TraceMonkey and GNU GPL license

Question

I am trying to embed a Javascript engine into my application. But the license for Mozilla Javascript engine is GNU/GPL/MPL based and I don't have the time and energy to digest the cryptic legal document.

In short, does the license mean I need to publish my application's source code if I embed the engine into my own appli.? Something I think is quite impossible but as what i understand from the CopyLeft license, any work derived from modifying the source code means the derived work must be made open source as well.

Section 3.2 of MPL troubles me:

http://www.mozilla.org/MPL/MPL-1.1.html

3.2. Availability of Source Code. Any Modification which You create or to which You contribute must be made available in Source Code form under the terms of this License either on the same media as an Executable version or via an accepted Electronic Distribution Mechanism to anyone to whom you made an Executable version available; and if made available via Electronic Distribution Mechanism, must remain available for at least twelve (12) months after the date it initially became available, or at least six (6) months after a subsequent version of that particular Modification has been made available to such recipients. You are responsible for ensuring that the Source Code version remains available even if the Electronic Distribution Mechanism is maintained by a third party.

Answer 1

It's actually GPL 2/LGPL 2.1/MPL 1.1. This means you pick the license of your choice among these 3. Though the LGPL and MPL are different, neither of them require you to publish your application source code. IANAL. TINLA.

EDIT: Modification is defined as:

"Modifications"

means any addition to or deletion from the substance or structure of either the Original Code or any previous Modifications. When Covered Code is released as a series of files, a Modification is:

a. Any addition to or deletion from the contents of a file containing Original Code or previous Modifications.

b. Any new file that contains any part of the Original Code or previous Modifications.

As long as you do not modify the Tracemonkey files, and don't copy their code into your files, it doesn't count as a modification. Code you create in separate files is not covered.

Answer 2

TraceMonkey is GPL/LGPL/MPL. You can safely use LGPL license as long as you link dynamically with the library. Do consider google's V8 engine as it is faster and uses less restrictive license (BSD).