Failures with changed repeat syntax newer Zope/chameleon

[mauritsvanrees]

In Zope/templates/chameleon the repeat syntax has changed slightly. Apparently previously you had to call repeat['widget'].index() to get the index number, but now you directly get the integer without needing to call it.
See plone/plone.app.z3cform#116 for such a failure in plone.app.z3cform in a template that overrides a base template in z3c.form. And see plone/plone.app.z3cform#117 for the fix.

The base template in z3c.form has the same problem, as do several other templates:

$ ack repeat | ack index
browser/multi_hidden.pt:6:        define="key_widget python:view.key_widgets[repeat['widget'].index()];">
browser/multi_display.pt:25:         tal:define="key_widget python:view.key_widgets[repeat['widget'].index()];"
browser/multi_input.pt:12:         tal:define="key_widget python:view.key_widgets[repeat['widget'].index()];">

This is in z3c.form 3.7.0.
I have no time right now to fix it, only to create an issue.

[d-maurer]

Maurits van Rees wrote at 2020-8-21 13:49 -0700:

In Zope/templates/chameleon the repeat syntax has changed slightly. Apparently previously you had to call `repeat['widget'].index()` to get the index number, but now you directly get the integer without needing to call it. ... The base template in `z3c.form` has the same problem, as do several other templates: ``` $ ack repeat | ack index browser/multi_hidden.pt:6: define="key_widget python:view.key_widgets[repeat['widget'].index()];"> browser/multi_display.pt:25: tal:define="key_widget python:view.key_widgets[repeat['widget'].index()];" browser/multi_input.pt:12: tal:define="key_widget python:view.key_widgets[repeat['widget'].index()];"> ``` This is in `z3c.form` 3.7.0. I have no time right now to fix it, only to create an issue.

This is related to "zopefoundation/Zope#875". In short: `zope.tales` (for which `z3c.form` has been developed) defines a so called "Iterator" with methods; for `Zope` and even more `chameleon` some of those methods are redefined as (integer) properties -- introducing an incompatibilty between `Zope`/`chameleon` on one side and `zope.tales` on the other. To avoid problems created by those incompatibilities, it is best to access repeat variable metadata (managed by the above "Iterator"s) via path expressions which automatically call methods and thereby hide the method/property difference. For the cases above, `repeat['widget'].index()` could be replaced by `path('repeat/widget/index`).

[mauritsvanrees]

Thanks for your reaction.

That code is how I solve it too.