Evita padrões de sintaxe específicos do python 3

Evita a, *b = lista, entre outros padrões específicos do python 3.

Isso foi feito para que o código possa ser lido por ferramentas de
análise e manipulação de código que esperam a sintaxe do python 2.

Especificamente clonedigger e redbaron, que por enquanto não rodam em
python 3.

crispy_layout_mixin.py

@@ -8,6 +8,11 @@ from crispy_forms.layout import HTML, Div, Fieldset, Layout, Submit
 from django.utils.translation import ugettext as _
 
 
+def heads_and_tails(list_of_lists):
+    for alist in list_of_lists:
+        yield alist[0], alist[1:]
+
+
 def to_column(name_span):
     fieldname, span = name_span
     return Div(fieldname, css_class='col-md-%d' % span)
@@ -20,7 +25,7 @@ def to_row(names_spans):
 def to_fieldsets(fields):
     for field in fields:
         if isinstance(field, list):
-            legend, *row_specs = field
+            legend, row_specs = field[0], field[1:]
             rows = [to_row(name_span_list) for name_span_list in row_specs]
             yield Fieldset(legend, *rows)
         else:
@@ -103,12 +108,13 @@ class CrispyLayoutFormMixin(object):
 
     @property
     def layout_display(self):
+
         return [
             {'legend': legend,
              'rows': [[self.get_column(fieldname, span)
                        for fieldname, span in row]
                       for row in rows]
-             } for legend, *rows in self.get_layout()]
+             } for legend, rows in heads_and_tails(self.get_layout())]
 
 
 def read_yaml_from_file(filename):

crud_tests/test_flux.py

@@ -212,7 +212,8 @@ def test_flux_list_paginate_detail(
             assert_on_list_page(res)
             table = res.html.find('table')
             assert table
-            header, *trs = table.findAll('tr')
+            header_trs = table.findAll('tr')
+            header, trs = header_trs[0], header_trs[1:]
             assert [c.text for c in header.findChildren('th')] == [
                 'name', 'continent', 'population', 'is cold']
             rows = [[td.text.strip() for td in tr.findAll('td')]

legacy/scripts/scrap_original_forms.py

@@ -9,6 +9,7 @@ from bs4 import BeautifulSoup
 from bs4.element import NavigableString, Tag
 from django.apps.config import AppConfig
 
+from crispy_layout_mixin import heads_and_tails
 from legacy.migration import appconfs, get_renames
 from legacy.scripts.utils import getsourcelines
 from sapl.utils import listify
@@ -274,7 +275,7 @@ class %(name)sForm(forms.ModelForm):
         self.helper.layout = SaplFormLayout(
 """ % {'name': model.__name__})
 
-        for legend, *rows in fieldsets:
+        for legend, rows in heads_and_tails(fieldsets):
             lines = pretty_printer.pformat([Under(legend)] + rows) + ',\n\n'
             for line in lines.splitlines():
                 print(' ' * GAP + line if line.strip() else '')

sapl/test_general.py

@@ -19,4 +19,4 @@ def test_str_sanity():
             except Exception as exc:
                 msg = '%s.%s.__str__ is broken.' % (
                     model.__module__, model.__name__)
-                raise AssertionError(msg, exc) from exc
+                raise AssertionError(msg, exc)