Fix missing terms for sources

Version 2.9 introduced a solution for missing terms in vocabularies.
Adapted sources to this solution, too.

CHANGES.txt

@@ -13,6 +13,9 @@ CHANGES
   when trying to remove from ignored list. Probably not the 100%
   right fix but it catches core dumps and is sane anyways.
 
+- Version 2.9 introduced a solution for missing terms in
+  vocabularies. Adapted sources to this solution, too.
+
 
 3.0.0a3 (2013-04-08)
 --------------------

src/z3c/form/term.py

@@ -16,8 +16,9 @@
 $Id$
 """
 
-import zope.browser
+import zope.browser.interfaces
 import zope.component
+import zope.interface
 import zope.schema
 from zope.schema import vocabulary
 
@@ -64,12 +65,19 @@ def __init__(self, context, request, form, field, source, widget):
             (self.source, self.request),
             zope.browser.interfaces.ITerms)
 
+    def getTerm(self, value):
+        try:
+            return super(SourceTerms, self).getTerm(value)
+        except KeyError:
+            raise LookupError(value)
+
     def getTermByToken(self, token):
         # This is rather expensive
         for value in self.source:
             term = self.getTerm(value)
             if term.token == token:
                 return term
+        raise LookupError(token)
 
     def getValue(self, token):
         return self.terms.getValue(token)
@@ -128,7 +136,7 @@ class MissingTermsMixin(object):
 
     def getTerm(self, value):
         try:
-            return self.terms.getTerm(value)
+            return super(MissingTermsMixin, self).getTerm(value)
         except LookupError:
             if (interfaces.IContextAware.providedBy(self.widget) and
                 not self.widget.ignoreContext):
@@ -153,7 +161,7 @@ def _makeMissingTerm(self, value):
 
     def getTermByToken(self, token):
         try:
-            return self.terms.getTermByToken(token)
+            return super(MissingTermsMixin, self).getTermByToken(token)
         except LookupError:
             if (interfaces.IContextAware.providedBy(self.widget) and
                 not self.widget.ignoreContext):
@@ -188,6 +196,11 @@ class ChoiceTermsSource(SourceTerms):
         interfaces.IWidget)
 
 
+class MissingChoiceTermsSource(MissingTermsMixin, ChoiceTermsSource):
+    """ITerms adapter for zope.schema.IChoice based implementations using source
+       with missing terms support."""
+
+
 @zope.interface.implementer_only(interfaces.IBoolTerms)
 class BoolTerms(Terms):
     """Default yes and no terms are used by default for IBool fields."""
@@ -267,3 +280,8 @@ class CollectionTermsSource(SourceTerms):
         zope.schema.interfaces.ICollection,
         zope.schema.interfaces.IIterableSource,
         interfaces.IWidget)
+
+
+class MissingCollectionTermsSource(MissingTermsMixin, CollectionTermsSource):
+    """ITerms adapter for zope.schema.ICollection based implementations using
+    source with missing terms support."""

src/z3c/form/term.txt

@@ -343,6 +343,90 @@ With can test if a value is in the source:
   >>> 25 in terms
   False
 
+Missing terms
+#############
+
+Sometimes it happens that a value goes away from the source, but our
+stored objects still has this value.
+
+  >>> zope.component.provideAdapter(term.MissingChoiceTermsSource)
+
+  >>> terms = term.ChoiceTerms(
+  ...     None, request, None, sourceRatingField, widget)
+  >>> terms.getTermByToken('42')
+  Traceback (most recent call last):
+  ...
+  LookupError: 42
+
+The same goes with looking up a term by value:
+
+  >>> terms.getTerm('42')
+  Traceback (most recent call last):
+  ...
+  LookupError: 42
+
+Ooops, well this works only if the context has the right value for us.
+This is because we don't want to accept any crap that's coming from HTML.
+
+  >>> class IRating(zope.interface.Interface):
+  ...     rating = zope.schema.Choice(title=u'Sourced Rating',
+  ...                                 source=RatingSourceFactory())
+  >>> @zope.interface.implementer(IRating)
+  ... class Rating(object):
+  ...     rating = None
+
+  >>> ctx = Rating()
+  >>> ctx.rating = 42
+
+  >>> ratingWidget = z3c.form.widget.Widget(request)
+  >>> ratingWidget.context = ctx
+  >>> from z3c.form import interfaces
+  >>> zope.interface.alsoProvides(ratingWidget, interfaces.IContextAware)
+  >>> from z3c.form.datamanager import AttributeField
+  >>> zope.component.provideAdapter(AttributeField)
+
+  >>> terms = term.ChoiceTerms(
+  ...     ctx, request, None, IRating['rating'], ratingWidget)
+
+Here we go:
+
+  >>> missingTerm = terms.getTermByToken('42')
+
+We get the term, we passed the token, the value is coming from the context.
+
+  >>> missingTerm.token
+  '42'
+  >>> missingTerm.value
+  42
+
+We cannot figure the title, so we construct one.
+Override ``makeMissingTerm`` if you want your own.
+
+  >>> missingTerm.title
+  u'Missing: ${value}'
+
+Still we raise LookupError if the token does not fit the context's value:
+
+  >>> missingTerm = terms.getTermByToken('99')
+  Traceback (most recent call last):
+  ...
+  LookupError: 99
+
+The same goes with looking up a term by value.
+We get the term if the context's value fits:
+
+  >>> missingTerm = terms.getTerm(42)
+  >>> missingTerm.token
+  '42'
+
+And an exception if it does not:
+
+  >>> missingTerm = terms.getTerm(99)
+  Traceback (most recent call last):
+  ...
+  LookupError: 99
+
+
 Collections
 +++++++++++
 

src/z3c/form/term.zcml

@@ -10,7 +10,7 @@
       factory=".term.MissingChoiceTermsVocabulary"
       />
   <adapter
-      factory=".term.ChoiceTermsSource"
+      factory=".term.MissingChoiceTermsSource"
       />
   <adapter
       factory=".term.CollectionTerms"

src/z3c/form/tests/test_doc.py

@@ -128,6 +128,11 @@ def test_suite():
             setUp=setUp, tearDown=testing.tearDown,
             optionflags=flags, checker=testing.outputChecker,
             ),
+        doctest.DocFileSuite(
+            '../term.txt',
+            setUp=setUp, tearDown=testing.tearDown,
+            optionflags=flags, checker=testing.outputChecker,
+            ),
         doctest.DocFileSuite(
             '../util.txt',
             setUp=setUp, tearDown=testing.tearDown,