> If someone fixes or adds something valuable to GPL source code and wants to charge for it, then why not just charge for the patch or the additional code?
You can legally do this, but it will not be easy. You cannot distribute a binary in this way, if you do your patch becomes GPL so the first person who buys your patch can legally give it to everyone else. That means you have to sell the source code to your patch and your customers have to build the binary themselves. You need to ensure that your customers understand that they cannot distribute any binaries they make. (they probably can distribute it within their company but they need to have some process to ensure that their employees know they cannot distribute this)
If anyone is thinking about this, make sure all sales include your lawyer: you will need to ensure that your customer understands all the subtleties otherwise the courts might decide your patch is GPL.
To be clear, the silly question I posed was not directed at avoiding copyright violations. What I ask is whether anyone is ever curious about the value of the derivative work versus the original work.
For example, the original work might be very valuable, a significant work. It could be the collective work of many authors. But it has been made available for free. The derivative work, maybe patches or some additional source code by a single author, is also valuable but on its own much less so.
Then the large original work is packaged together with the patches and additonal source code as a "derivative work". It is commercially licensed to an end user who sees the value as a whole, most of it coming from the original work, which of course was available for free.
Depending on whether attribution is given, the user may have no idea that the core of the product was open source and available for free.
More importantly, there appears to be no assessment of the relative "value" of the free portion versus the closed-source commercial portion of the product.
I'm not entirely sure that's correct. If you try to sell something that relies on GPL software, it's considered a derivative work even if you don't distribute the GPL software with yours.
It is a derivative work, but selling derivatives of GPL-ed software is entirely legal and not forbidden by the GPL. Distributing binaries (regardless if for free or not) of GPL-derived software without distributing the source from which the binaries were derived (or without offering a reasonable way of getting the source on demand) is forbidden by the GPL.
Moreover, the source of the derivative work must be offered under the GPL.
(Edited to add the last statement above, for clarity.)
This is correct - you not only must include the source code for your binary, you also must include it under the same terms as the original source code.
So if someone just happens to distribute the source code for Hancom Office before this is resolved in the courts, would he or she be in the free and clear?
A license can't affect the copyright of any other code. So Hancom is just in violation of the GPL and has lost its right to use Ghostscript; it's not automatically GPL'd.
This is correct. Without a license, Hancom is liable for copyright infringement of the Artifex code if it continues distributing its product. It will be forced to either buy a license or reform its product to use an alternative, but it won't be forced to release its source code.
Probably not. It's unlikely either party will want this to go to trial so it'll probably end in a settlement where the company buys a license on top of damages.
You can legally do this, but it will not be easy. You cannot distribute a binary in this way, if you do your patch becomes GPL so the first person who buys your patch can legally give it to everyone else. That means you have to sell the source code to your patch and your customers have to build the binary themselves. You need to ensure that your customers understand that they cannot distribute any binaries they make. (they probably can distribute it within their company but they need to have some process to ensure that their employees know they cannot distribute this)
If anyone is thinking about this, make sure all sales include your lawyer: you will need to ensure that your customer understands all the subtleties otherwise the courts might decide your patch is GPL.