sadpandajoe commented on code in PR #45271:
URL: https://github.com/apache/superset/pull/45271#discussion_r4353679614
##########
superset/sql/parse.py:
##########
@@ -268,6 +268,33 @@ def has_aggregate(
)
+def is_constant_expression(expression: str, engine: str = "base") -> bool:
+ """
+ Return True if the SQL expression is a bare constant: a string or numeric
+ literal, ``NULL``, or (outside SQLite) a boolean literal, optionally
wrapped
+ in parentheses.
+
+ Anything that merely contains a constant (``CASE WHEN 1=1 THEN 'x' END``,
+ ``CAST('x' AS VARCHAR)``, ``'a' || col``) is not a bare constant. Fails
closed
+ (returns False) on a parse error, so an expression that can't be proven
+ constant is never treated as one.
+
+ ``TRUE``/``FALSE`` are not bare constants on SQLite: they are ordinary
+ identifiers there, resolved to a column of that name when one exists.
+ """
+ dialect = SQLGLOT_DIALECTS.get(engine)
+ try:
+ parsed = sqlglot.parse_one(f"SELECT {expression}", dialect=dialect)
+ except Exception:
+ return False
+ if not isinstance(parsed, exp.Select) or len(parsed.expressions) != 1:
+ return False
+ node = parsed.expressions[0].unnest()
+ if isinstance(node, exp.Boolean):
+ return dialect != Dialects.SQLITE
+ return isinstance(node, (exp.Literal, exp.Null))
Review Comment:
Update: I rebased the branch onto current master (it was behind, which broke
an unrelated required e2e step). The patch is unchanged; this fix is now
0e34933 (was ef2a16b).
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