With j2 extension autoescape in Jinja templates is turned off

[zgoda]

https://github.com/pallets/flask/blob/8f422d2b5efe685bf67852b8f06672a32c1f07e6/src/flask/app.py#L808

[ericmjl]

Oh, thanks for the ping in, @zgoda! Would you be kind enough to give me a bit more context here? What would the necessary changes here be? Is it to remove the .j2 extension?

[zgoda]

According to Flask code, template file extension must be one of ".html", ".htm", ".xml", ".xhtml" for autoescape feature to be turned on (in Jinja2 it's off by default). To trigger autoescaping for other file name extensions one has to subclass Flask and override Flask.select_jinja_autoescape, eg.:

    def select_jinja_autoescape(self, filename):
        orig_select = super().select_jinja_autoescape(filename)
        return orig_select or filename.endswith(('.jinja', '.jinja2', '.j2'))