When the `close` method of the HtmlParser is called, any cached text data is generally flushed and passed to a `data` event; except when in `data_mode`. Specifically, if an unclosed `script` or `style` tag has been encountered, a call to `close` does not flush the data.

A simple test which demonstrates the issue is attached.

I see that in Lib/html/parser.py#L244-L249 there are two nested if statements which both check for `not self.cdata_elem`. Obviously, if we got past the first one, that situation will never exist for the nested one. Somehow this block of code needs a branch for when `self.cdata_elem` is True.

I should note that the input is invalid HTML. However, the existing behavior results in data loss. Within any other unclosed tag (other than `script` or `style`) any data is still flushed and passed to a `data` event. I would expect the same behavior here. Although, the data escaping behavior should perhaps be applied as it is with data within properly closed tags.

Waylan, 3.7 and before only get security fixes.

To me, this might be considered an enhancement rather than bug fix, but I will leave that to Ezio.