allow empty css variables

fixes Textualize#1849 Co-authored-by: @eliasdorneles
seifertm · Jul 22, 2023 · be52691 · be52691
1 parent abc745c
commit be52691
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diff --git a/src/textual/css/parse.py b/src/textual/css/parse.py
@@ -287,6 +287,8 @@ def substitute_references(
                     variables.setdefault(variable_name, []).append(token)
                     yield token
                 elif token.name == "variable_value_end":
+                    # in case of an empty variable, avoid not referenced error
+                    variables.setdefault(variable_name, [])
                     yield token
                     break
                 # For variables referring to other variables

diff --git a/tests/css/test_parse.py b/tests/css/test_parse.py
@@ -220,6 +220,22 @@ def test_undefined_variable(self):
         with pytest.raises(UnresolvedVariableError):
             list(substitute_references(tokenize(css, "")))
 
+    def test_empty_variable(self):
+        css = "$x:\n* { background:$x; }"
+        result = list(substitute_references(tokenize(css, "")))
+        assert [(t.name, t.value) for t in result] == [
+            ("variable_name", "$x:"),
+            ("variable_value_end", "\n"),
+            ("selector_start_universal", "*"),
+            ("whitespace", " "),
+            ("declaration_set_start", "{"),
+            ("whitespace", " "),
+            ("declaration_name", "background:"),
+            ("declaration_end", ";"),
+            ("whitespace", " "),
+            ("declaration_set_end", "}"),
+        ]
+
     def test_transitive_reference(self):
         css = "$x: 1\n$y: $x\n.thing { border: $y }"
         assert list(substitute_references(tokenize(css, ""))) == [