Stream.render bug when strip_whitespace=False

[cboos]

For the context, I noticed that ​TracHacks:WikiGoodiesPlugin's ShowEntities macro was broken, as it displayed things like:

…

…

instead of the expected:

…

…

I traced that to the strip_whitespace parameter of Stream.render:

>>> from genshi.builder import tag
>>> from genshi.core import Markup
>>> table = tag.table(tag.tr(tag.th('…')), tag.td(Markup('…')))
>>> list(table.generate())
[('START', (QName('table'), Attrs()), (None, -1, -1)), ('START', (QName('tr'), Attrs()), (None, -1, -1)), ('START', (QName('th'), Attrs()), (None, -1, -1)), ('TEXT', '&hellip;', (None, -1, -1)), ('END', QName('th'), (None, -1, -1)), ('END', QName('tr'), (None, -1, -1)), ('START', (QName('td'), Attrs()), (None, -1, -1)), ('TEXT', <Markup u'&hellip;'>, (None, -1, -1)), ('END', QName('td'), (None, -1, -1)), ('END', QName('table'), (None, -1, -1))]
>>> table.generate().render('xml')
'<table><tr><th>&amp;hellip;</th></tr><td>&hellip;</td></table>'

All fine so far, but with strip_whitespace=False we get the unexpected:

>>> table.generate().render('xml', encoding=None, strip_whitespace=False)
u'<table><tr><th>&amp;hellip;</th></tr><td>&amp;hellip;</td></table>'

I didn't investigate further yet, what strip_whitespace=False is to prevent the WhitespaceFilter to be added to the XMLSerializer, so the bug happens only when that filter is not present... strange.

Oh wait, this could be a problem with the string cache. I remember when reviewing [1038] that I was afraid that the cache wouldn't make a difference between escaped and unescaped strings, but I was not able to come up with a test case (maybe because I tested with the default strip_whitespace=True). To be continued...

[cboos]

those tests pass on r1037 but test_cache_markup_strip_whitespace fails with r1038