy.revalue
+      assert.equal(nodes[0].value, 6);
     }
   }
 });