Follow GPL and other open-source licenses: disclose source when required or choose different licensing
In China, copyright damages may follow the owner's loss or the infringer's profits, and intentional serious infringement can bring 1–5 times damages. A company recruited a competitor's former employee and made substantially similar software, then argued that the original used GPLv2 and should have been open source. The Supreme Court held that the original developer's own licensing compliance was separate from copyright ownership and ordered infringement to stop plus RMB 500,000 compensation.
What it takes
Free. Read a library's license before using it. GPL-family licenses can require disclosure of corresponding product source, conflicting with a closed-source business plan; if that conflicts, choose another option. Abandoning a familiar library is the difficult part.
What you may gain
Copyright damages use actual loss or infringing profits; if neither is ascertainable, normal licensing fees inform the amount. Intentional, serious infringement may bring damages at 1–5 times the applicable base. Harm to public interests can also bring confiscation and fines. In case (2021) Supreme Court IP Civil Appeal No. 51, the defendant hired the plaintiff's former employees and developed substantially similar gateway software. Its GPLv2 argument failed: the Supreme Court treated the developer's own GPLv2 compliance and ownership of copyright as independent issues and ordered cessation plus RMB 500,000. Chinese law applies.
Context & considerations
Someone else's GPL use is not a defense for copying their work. Effective Chinese judgments on GPL authors suing commercial users who withhold source also exist, but no original judgment was found on the Supreme Court website, so none is cited here. Grade B reflects reliance on general contract and copyright rules rather than a dedicated statutory provision for open-source compliance.
Research & references
NPC Standing Committee (2020). Copyright Law, 2020 revision, Articles 53 and 54. http://www.npc.gov.cn/npc/c2/c30834/202011/t20201119_308796.html; Supreme People's Court Intellectual Property Court (2022). Copyright Infringement Involving Open-Source Software, (2021) IP Civil Appeal No. 51. https://ipc.court.gov.cn/zh-cn/news/view-3042.html