New branch to fix TAL default handling (#853)

* - new branch to fix TAL default handling

* adapt to changed default handling of `chameleon==3.7.4` (does not yet work

* Python 3 compatibility

* - use Chameleon 3.8

* Adaptations for `chameleon>=3.8`

* - fix lint issue

* - add test for straight boolean after seeing malthe/chameleon#318

* - comment change [ci skip]

Co-authored-by: dieter <dieter@handshake.de>

constraints.txt

@@ -2,7 +2,7 @@ AccessControl==4.2
 Acquisition==4.6
 AuthEncoding==4.1
 BTrees==4.6.1
-Chameleon==3.7.2
+Chameleon==3.8.0
 DateTime==4.3
 DocumentTemplate==3.2.3
 ExtensionClass==4.4

requirements-full.txt

@@ -3,7 +3,7 @@ AccessControl==4.2
 Acquisition==4.6
 AuthEncoding==4.1
 BTrees==4.6.1
-Chameleon==3.7.2
+Chameleon==3.8.0
 DateTime==4.3
 DocumentTemplate==3.2.3
 ExtensionClass==4.4

src/Products/PageTemplates/engine.py

@@ -18,6 +18,7 @@
 from chameleon.codegen import template
 from chameleon.exc import ExpressionError
 from chameleon.tal import RepeatDict
+from chameleon.tales import DEFAULT_MARKER  # only in chameleon 3.8.0 and up
 from chameleon.zpt.template import Macros
 
 from AccessControl.class_init import InitializeClass
@@ -288,19 +289,6 @@ class ZtPageTemplate(ChameleonPageTemplate):
     but it does not hurt to use the fixed value to represent ``default``
     rather than a template specific value.
     """
-    # override to get the proper ``zope.tales`` default marker
-    def _compile(self, body, builtins):
-        code = super(ZtPageTemplate, self)._compile(body, builtins)
-        # redefine ``__default`` as ``zope.tales.tales._default``
-        #  Potentially this could be simpler
-        frags = code.split("\n", 5)
-        for i, frag in enumerate(frags[:-1]):
-            if frag.startswith("__default = "):
-                frags[i] = "from zope.tales.tales import _default as __default"
-                break
-        else:
-            raise RuntimeError("unexpected code prelude %s" % frags[:-1])
-        return "\n".join(frags)
 
     # use `chameleon` configuration to obtain more
     # informative error information
@@ -329,15 +317,7 @@ def __call__(self, context, macros, tal=True, **options):
         kwargs["__zt_context__"] = context
 
         template = self.template
-        # work around ``https://github.com/zopefoundation/Zope/issues/846``
-        template.cook_check()  # ensure `_render` is computed
-        rf = getattr(template, "_render", None)
-        if rf is not None:
-            defs = [c for c in rf.__code__.co_consts if c == '__default']
-            if len(defs) == 1:
-                # use the template's private ``default`` representation
-                # as our TALES ``default`` value
-                kwargs["default"] = defs[0]
+        kwargs["default"] = DEFAULT_MARKER
 
         return template.render(**kwargs)
 

src/Products/PageTemplates/tests/input/BooleanAttributes.html

@@ -0,0 +1,7 @@
+<select>
+  <option value="" tal:attributes="selected python: True">Selected</option>
+  <option value="a" tal:attributes="selected python: False">Not selected</option>
+  <option value="ok" tal:attributes="selected python: None">Not selected</option>
+  <option value="b" tal:attributes="selected nothing">Not selected</option>
+  <option value="c" tal:attributes="selected string:">Not selected</option>
+</select>

src/Products/PageTemplates/tests/input/Default.html

@@ -4,5 +4,7 @@
 <p tal:define="foo string:"
    tal:content="python: foo or default">Default in Python expression</p>
 <p tal:content="context/I_Fail|default">Default in Path expression</p>
+<p><span tal:replace="default">Default in replace</span></p>
+<p attr="attribute default" tal:attributes="attr default"></p>
 </body>
 </html>

src/Products/PageTemplates/tests/output/BooleanAttributes.html

@@ -0,0 +1,7 @@
+<select>
+  <option value="" selected="selected">Selected</option>
+  <option value="a">Not selected</option>
+  <option value="ok">Not selected</option>
+  <option value="b">Not selected</option>
+  <option value="c">Not selected</option>
+</select>

src/Products/PageTemplates/tests/output/Default.html

@@ -3,5 +3,7 @@
 <body>
 <p>Default in Python expression</p>
 <p>Default in Path expression</p>
+<p><span>Default in replace</span></p>
+<p attr="attribute default"></p>
 </body>
 </html>

src/Products/PageTemplates/tests/testHTMLTests.py

@@ -169,6 +169,11 @@ def testImportOldStyleClass(self):
     def testRepeatVariable(self):
         self.assert_expected(self.folder.t, 'RepeatVariable.html')
 
+    def testBooleanAttributes(self):
+        # Test rendering an attribute that should be empty or left out
+        # if the value is non-True
+        self.assert_expected(self.folder.t, 'BooleanAttributes.html')
+
     def testBooleanAttributesAndDefault(self):
         # Zope 2.9 and below support the semantics that an HTML
         # "boolean" attribute (e.g. 'selected', 'disabled', etc.) can

versions-prod.cfg

@@ -8,7 +8,7 @@ AccessControl = 4.2
 Acquisition = 4.6
 AuthEncoding = 4.1
 BTrees = 4.6.1
-Chameleon = 3.7.2
+Chameleon = 3.8.0
 DateTime = 4.3
 DocumentTemplate = 3.2.3
 ExtensionClass = 4.4