725741 - proper serialization of JSScript::filename for scripts using //@line

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[Igor Bukanov]

Our parser supports optional //@line lineno "<filename>" instructions to control from the script line numbers and file names that will be reported in errors originated in the script. This instruction can appear multiple times so potentially JSScipt instances created for functions nested in the script may have different JSScript::filename. 

However, our XDR and js_CloneScript implementation assumes that all nested function in the top-level script shares the same filename leading to incorrect decoding of serialized scripts.

Currently this issue does not affect Firefox as the support fro @line is not enabled at runtime.