templatetags: beautify decimal filter's code (#30852)

tests/test_templates.py

@@ -286,20 +286,20 @@ def test_variable_unicode_error_handling():
 
 def test_decimal_templatetag():
     tmpl = Template('{{ plop|decimal }}')
-    assert tmpl.render({'plop': 'toto'}) == ''
+    assert tmpl.render({'plop': 'toto'}) == '0'
     assert tmpl.render({'plop': '3.14'}) == '3.14'
     assert tmpl.render({'plop': '3,14'}) == '3.14'
     assert tmpl.render({'plop': 3.14}) == '3.14'
     assert tmpl.render({'plop': 12345.678}) == '12345.678'
-    assert tmpl.render({'plop': None}) == ''
+    assert tmpl.render({'plop': None}) == '0'
     assert tmpl.render({'plop': 0}) == '0'
 
     tmpl = Template('{{ plop|decimal:3 }}')
     assert tmpl.render({'plop': '3.14'}) == '3.140'
-    assert tmpl.render({'plop': None}) == ''
+    assert tmpl.render({'plop': None}) == '0.000'
     tmpl = Template('{{ plop|decimal:"3" }}')
     assert tmpl.render({'plop': '3.14'}) == '3.140'
-    assert tmpl.render({'plop': None}) == ''
+    assert tmpl.render({'plop': None}) == '0.000'
 
     tmpl = Template('{% if plop|decimal > 2 %}hello{% endif %}')
     assert tmpl.render({'plop': 3}) == 'hello'
@@ -309,8 +309,9 @@ def test_decimal_templatetag():
     assert tmpl.render({'plop': 1}) == ''
     assert tmpl.render({'plop': 1.99}) == ''
     assert tmpl.render({'plop': '1.99'}) == ''
-    assert tmpl.render({'plop': 'x'}) == 'hello'
-    assert tmpl.render({'plop': None}) == 'hello'  # will be str > int, always True.
+    assert tmpl.render({'plop': 'x'}) == ''
+    assert tmpl.render({'plop': None}) == ''
+    assert tmpl.render({'plop': 0}) == ''
 
     tmpl = Template('{% if "3"|decimal == 3 %}hello{% endif %}')
     assert tmpl.render() == 'hello'

wcs/qommon/templatetags/qommon.py

@@ -112,26 +112,24 @@ def time(value, arg=None):
     return defaultfilters.date(value, arg=arg)
 
 def parse_decimal(value):
+    if hasattr(value, 'get_value'):
+        value = value.get_value()  # unlazy
     if isinstance(value, basestring):
         # replace , by . for French users comfort
         value = value.replace(',', '.')
     try:
         return Decimal(value).quantize(Decimal('1.0000')).normalize()
     except (ArithmeticError, TypeError):
-        return None
+        return Decimal(0)
 
 @register.filter(is_safe=False)
 def decimal(value, arg=None):
-    if hasattr(value, 'get_value'):
-        value = value.get_value()  # unlazy
     if not isinstance(value, Decimal):
         value = parse_decimal(value)
-    if value is None:
-        return ''
-    if hasattr(arg, 'get_value'):
-        arg = arg.get_value()  # unlazy
     if arg is None:
         return value
+    if hasattr(arg, 'get_value'):
+        arg = arg.get_value()  # unlazy
     return defaultfilters.floatformat(value, arg=arg)
 
 @register.filter(expects_localtime=True, is_safe=False)