For optimal performance req.chrome should be evaluated only if necessary.

[Olemis Lang]

When the plugin is installed and active it's post_process_request() will be invoked for every request. AFAICT there is nothing in that code that would differentiate requests (API vs UI requests) so add_stylesheet() will be called for all of them which then calls add_link() that evaluates req.chrome.

mentioned in ​BH:comment:3:ticket:330

[Olemis Lang]

(In [12508]) ThemeEnginePlugin : Do not access req.chrome while filtering requests if template = data = None ( refs #10748 )

[Ryan J Ollos]

I cleaned up the reference in your commit message :)

One minor, almost irrelevant comment that I'd like to get your thoughts on. ​PEP8 states: Comparisons to singletons like None should always be done with is or is not, never the equality operators.

So I was thinking that would suggest the following change:

if (template, data) != (None, None):

->

if (template, data) is not (None, None)

(I wish individual bullet points on PEP8 had anchors so that we could link to them individually. The section headings have anchors, but even for those the browser doesn't seem to jump to the right location [at least in Chrome 23, try: ​http://www.python.org/dev/peps/pep-0008/#id37, it should go Programming Recommendations section]).

[Olemis Lang]

Replying to rjollos:

[...]

So I was thinking that would suggest the following change:

if (template, data) != (None, None):

->

if (template, data) is not (None, None)

Bad idea , mainly because of this

>>> (None, None) is (None, None)
False

[...]

[Ryan J Ollos]

Ah, right, because in the latter case it will be testing if the two references are the same. Thanks for the clarification.

[Olemis Lang]

(In [12534]) ThemeEnginePlugin: [regression] Theme struct will be None if no theme configured or set to 'default' - refs #10748 fixes #10800

[Olemis Lang]

This is done. Please reopen if anything weird is detected .

[Olemis Lang]

(In [12540]) ThemeEnginePlugin: Let theme post-process requests while rendering error pages - after [12508] refs #10748 fixes #10809