Improve performance when using condition_dict

formtools/wizard/views.py

@@ -209,9 +209,18 @@ def get_form_list(self):
         and respect the result. (True means add the form, False means ignore
         the form)
 
-        The form_list is always generated on the fly because condition methods
-        could use data from other (maybe previous forms).
+        The form_list is generated once per wizard instance to avoid repeated
+        expensive condition evaluations (e.g., database queries).
         """
+        # Check if condition_dict has been modified since last resolution
+        condition_dict_signature = (
+            id(self.condition_dict),
+            tuple(sorted(self.condition_dict.items())),
+        )
+        if (hasattr(self, '_resolved_form_list') and
+            self._condition_dict_signature == condition_dict_signature):
+            return self._resolved_form_list
+
         form_list = OrderedDict()
         if getattr(self, '_check_cond_started', False):
             # Guard against infinite recursion, in the case a get_form_list is
@@ -228,6 +237,8 @@ def get_form_list(self):
             if condition:
                 form_list[form_key] = form_class
         del self._check_cond_started
+        self._resolved_form_list = form_list
+        self._condition_dict_signature = condition_dict_signature
         return form_list
 
     def dispatch(self, request, *args, **kwargs):
@@ -301,6 +312,12 @@ def post(self, *args, **kwargs):
             # if the form is valid, store the cleaned data and files.
             self.storage.set_step_data(self.steps.current, self.process_step(form))
             self.storage.set_step_files(self.steps.current, self.process_step_files(form))
+            # Clear caches as changed step data could affect conditions
+            del self._resolved_form_list
+            del self._condition_dict_signature
+            for attr_name in list(self.__dict__.keys()):
+                if attr_name.startswith('_cleaned_data_cache_'):
+                    delattr(self, attr_name)
 
             # check if the current step is the last step
             if self.steps.current == self.steps.last:
@@ -497,13 +514,20 @@ def get_cleaned_data_for_step(self, step):
         If the data doesn't validate, None will be returned.
         """
         if step in self.form_list:
+            cache_key = f'_cleaned_data_cache_{step}'
+            if cached_data := getattr(self, cache_key, None):
+                return cached_data
             form_obj = self.get_form(
                 step=step,
                 data=self.storage.get_step_data(step),
                 files=self.storage.get_step_files(step),
             )
             if form_obj.is_valid():
-                return form_obj.cleaned_data
+                cleaned_data = form_obj.cleaned_data
+                setattr(self, cache_key, cleaned_data)
+                return cleaned_data
+            else:
+                setattr(self, cache_key, None)
         return None
 
     def get_next_step(self, step=None):

tests/wizard/test_forms.py

@@ -179,6 +179,32 @@ def subsequent_step_check(wizard):
         finally:
             sys.setrecursionlimit(old_limit)
 
+    def test_form_initial_multiple_calls_regression(self):
+        def step2_condition(wizard):
+            wizard.get_cleaned_data_for_step('start')
+            return True
+
+        class TestWizardWithTracking(TestWizard):
+            condition_dict = {'step2': step2_condition}
+            initial_call_count = 0
+
+            def get_form_initial(self, step):
+                self.initial_call_count += 1
+                return super().get_form_initial(step)
+
+        testform = TestWizardWithTracking.as_view(
+            [('start', Step1), ('step2', Step2)]
+        )
+        request = get_request(
+            {
+                'test_wizard_with_tracking-current_step': 'start',
+                'start-name': 'test'
+            }
+        )
+        response, instance = testform(request)
+        calls_during_submission = instance.initial_call_count
+        self.assertLessEqual(calls_during_submission, 4)
+
     def test_form_condition_unstable(self):
         request = get_request()
         testform = TestWizard.as_view(