fix: resolve SET/SHOW option names from unquoted identifiers

SET "query.parallelism" = 4 previously succeeded without taking effect:
ObjectName::to_string() keeps the quotes, so the name never matched the
known query options and fell through to the unknown-setting compatibility
branch, bypassing validation of invalid values such as 0.

Resolve the option name from the parsed identifier values
(object_name_to_string_unquoted) for both SET and SHOW so quoted and
unquoted spellings behave identically.

Signed-off-by: discord9 <55937128+discord9@users.noreply.github.com>

src/operator/src/statement.rs

@@ -527,7 +527,8 @@ impl StatementExecutor {
     }
 
     fn set_variables(&self, set_var: SetVariables, query_ctx: QueryContextRef) -> Result<Output> {
-        let var_name = set_var.variable.to_string().to_uppercase();
+        let variable = sql::ast::object_name_to_string_unquoted(&set_var.variable);
+        let var_name = variable.to_uppercase();
 
         debug!(
             "Trying to set {}={} for session: {} ",
@@ -536,11 +537,7 @@ impl StatementExecutor {
             query_ctx.conn_info()
         );
 
-        if set_query_option(
-            &set_var.variable.to_string(),
-            set_var.value.clone(),
-            query_ctx.clone(),
-        )? {
+        if set_query_option(&variable, set_var.value.clone(), query_ctx.clone())? {
             return Ok(Output::new_with_affected_rows(0));
         }
 

src/query/src/sql.rs

@@ -850,7 +850,7 @@ pub fn show_query_option(
     query_ctx: QueryContextRef,
     engine: &dyn crate::QueryEngine,
 ) -> Result<Option<Output>> {
-    let name = stmt.variable.to_string();
+    let name = sql::ast::object_name_to_string_unquoted(&stmt.variable);
     let Some(canonical) = session::query_options::canonical_query_option_name(&name) else {
         if name.to_ascii_lowercase().starts_with("query.")
             || name.to_ascii_lowercase().starts_with("datafusion.")

src/sql/src/ast.rs

@@ -32,3 +32,37 @@ impl ObjectNamePartExt for ObjectNamePart {
         ident.value.clone()
     }
 }
+
+/// Formats an object name by joining its identifier values without quotes.
+pub fn object_name_to_string_unquoted(name: &ObjectName) -> String {
+    name.0
+        .iter()
+        .map(ObjectNamePartExt::to_string_unquoted)
+        .collect::<Vec<_>>()
+        .join(".")
+}
+
+#[cfg(test)]
+mod tests {
+    use sqlparser::ast::{Ident, ObjectName, ObjectNamePart};
+
+    use super::object_name_to_string_unquoted;
+
+    #[test]
+    fn test_object_name_to_string_unquoted() {
+        let quoted = ObjectName(vec![ObjectNamePart::Identifier(Ident::with_quote(
+            '"',
+            "query.parallelism",
+        ))]);
+        let unquoted = ObjectName(vec![
+            ObjectNamePart::Identifier(Ident::new("query")),
+            ObjectNamePart::Identifier(Ident::new("parallelism")),
+        ]);
+
+        assert_eq!("query.parallelism", object_name_to_string_unquoted(&quoted));
+        assert_eq!(
+            object_name_to_string_unquoted(&unquoted),
+            object_name_to_string_unquoted(&quoted)
+        );
+    }
+}