I get a crash, not warnings:

(gdb) bt full

+ Trace 64376

(gdb) p *stream
$1 = {parent_object = {g_type_instance = {g_class = 0x0},
    ref_count = 2863311530, qdata = 0xaaaaaaaa}, write_func = 0xaaaaaaaa,
  close_func = 0xaaaaaaaa, cancel_func = 0xaaaaaaaa, user_data = 0xaaaaaaaa,
  cancel_data = 0xaaaaaaaa, written = -1431655766,
  mime_type = 0xaaaaaaaa <Address 0xaaaaaaaa out of bounds>}

So the document->current_stream object is dead but gtkhtml2 doesn't know it. 
This is not a wrapper bug...

Python code that triggers the crash:
[...]
    document.clear()
    headers = f.info()
    mime = headers.getheader('Content-type')
    if mime:
        document.open_stream(mime)
    else:
        document.open_stream('text/plain')
    document.write_stream(f.read()) # <--- crashes here
    document.close_stream()

Just for the record,

I just tested it in a Debian machine, with the previous bindings and it works ok, even with the new libgtkhtml2.

ii  libgtkhtml2-0       2.6.3-1
ii  python-gtk2         2.6.3-2
ii  python2.3-gtk2      2.6.3-2

This sounds like a bindings bug, not a gtkhtml2 bug to me. Can someone confirm this and move to the proper product/component for the python bindings if so?

I originally filled the bug into python binding, bug the findings of Gustavo, hi moved to gtkhtml2.

I forgot to remark the Gustavo's comment:

"...
(gdb) p *stream
$1 = {parent_object = {g_type_instance = {g_class = 0x0},
    ref_count = 2863311530, qdata = 0xaaaaaaaa}, write_func = 0xaaaaaaaa,
  close_func = 0xaaaaaaaa, cancel_func = 0xaaaaaaaa, user_data = 0xaaaaaaaa,
  cancel_data = 0xaaaaaaaa, written = -1431655766,
  mime_type = 0xaaaaaaaa <Address 0xaaaaaaaa out of bounds>}

So the document->current_stream object is dead but gtkhtml2 doesn't know it. 
This is not a wrapper bug...
"

Can you attach a script or equivalent C code that reproduces this problem then? What is simple-browser.py? It's not obvious to me how to reproduce the problem, looking at the backtrace.

Created attachment 71196 [details]
Python script test-case

This is the python script bundled as example of gnome-python-extras.  It also locate at http://cvs.gnome.org/viewcvs/gnome-python-extras/examples/gtkhtml2/

The script used to work and the last time it was modified was 4 years ago.

Steps to reproduce it:

1. Run it in a terminal:
   $ python ./simple-browser.py
2. Click over the link 'click me'.

OK. The problem is that the bindings are reporting that the html_document_open_stream call has no return value, when the C API returns a boolean. I don't see how this ever worked, unless www.gnome.org was returning only "Content-type: text/html" in the headers before. The "; charset=utf-8" is causing html_document_open_stream () to fail, when you pass in the content-type header value directly without parsing it, and then you try to write/close on a stream that doesn't exist. The only thing that changed in the last 5 years in the html_document_open_stream method, is that padraig added an html_document_clear call to the method, so that it automatically clears it.

This is definitely an issue with the bindings and simple-browser.py code, as it isn't doing any proper error checking, and ignores a boolean return value. And for what it's worth, the API only handles "text/html" as a valid mime type, so even in the fallback case in simple-browser.py, it would still fail, as it returns FALSE if the type is not "text/html".

Thanks, indeed it was a bug in the example program.
I also made the bindings raise an exception when html_document_open_stream returns FALSE.

Fixed in CVS. The fix will go into the next patch release. Thank you for your bug report.

*** Bug 360891 has been marked as a duplicate of this bug. ***