Two new reports are warning the governments of New Zealand and Québec of the potential legal dangers of using and modifying open-source software, with one advising that some open-source licences are "highly infectious".

The reports underscore the growing interest governments are taking in making use of open-source software and licences.

The New Zealand report, prepared for the State Services Commission (SSC) by law firm Chapmann Tripp, takes the more alarmist approach of the two, warning that some open-source licences pose the risk of infecting other software, and potentially forcing government agencies to disclose source code.

Some open-source licences contain what the Free Software Foundation calls "copyleft", the requirement that if a program is copied, modified or integrated into another program, the resulting derivative work must be covered by the same licence as the original. The GNU General Public License, the most popular open-source licence, which covers the Linux kernel, is a prime example of a licence containing copyleft.

In using the term "infectious" to describe copyleft, Chapmann Tripp said it is taking its lead from a paper called "'Infectious' open source software: spreading incentives or promoting resistance?" by law professor Greg Vetter.

In that paper, Vetter took a dim view of copyleft and similar requirements. "On balance, such terms may produce incentives detrimental to interoperability and coexistence between open and proprietary code," he wrote. Vetter recommended greater precision in defining their "infectious" terms.

Chapmann Tripp also identified imprecision and lack of information as the source of dangers around copyleft. The paper says the GPL "is not entirely clear on the degree or methods of separation necessary to prevent the GPL from infecting software".

Those merely using an "infectious" program shouldn't be in any danger of affecting other software, but, the firm said, "it can be unclear what constitutes 'mere use' without infection."

In most cases, "the infectious effects of open source licences can be 'quarantined' by keeping open source components sufficiently separate from the rest of the software," the firm said. In risky situations involving highly confidential software, government agencies may want to get specific legal advice, Chapmann Tripp said.

Software patents pose a particular risk to users of open-source software, because the software usually comes without any form of legal indemnification, putting the burden on users, the report said.

Ultimately, the firm's advice is to be sure to understand the terms of the licences involved. The firm notes that several open-source licences, including the GPL and the Lesser GPL, have been approved for the government's use.

The Québec report, called "The Legal Issues Surrounding Free and Open Source Software: Challenges and Solutions for the Government of Québec", prepared by Pierre-Paul Lemyre and Richard Willemant, is less alarmist in tone. The 77-page paper finds that open-source licences generally do not have any conflict with Québec law, though procedures should be put into place for using the licences.

"The Government of Québec can easily adopt free and open source software, at least as far as the law is concerned, provided some measures are implemented," Lemyre and Willemant wrote.

However, the authors advised strongly against any sort of legislation that would compel the government to give priority to open-source software, warning that any such legislation could conflict with free trade agreements such as GATT and NAFTA.