From d3f84f2d9e1e7e4113eb57a402afab9d0cd9ea77 Mon Sep 17 00:00:00 2001
From: Jiseok CHOI <jiseok.dev@gmail.com>
Date: Sat, 15 Aug 2026 14:54:58 +0900
Subject: [PATCH] sqlite3: validate narg before creating functions/aggregates

CPython 3.14 added check_num_params() which raises ProgrammingError when
narg/n_arg/num_params is out of range (-1..=SQLITE_LIMIT_FUNCTION_ARG).
RustPython passed invalid values directly to SQLite, resulting in an
OperationalError instead.

Add check_num_params() helper and call it in create_function(),
create_aggregate(), and create_window_function().

Assisted-by: GitHub Copilot:claude-sonnet-4-6
---
 Lib/test/test_sqlite3/test_userfunctions.py |  3 ---
 crates/stdlib/src/_sqlite3.rs               | 19 +++++++++++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_sqlite3/test_userfunctions.py b/Lib/test/test_sqlite3/test_userfunctions.py
index e7cecb85213..6da92d77616 100644
--- a/Lib/test/test_sqlite3/test_userfunctions.py
+++ b/Lib/test/test_sqlite3/test_userfunctions.py
@@ -170,7 +170,6 @@ def setUp(self):
     def tearDown(self):
         self.con.close()
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; error message differs for invalid num args
     def test_func_error_on_create(self):
         with self.assertRaisesRegex(sqlite.ProgrammingError, "not -100"):
             self.con.create_function("bla", -100, lambda x: 2*x)
@@ -514,7 +513,6 @@ def test_win_sum_int(self):
         self.cur.execute(self.query % "sumint")
         self.assertEqual(self.cur.fetchall(), self.expected)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; error message differs for invalid num args
     def test_win_error_on_create(self):
         with self.assertRaisesRegex(sqlite.ProgrammingError, "not -100"):
             self.con.create_window_function("shouldfail", -100, WindowSumInt)
@@ -649,7 +647,6 @@ def setUp(self):
     def tearDown(self):
         self.con.close()
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; error message differs for invalid num args
     def test_aggr_error_on_create(self):
         with self.assertRaisesRegex(sqlite.ProgrammingError, "not -100"):
             self.con.create_function("bla", -100, AggrSum)
diff --git a/crates/stdlib/src/_sqlite3.rs b/crates/stdlib/src/_sqlite3.rs
index 5348cc1f5ec..5576b84629f 100644
--- a/crates/stdlib/src/_sqlite3.rs
+++ b/crates/stdlib/src/_sqlite3.rs
@@ -1279,6 +1279,7 @@ mod _sqlite3 {
                 SQLITE_UTF8
             };
             let db = self.db_lock(vm)?;
+            check_num_params(&db, args.narg, "narg", vm)?;
             let Some(data) = CallbackData::new(args.func, vm) else {
                 return db.create_function(
                     name.as_ptr(),
@@ -1310,6 +1311,7 @@ mod _sqlite3 {
         fn create_aggregate(&self, args: CreateAggregateArgs, vm: &VirtualMachine) -> PyResult<()> {
             let name = args.name.to_cstring(vm)?;
             let db = self.db_lock(vm)?;
+            check_num_params(&db, args.narg, "n_arg", vm)?;
             let Some(data) = CallbackData::new(args.aggregate_class, vm) else {
                 return db.create_function(
                     name.as_ptr(),
@@ -1392,6 +1394,7 @@ mod _sqlite3 {
         ) -> PyResult<()> {
             let name = name.to_cstring(vm)?;
             let db = self.db_lock(vm)?;
+            check_num_params(&db, narg, "num_params", vm)?;
             let Some(data) = CallbackData::new(aggregate_class, vm) else {
                 unsafe {
                     sqlite3_create_window_function(
@@ -3475,6 +3478,22 @@ mod _sqlite3 {
         Ok(obj)
     }
 
+    fn check_num_params(
+        db: &Sqlite,
+        n: c_int,
+        param_name: &str,
+        vm: &VirtualMachine,
+    ) -> PyResult<()> {
+        let limit = unsafe { sqlite3_limit(db.db, SQLITE_LIMIT_FUNCTION_ARG, -1) };
+        if n < -1 || n > limit {
+            return Err(new_programming_error(
+                vm,
+                format!("'{param_name}' must be between -1 and {limit}, not {n}"),
+            ));
+        }
+        Ok(())
+    }
+
     fn ptr_to_str<'a>(p: *const libc::c_char, vm: &VirtualMachine) -> PyResult<&'a str> {
         if p.is_null() {
             return Err(vm.new_memory_error("string pointer is null"));