forms: do not consider fields from other pages for live sources (#68197)

tests/form_pages/test_live.py

@@ -101,6 +101,32 @@ def test_field_live_condition(pub):
     assert '<span class="label">Foo</span>' in resp.text
 
 
+def test_field_live_condition_on_other_page(pub):
+    FormDef.wipe()
+    formdef = FormDef()
+    formdef.name = 'Foo'
+    formdef.fields = [
+        fields.PageField(type='page', id='0', label='Page1'),
+        fields.StringField(type='string', id='1', label='Bar', size='40', required=True, varname='bar'),
+        fields.PageField(type='page', id='2', label='Page2'),
+        fields.StringField(
+            type='string',
+            id='3',
+            label='Foo',
+            size='40',
+            required=True,
+            varname='foo',
+            condition={'type': 'django', 'value': 'form_var_bar == "bye"'},
+        ),
+    ]
+    formdef.store()
+
+    app = get_app(pub)
+    resp = app.get(formdef.get_url())
+    assert 'f1' in resp.form.fields
+    assert 'data-live-source' not in resp.html.find('div', {'data-field-id': '1'}).attrs
+
+
 def test_field_live_items_condition(pub):
     FormDef.wipe()
     formdef = FormDef()

wcs/formdef.py

@@ -967,7 +967,13 @@ class FormDef(StorableObject):
     def set_live_condition_sources(self, form, fields):
         live_condition_fields = {}
 
+        fields_ids = {str(x.id) for x in fields}
+
         for field in self.iter_fields(include_block_fields=True):
+            if (hasattr(field, 'block_field') and str(field.block_field.id) not in fields_ids) or (
+                not hasattr(field, 'block_field') and str(field.id) not in fields_ids
+            ):
+                continue
             if field.condition:
                 field.varnames = field.get_condition_varnames(formdef=self)
                 for varname in field.varnames: