9. Apache v2.0, MIT, BSD
No copyleft
Could be integrated in closed source software
You must mention authors
Trigger : distribution
10. GPL v3
Strong copyleft
Source code has to be available
‘contaminates’ the whole work
You must mention authors
Trigger : distribution
11. GPL v2
Strong copyleft
You must mention authors
Source code has to be available
‘contaminates’ the whole work
Incompatible with a lot of common licenses
Trigger : distribution
12. AGPL v3
“Affero GPL”
Super strong copyleft
Source code has to be available
‘contaminates’ the whole work
You must mention authors
Trigger : distribution & interactions through a network
13. LGPL v3
Weak copyleft
Could be integrated in closed source software, provided you
make possible to link with another version of the library
Intended for libraries
You must mention authors
Trigger : distribution
14. Creative Commons licenses
Not adapted to software!
Adapted to documentation
Attribution
Attribution
No derivatives
Attribution
No commercial use
Share alike
Attribution
Share alike
Attribution
No commercial use
Attribution
No commercial use
No derivatives
16. Copyleft “contamination”
• Compiled in 1 executable à contamination
• Calling another executable and sharing data through
command line or file à no contamination
• Run a software on a ‘copyleft’ operating system à
no contamination from OS
• Interact with a webservice through standardized
protocol (query online database with SQL) à no
contamination
20. PhD Thesis - SimCity
Effect of urban development on traffic jam
SimCity
2D engine for maps
Export to xls
Color picker (palette)
21. PhD Thesis - SimCity
SimCity
2D engine for maps
Export to xls
Color picker (palette)
May I sell
Licenses ?
Effect of urban development on traffic jam
22. PhD Thesis - SimCity
SimCity
2D engine for maps
Export to xls
Color picker (palette)
May I sell
Licenses ?
Effect of urban development on traffic jam
23. PhD Thesis - SimCity
SimCity
2D engine for maps
Export to xls
Color picker (palette)
May I Open
Source ?
Effect of urban development on traffic jam
24. PhD Thesis - SimCity
SimCity
2D engine for maps
Export to xls
Color picker (palette)
May I Open
Source ?
Effect of urban development on traffic jam
25. Some known compatibilty problems
• BSD-4 à GPL
• Apache v1, v1.1 à GPL
• GPLv2 à GPLv3
• GPLv3 à GPLv2
• MPLv1.1 à GPL
! GPL compatible licences
https://www.gnu.org/licenses/license-list
26. Dual licensing
Purpose :
▸ Prevent compatibility issues (ex : using GPL v2+)
▸ Run a dual licensing business model
Needs agreement of all rights owners
▸ 1 owner, or…
▸ All owners agree, or…
▸ Unify rights via CLA (Contributor License Agreement)
31. How to solve incompatibility ?
• Don’t bother (short code)
• Rewrite
• Replace with another library
• Ask authors for a different license
• Split your software (if at all possible)
33. What are the risks ?
1. OS license incompatibility in an open source project
è Reputation
è Trouble in OS community
è (Lawsuit)
è Stop distribution
34. What are the risks ?
2. Copyleft code in commercial code
è Development costs to clear the situation
è Lawsuit
è reputation
è open your code !!
è pay damages
è Dev companies : your customer could be sued
36. For developpers…
• Choose a distribution strategy from the start
(commercial, permissive, copyleft…)
• and choose dependencies with a compatible license
• Ask your employer
• Before contributing to an open source project
• Before integrating OS in the company software !
37. For developpers…
• Document your code with legal stuff
• Copyright and license header in each source file
• LICENSE and AUTHOR file
• Use a Version Control System (Git, SVN…)
• Test in branches
• Track who did what
• Use Fossology
39. For companies : Open Source Policy
• OS licenses allowed, and not allowed
• Other criteria : maintenance, quality, security…
• Clear and rapid validation procedure
• Contributing to an open source project
• Inventory of dependencies
• Use tracking tools