From 7197858e21ebe4396a125da0ac3818c344c7c14e Mon Sep 17 00:00:00 2001
From: Ning Sun <sunning@greptime.com>
Date: Sun, 15 Feb 2026 15:29:25 +0800
Subject: [PATCH] fix: add support for moving nested cast

---
 datafusion-pg-catalog/src/sql/rules.rs | 22 ++++++++++++++++++++++
 datafusion-postgres/tests/pgadbc.rs    | 24 ++++++++++++++++++++++++
 2 files changed, 46 insertions(+)
 create mode 100644 datafusion-postgres/tests/pgadbc.rs

diff --git a/datafusion-pg-catalog/src/sql/rules.rs b/datafusion-pg-catalog/src/sql/rules.rs
index 91c6553..6853700 100644
--- a/datafusion-pg-catalog/src/sql/rules.rs
+++ b/datafusion-pg-catalog/src/sql/rules.rs
@@ -361,6 +361,7 @@ impl VisitorMut for RemoveUnsupportedTypesVisitor<'_> {
                     .unsupported_types
                     .contains(data_type.to_string().to_lowercase().as_str())
                 {
+                    self.remove_nested_unsupported_casts(value);
                     *expr = *value.clone();
                 }
             }
@@ -372,6 +373,25 @@ impl VisitorMut for RemoveUnsupportedTypesVisitor<'_> {
     }
 }
 
+impl RemoveUnsupportedTypesVisitor<'_> {
+    fn remove_nested_unsupported_casts(&mut self, expr: &mut Expr) {
+        if let Expr::Cast {
+            data_type,
+            expr: value,
+            ..
+        } = expr
+        {
+            if self
+                .unsupported_types
+                .contains(data_type.to_string().to_lowercase().as_str())
+            {
+                self.remove_nested_unsupported_casts(value);
+                *expr = *value.clone();
+            }
+        }
+    }
+}
+
 impl SqlStatementRewriteRule for RemoveUnsupportedTypes {
     fn rewrite(&self, mut statement: Statement) -> Statement {
         let mut visitor = RemoveUnsupportedTypesVisitor {
@@ -995,6 +1015,8 @@ mod tests {
     WHERE c.oid = '16386'",
             "SELECT c.relchecks, c.relkind, c.relhasindex, c.relhasrules, c.relhastriggers, c.relrowsecurity, c.relforcerowsecurity, false AS relhasoids, c.relispartition, '', c.reltablespace, CASE WHEN c.reloftype = 0 THEN '' ELSE c.reloftype::TEXT END, c.relpersistence, c.relreplident, am.amname FROM pg_catalog.pg_class AS c LEFT JOIN pg_catalog.pg_class AS tc ON (c.reltoastrelid = tc.oid) LEFT JOIN pg_catalog.pg_am AS am ON (c.relam = am.oid) WHERE c.oid = '16386'"
         );
+
+        assert_rewrite!(&rules, "SELECT $1::regclass::oid", "SELECT $1");
     }
 
     #[test]
diff --git a/datafusion-postgres/tests/pgadbc.rs b/datafusion-postgres/tests/pgadbc.rs
new file mode 100644
index 0000000..24db14a
--- /dev/null
+++ b/datafusion-postgres/tests/pgadbc.rs
@@ -0,0 +1,24 @@
+use pgwire::api::query::SimpleQueryHandler;
+
+use datafusion_postgres::testing::*;
+
+const PGADBC_QUERIES: &[&str] = &[
+    "SELECT attname, atttypid FROM pg_catalog.pg_class AS cls INNER JOIN pg_catalog.pg_attribute AS attr ON cls.oid = attr.attrelid INNER JOIN pg_catalog.pg_type AS typ ON attr.atttypid = typ.oid WHERE attr.attnum >= 0 AND cls.oid = 1602::regclass::oid ORDER BY attr.attnum",
+
+
+];
+
+#[tokio::test]
+pub async fn test_pgadbc_metadata_sql() {
+    env_logger::init();
+    let service = setup_handlers();
+    let mut client = MockClient::new();
+
+    for query in PGADBC_QUERIES {
+        SimpleQueryHandler::do_query(&service, &mut client, query)
+            .await
+            .unwrap_or_else(|e| {
+                panic!("failed to run sql:\n--------------\n {query}\n--------------\n{e}")
+            });
+    }
+}