fields: make "live" values available as form_var_xxx in page conditions (#7489)

help/fr/form-multipages.page

@@ -64,7 +64,7 @@ trouvent pas à <em>flotter</em> en-dehors de la structure de pages.
    <code>mode_de_transport</code>, la page sur l'accès au parking ne devrait
    pas être affichée pour les personnes ayant précisés qu'elles venaient à
    pieds, le champ serait complété avec l'expression suivante :
-   <code>var_mode_de_transport != "Piéton"</code> (où le <code>!=</code>
+   <code>form_var_mode_de_transport != "Piéton"</code> (où le <code>!=</code>
    correspond à la syntaxe Python signifiant « différent de »).
   </p>
 

tests/test_form_pages.py

@@ -258,6 +258,36 @@ def test_form_multi_page_condition_select(pub):
     assert '3rd page' in resp.body
     assert '<li class="current"><span>3rd page</span>' in resp.body
 
+def test_form_multi_page_condition_select_new_varname(pub):
+    formdef = create_formdef()
+    formdef.fields = [fields.PageField(id='0', label='1st page', type='page'),
+            fields.ItemField(id='1', label='select', type='item',
+                required=True,
+                varname='foo', items=['Foo', 'Bar']),
+            fields.PageField(id='2', label='2nd page', type='page',
+                condition='form_var_foo == "Foo"'),
+            fields.PageField(id='3', label='3rd page', type='page',
+                condition='form_var_foo == "Bar"'),
+            fields.StringField(id='3', label='string 2')]
+    formdef.store()
+    formdef.data_class().wipe()
+    resp = get_app(pub).get('/test/')
+    assert not '2nd page' in resp.body
+    assert not '3rd page' in resp.body
+    resp.forms[0]['f1'] = 'Foo'
+    resp = resp.forms[0].submit('submit')
+    assert '2nd page' in resp.body
+    assert not '3rd page' in resp.body
+    assert '<li class="current"><span>2nd page</span>' in resp.body
+
+    resp = get_app(pub).get('/test/')
+    resp.forms[0]['f1'] = 'Bar'
+    resp = resp.forms[0].submit('submit')
+    assert not '2nd page' in resp.body
+    assert '3rd page' in resp.body
+    assert '<li class="current"><span>3rd page</span>' in resp.body
+
+
 def test_form_submit_with_user(pub):
     create_user(pub)
     formdef = create_formdef()

wcs/fields.py

@@ -1135,8 +1135,17 @@ class PageField(Field):
             return True
 
         from formdata import get_dict_with_varnames
-        data = get_dict_with_varnames(formdef.fields, dict)
-        data.update(get_publisher().substitutions.get_context_variables())
+        data = get_publisher().substitutions.get_context_variables()
+
+        # create variables with values currently being evaluated, not yet
+        # available in the formdata
+        dict_with_varnames = get_dict_with_varnames(formdef.fields, dict)
+        # add them as var_xxx for compatibility
+        data.update(dict_with_varnames)
+        # and add them as form_var_xxx, overriding context variables with their
+        # "live" value
+        for k, v in dict_with_varnames.items():
+            data['form_' + k] = v
 
         try:
             if eval(self.condition, get_publisher().get_global_eval_dict(), data):