fixed validation bug

bel/lang/ast.py

@@ -1340,6 +1340,18 @@ def validate_function(fn: Function, errors: List[ValidationError] = None) -> Lis
                             index=fn.args[position].span.start,
                         )
                     )
+    # Sixth pass - non-positional StrArgs are errors
+    for idx, arg in enumerate(fn.args):
+        if arg.type == "StrArg" and signature["arguments"][idx]["position"] is None:
+            errors.append(
+                ValidationError(
+                    type="Assertion",
+                    severity="Error",
+                    msg="String argument not allowed as an optional or multiple argument. Probably missing a namespace.",
+                    visual_pairs=[(arg.span.start, arg.span.end)],
+                    index=arg.span.start,
+                )
+            )
 
     # Check for obsolete namespaces
     for arg in fn.args:

tests/lang/test_ast.py

@@ -194,6 +194,20 @@ def test_validate_missing_namespace():
     assert ast.errors[0].severity == "Warning"
 
 
+def test_validate_strarg():
+
+    assertion = AssertionStr(subject='complex("missing")')
+    expected = ""
+
+    ast = bel.lang.ast.BELAst(assertion=assertion)
+
+    ast.validate()
+
+    print("Errors", ast.errors)
+
+    assert ast.errors[0].msg == expected
+
+
 def test_validate_empty_function():
     """Validate empty function"""