templatetags: correct add filter (#42650)

combo/public/templatetags/combo.py

@@ -465,14 +465,18 @@ def decimal(value, arg=None):
 def add(term1, term2):
     '''replace the "add" native django filter'''
 
+    if term1 is None:
+        term1 = ''
+    if term2 is None:
+        term2 = ''
     term1_decimal = parse_decimal(term1, default=None)
     term2_decimal = parse_decimal(term2, default=None)
 
     if term1_decimal is not None and term2_decimal is not None:
         return term1_decimal + term2_decimal
-    if not term1 and term2_decimal is not None:
+    if term1 == '' and term2_decimal is not None:
         return term2_decimal
-    if not term2 and term1_decimal is not None:
+    if term2 == '' and term1_decimal is not None:
         return term1_decimal
     return defaultfilters.add(term1, term2)
 

tests/test_public_templatetags.py

@@ -567,6 +567,12 @@ def test_mathematics_templatetag():
     assert tmpl.render(Context({'term1': '', 'term2': 0})) == '0'
     assert tmpl.render(Context({'term1': 0, 'term2': 0})) == '0'
 
+    # if term is '' or None and other term is decimal
+    assert tmpl.render(Context({'term1': '', 'term2': 2.2})) == '2.2'
+    assert tmpl.render(Context({'term1': None, 'term2': 2.2})) == '2.2'
+    assert tmpl.render(Context({'term1': 2.2, 'term2': ''})) == '2.2'
+    assert tmpl.render(Context({'term1': 2.2, 'term2': None})) == '2.2'
+
     # add using ',' instead of '.' decimal separator
     assert tmpl.render(Context({'term1': '1,1', 'term2': '2,2'})) == '3.3'
     assert tmpl.render(Context({'term1': '1,1', 'term2': '2.2'})) == '3.3'
@@ -624,6 +630,23 @@ def test_mathematics_templatetag():
     assert tmpl.render(Context({'term1': 2, 'term2': 3})) == '0.67'
 
 
+def test_concatenation_templatetag():
+    tmpl = Template('{{ term1|add:term2 }}')
+
+    # fallback to Django native add filter
+    assert tmpl.render(Context({'term1': 'foo', 'term2': 'bar'})) == 'foobar'
+    assert tmpl.render(Context({'term1': 'foo', 'term2': ''})) == 'foo'
+    assert tmpl.render(Context({'term1': 'foo', 'term2': None})) == 'foo'
+    assert tmpl.render(Context({'term1': 'foo', 'term2': 0})) == ''
+    assert tmpl.render(Context({'term1': '', 'term2': 'bar'})) == 'bar'
+    assert tmpl.render(Context({'term1': '', 'term2': ''})) == ''
+    assert tmpl.render(Context({'term1': '', 'term2': None})) == ''
+    assert tmpl.render(Context({'term1': None, 'term2': 'bar'})) == 'bar'
+    assert tmpl.render(Context({'term1': None, 'term2': ''})) == ''
+    assert tmpl.render(Context({'term1': None, 'term2': None})) == ''
+    assert tmpl.render(Context({'term1': 0, 'term2': 'bar'})) == ''
+
+
 def test_rounding_templatetag():
     # ceil
     tmpl = Template('{{ value|ceil }}')