375684 - assertion when dragging the source is the document root node

Status: RESOLVED FIXED

(Core :: DOM: Copy & Paste and Drag & Drop, defect)

Description

[Neil Deakin]

Attachment: example using document root node, needs chrome privileges

The assertion at http://lxr.mozilla.org/mozilla/source/layout/base/nsPresShell.cpp#5090 shouldn't be used as the range can have the start and end as the document root node, and the ancestor becomes the document. See the attached testcase. 

nsINode* ancestor = nsContentUtils::GetCommonAncestor(range->GetStartParent(),
                      range->GetEndParent());
NS_ASSERTION(!ancestor || ancestor->IsNodeOfType(nsINode::eCONTENT),
             "common ancestor is not content");

roc, I guess in this case, we should just get the document root node and use that?

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Why are we getting the common ancestor of the nodes' parents? Couldn't/shouldn't we just get the common ancestor of the nodes themselves?

Comment 2

[Neil Deakin]

If you're referring to GetStartParent/GetEndParent, they are just perhaps misnamed, they return the nodes themselves.

Comment 3

[Robert O'Callahan (:roc) (email my personal email if necessary)]

OK then, GetCommonAncestor should be returning the root node, right? The common ancestor of two references to the same node is that node.

Comment 4

[Neil Deakin]

This is because nsRange::SelectNode(node) gets the parent of node and then sets the end points based on that.

So I think if the start or end point is the root node, we should just use the root frame instead.

Comment 5

[Robert O'Callahan (:roc) (email my personal email if necessary)]

OK sure.

Comment 6

[Neil Deakin]

Attachment: check if the range parents are the document