fix(sqlite): regression when decoding nulls (#3991)

Author: abonander

sqlx-sqlite/src/value.rs

@@ -278,10 +278,14 @@ impl ValueHandle {
         unsafe { Self::try_dup_of(self.value.as_ptr(), self.column_type.clone()) }
     }
 
-    fn type_info(&self) -> SqliteTypeInfo {
-        let value_type = SqliteTypeInfo(DataType::from_code(unsafe {
+    fn value_type_info(&self) -> SqliteTypeInfo {
+        SqliteTypeInfo(DataType::from_code(unsafe {
             sqlite3_value_type(self.value.as_ptr())
-        }));
+        }))
+    }
+
+    fn type_info(&self) -> SqliteTypeInfo {
+        let value_type = self.value_type_info();
 
         // Assume the actual value type is more accurate, if it's not NULL.
         match &self.column_type {
@@ -305,7 +309,7 @@ impl ValueHandle {
     }
 
     fn is_null(&self) -> bool {
-        self.type_info().is_null()
+        self.value_type_info().is_null()
     }
 }
 

tests/sqlite/sqlite.rs

@@ -1416,3 +1416,25 @@ enum SqliteTransactionState {
     Read,
     Write,
 }
+
+#[sqlx_macros::test]
+async fn issue_3982() -> anyhow::Result<()> {
+    let mut conn = new::<Sqlite>().await?;
+
+    let r = sqlx::raw_sql("insert into products(product_no) values(1)")
+        .execute(&mut conn)
+        .await?;
+    assert_eq!(r.rows_affected(), 1);
+
+    let (name,) = sqlx::query_as::<_, (Option<String>,)>(
+        r#"
+        select name from products where name IS NULL
+        "#,
+    )
+    .fetch_one(&mut conn)
+    .await?;
+
+    assert_eq!(name, None,);
+
+    Ok(())
+}

tests/sqlite/types.rs

@@ -34,6 +34,10 @@ test_type!(str<String>(Sqlite,
     "''" == ""
 ));
 
+test_type!(null_str<Option<String>>(Sqlite,
+    "NULL" == None::<String>
+));
+
 test_type!(bytes<Vec<u8>>(Sqlite,
     "X'DEADBEEF'"
         == vec![0xDE_u8, 0xAD, 0xBE, 0xEF],