fix(mysql): restore bind buffer length for newer mariadb versions

Author: simonz

diesel/src/mysql/connection/stmt/mod.rs

@@ -117,7 +117,14 @@ impl Statement {
     /// you must call this function again before calling `mysql_stmt_fetch`.
     pub unsafe fn bind_result(&self, binds: *mut ffi::MYSQL_BIND) -> QueryResult<()> {
         unsafe {
+            let prev_length = *(*binds).length;
             ffi::mysql_stmt_bind_result(self.stmt.as_ptr(), binds);
+
+            // HACK: Newer libmariadb versions initialise length to 0 for fixed-size
+            // types. Restore length to previous value if this is the case.
+            if *(*binds).length == 0 {
+                *(*binds).length = prev_length;
+            }
         }
         self.did_an_error_occur()
     }