Sorry - I missed this. :P
Have you heard of David Wheeler? He's a well respected contributor in open source. He wrote an article frequently referred, entitled Make Your Open Source Software GPL-Compatible. Or Else.
One of the reasons I enjoy Wheeler's work is that he is precise and articulate with assertions, he uses facts - links to licenses, counts, statistics, quotes, etc. Verification is then possible and over time he has been found to be a credible expert for project teams to use for guidance. If you read that article, you will find many reasons it is important for an open source project to use and enforce an open source license.
Your valid concern for a project attracting developers is Wheeler's primary focus
for this particular study, and he uses the balance of his report to offer evidence validating this assertion:
"Why a GPL-compatible license? Because if your OSS/FS project isn’t GPL-compatible, there’s a significant risk that you’ll fail to receive enough support from other developers to sustain your project."
In particular, I recommend the section entitled 3. Other projects show GPL compatibility important
, where Wheeler states: "several large, high-profile OSS/FS projects have undergone painful changes to make themselves GPL-compatible" and then he lists projects including Python, vim, Mozilla, Zope, Apache, Wine, Alfresco.
This is also a good post by Rob Schley, Joomla! core team member where he talks about the FOSS ecosystem and sharing source code solutions between projects
. Those possibilities are impossible once you start to compromise the project's license. The option to share code with another GPL project is gone. That is a huge loss.
Joomla! is in good company as those are hugely mega-successful open source projects. I believe Joomla!'s continued success will be linked to this license clarification, which, in turn, will further
strengthen third party extensions. It is worth noting that the vast
majority of Joomla! extensions today are already GPL, or GPL-compatible.
Regarding Joomla!'s plans for compliance, please see the project team's announcement, Open Source Does Matter ...
. Here's part of their statement:
Here's the plan: first, we clean our own house and bring the Joomla! sites into compliance. Next, we ask people in the community to voluntarily comply with the license. At the same time, we try to help people understand what it takes to comply and how they can do it easily. We believe we're going to get a lot of compliance that way.
So far, that's the entire plan. No lawsuits, no pogroms, no martyrs. More to the point, no shouting, no demonisation, and no drawing lines between "us" and "them". It's a big community with many kinds of developers, and we want solutions that will work for everybody.
I believe the Joomla! community will get behind this project and support it well into the future.
Returning to your original question as to why there is no SMF bridge. It is important to understand that this was an SMF decision, and the best way to understand "why" they reached this conclusion is to read their announcement entitled SMF Bridge for Joomla! Discontinued
where they published an email exchange they had with Brett Smith, licensing Compliance Engineer for the FSF. The discussion was very broad. Joomla! was never mentioned and Joomla! team members were not involved.
The essence of the question SMF posed to the FSF is as follows (quoting from that text):
First Script (GPL) "Glue" Script Second Script
If the glue does have to be GPL (or LGPL), could the second script be then legally licensed under a non-compatible license?
The answer provided by Smith was "No."
There are many licenses that are GPL-compatiable licenses
. The SMF license is not compatiable because of restrictions the SMF license places on end users. For example:
Agreement. 1. d. Any Distribution of this Package, whether as a Modified Package or not, requires express written consent from Simple Machines LLC.
That restriction alone fails the first test of an the Open Source Definition
1. Free Redistribution
The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale.
All of this seems is
frustrating to us as end users. Personally, I have urged SMF to adopt one of the many GPL-compatiable licenses
available. If they were to do that, no GPL project team would have to grant them authority to violate the terms of the GPL. (And thus risk ability to share code and get the benefits Wheeler mentions.) There are many GPL projects that have SMF bridges - it would benefit each of them if SMF's license were compatiable with the GPL because of the very question SMF and the FSF discussed.
, I do not get to select SMF's license, nor do I have any influence over Joomla!'s license. The bottom line is SMF is free to license their work as they choose. They are free to build bridges or not to build bridges. Joomla! developers are also free to protect their work as they believe is in the best interest of their project. This is not clear-cut or easy and it is not without challenges to those of us who use this fabulous software.
In this particular
case, it is more heartbreaking given the long term friendship and value provided by the combined software.
There are ways to bridge the software environments without breaking the terms of either license. Those methods were discussed in the FSF and SMF exchange. However, it is more challenging to connect proprietary code to an open source environment than it is to connect code that shares the same license terms. Maybe someone will use these methods to innovate a solution between the two packages.
There is a bridge being beta tested
for Joomla! and phpBB3, all three GPL software solutions. SMF continues to offer a number of bridges for other CMS environments we can freely choose from. Further, one can use SMF in a stand-alone environment without integrating to a CMS, just like this forum does. We are not without our choices.