conditional_escape: Try to convert to a string first, then check if SafeData

[Thomas Güttler]

Hi,

if you try to conditional_escape() an object, which unicode
method returns a SafeString, the SafeStrinng gets escaped (one time to much).

I attached a patch with unittest.

All other tests pass.

[Malcolm Tredinnick]

It's fairly dangerous (and I'm not sure it's entirely legal) to have the __unicode__ method return something that isn't simply a Unicode object.

More research required here to determine if this is actually a safe Python practice. If not, the whole issue is moot.

[Thomas Güttler]

This is derived from newforms.utils.ErrorList: There __unicode__()
returns mark_safe(...), too. There, I discoverd the bug. I just
wanted to keep the unittest self-contained.

# newforms.utils.ErrorList:
class ErrorList(list, StrAndUnicode):
    """
    A collection of errors that knows how to display itself in various formats.
    """
    def __unicode__(self):
        return self.as_ul()

    def as_ul(self):
        if not self: return u''
        return mark_safe(u'<ul class="errorlist">%s</ul>'
                % ''.join([u'<li>%s</li>' % force_unicode(e) for e in self]))

[patchhammer]

utils_conditional_escape.diff fails to apply cleanly on to trunk

[Thomas Güttler]

The unittest of the patch still fails, but I (original reporter) close it.