From: transfire@...
Date: 2006-07-09T00:37:53+09:00
Subject: Re: libhxml Node#remove! kills each loop and extension to #<<


Matthew Smillie wrote:
> I'm not aware (and couldn't find) any libhxml - if you meant ruby-
> libxml (which seems likely given the problem), here's what I figured
> out.

:) Yes libxml bindings is indeed what I was refering (h was a typo)

> At first, I thought it could be a bug caused by modification to the
> structure you're iterating over, similar to this:
>
> root = ['a','b','c']
> root.each { |node| root.delete(node) if node == "b" }
>
> which will skip over 'c' due to the deletion.
>
> But while I was trying to confirm this in libxml, I found behaviour
> that makes me think there's some more fundamental bug.  Redefining a
> variable seemed to have some very odd effects, which I managed to
> reduce to this case:

[snip]

> => <root>
>    <a/>
>    <b/>      # where did *this* come from?
> </root>
>
> (That's the existing definition of #<<, not your extension)
>
> Exiting from the irb session results in a segmentation fault, and
> running the same code outside of irb yields the same apparent results
> (inclusion of 'b' where it shouldn't be), and resulted in a bus
> error.  I have the hunch that the C extension isn't managing memory
> properly, which is confirmed by one of the errors submitted on the
> project page.  Maybe this is just my setup (1.8.4 on OSX), but it
> seems to me that the library has enough problems that it's not quite
> ready for use.

Thanks matthew. Very enlightening. I decdided to write a xml wrapper
and create an common interface for either REXML and libxml. That way I
can use REXML for now and easy switch over when libxml binding are
fully operational.

T.