From 8cc7e1a819081a9e279cbaa0f72749893d181d99 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20P=C3=A9ters?= <fpeters@entrouvert.com>
Date: Wed, 11 Jul 2018 10:30:25 +0200
Subject: [PATCH] forms: make sure latest live data are used to evaluate
 conditions (#25197)

---
 tests/test_form_pages.py | 41 ++++++++++++++++++++++++++++++++++++++++
 wcs/fields.py            | 16 +++++++++-------
 wcs/forms/root.py        |  6 +++++-
 3 files changed, 55 insertions(+), 8 deletions(-)

diff --git a/tests/test_form_pages.py b/tests/test_form_pages.py
index 5566035d..68ba22a5 100644
--- a/tests/test_form_pages.py
+++ b/tests/test_form_pages.py
@@ -993,6 +993,47 @@ def test_form_multi_page_post_conditions(pub):
     resp = resp.forms[0].submit('submit')
     assert 'Check values then click submit.' in resp.body
 
+def test_form_multi_page_conditions_and_post_conditions(pub):
+    formdef = create_formdef()
+    formdef.fields = [
+        fields.PageField(id='0', label='1st page', type='page',
+            post_conditions=[{
+                'condition': {'type': 'python', 'value': 'form_var_bar == "bar"'},
+                'error_message': 'You shall not pass.'}]),
+        fields.StringField(id='1', label='string', varname='bar'),
+        fields.PageField(id='3', label='2nd page', type='page'),
+    ]
+
+    formdef.store()
+    formdef.data_class().wipe()
+
+    resp = get_app(pub).get('/test/')
+    resp.form['f1'] = 'bar'
+    resp = resp.form.submit('submit')
+    assert_current_page(resp, '2nd page')
+
+    resp = get_app(pub).get('/test/')
+    resp.form['f1'] = 'foo'
+    resp = resp.form.submit('submit')
+    assert 'You shall not pass.' in resp.body
+
+    # add a conditional page, this will cause pages to be evaluated first
+    # (and would trigger #25197)
+    formdef.fields.append(
+        fields.PageField(id='4', label='3rd page', type='page',
+            condition={'type': 'python', 'value': 'True'}))
+    formdef.store()
+
+    resp = get_app(pub).get('/test/')
+    resp.form['f1'] = 'bar'
+    resp = resp.form.submit('submit')
+    assert_current_page(resp, '2nd page')
+
+    resp = get_app(pub).get('/test/')
+    resp.form['f1'] = 'foo'
+    resp = resp.form.submit('submit')
+    assert 'You shall not pass.' in resp.body
+
 def test_form_multi_page_page_name_as_title(pub):
     formdef = create_formdef()
     formdef.fields = [fields.PageField(id='0', label='1st page', type='page'),
diff --git a/wcs/fields.py b/wcs/fields.py
index 156e4be8..52d67148 100644
--- a/wcs/fields.py
+++ b/wcs/fields.py
@@ -1501,22 +1501,24 @@ class PageCondition(Condition):
         # they will shadow formdata context variables with their new "live"
         # value, this may be useful when evaluating data sources.
         class ConditionVars(object):
+            def __init__(self, id_dict_var):
+                # keep track of reference dictionary
+                self.id_dict_var = id_dict_var
+
             def get_substitution_variables(self):
                 return form_live_data
 
             def __eq__(self, other):
-                # Assume all ConditionVars are equal (as they are because they
-                # are created using the same live data); this avoids filling
+                # Assume all ConditionVars are equal when initialized with
+                # the same live data dictionary; this avoids filling
                 # the substitution sources with duplicates and invalidating its
                 # cache.
-                try:
-                    return self.__class__.__name__ == other.__class__.__name__
-                except AttributeError:
-                    return False
+                return self.id_dict_var == getattr(other, 'id_dict_var', None)
+
         if dict_vars is not None:
             # Add them only if there is a real dict_vars in context,
             # ie do nothing on first page condition
-            get_publisher().substitutions.feed(ConditionVars())
+            get_publisher().substitutions.feed(ConditionVars(id(dict_vars)))
 
         data = get_publisher().substitutions.get_context_variables()
         # 2) add live data as var_ variables for local evaluation only, for
diff --git a/wcs/forms/root.py b/wcs/forms/root.py
index cc27d678..24af84ab 100644
--- a/wcs/forms/root.py
+++ b/wcs/forms/root.py
@@ -14,6 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, see <http://www.gnu.org/licenses/>.
 
+import copy
 import json
 import time
 from StringIO import StringIO
@@ -718,7 +719,10 @@ class FormPage(Directory, FormTemplateMixin):
             page_error_messages = []
             if form.get_submit() == 'submit' and page:
                 post_conditions = page.post_conditions or []
-                form_data = session.get_by_magictoken(magictoken, {})
+                # create a new dictionary to hold live data, this makes sure
+                # a new ConditionsVars will get added to the substitution
+                # variables.
+                form_data = copy.copy(session.get_by_magictoken(magictoken, {}))
                 data = self.formdef.get_data(form)
                 form_data.update(data)
                 for i, post_condition in enumerate(post_conditions):
-- 
2.18.0