[zope2-tracker] [Bug 246983] Re: Page Template: TALES string expr. unicode err.

[LeoRochael]

There is a relatively simple fix for this problem.

The last segment in the traceback above is caused by this small
zope.tales.expressions.StringExpr.__call__() method on
zope.tales-3.4.0-py2.6.egg/zope/tales/expressions.py:

    258     def __call__(self, econtext):
    259         vvals = []
    260         for var in self._vars:
    261             v = var(econtext)
    262             vvals.append(v)
    263         return self._expr % tuple(vvals)


The problem is that self._expr is always a unicode string on recent versions of Zope2, whereas "self._vars" is a list of PathExpr objects, and "v = var(econtext)" will return whatever type of objects the path expressions resolve, even 8-bit strings. Which means the line "return self._expr % tuple(vvals)" will always cause a UnicodeDecodingError if any of the values is a string with 8-bit chars (save for Python default encoding tricks).

If line 261 above is replaced by:

  v = econtext.evaluateText(var)

In Zope2 this will return a Unicode object using the unicode conflict
resolver registered with Zope2. In plain zope.tales, the
zope.tales.tales.Context.evaluateText() method converts the object to
unicode directly unless it is already a text-ish object (like a i18n
message), which I believe is what makes sense in the context of String
Expressions.

I can commit a fix with tests based on this solution.

-- 
Page Template: TALES string expr. unicode err.
https://bugs.launchpad.net/bugs/246983
You received this bug notification because you are a member of Zope 2
Developers, which is subscribed to Zope 2.