How to manage copyright notices?

[kmpeters]

The EPICS License

Section 2 of the EPICS license implies that a list of primary copyright license holders of the motor module should be maintained at the top of the license file:

motor/LICENSES/EPICS.txt

Lines 12 to 14 in 7378022

	2. The copyright holders shown above and their third-party licensors
	hereby grant Licensee a royalty-free nonexclusive license, subject to
	the limitations stated herein and U.S. Government license rights.

The EPICS license doesn't appear to require the preservation of copyright notifications in any of the other source files.

The EPICS license requires derivative works to "carry prominent notices stating that you changed portions of the Software":

motor/LICENSES/EPICS.txt

Lines 33 to 35 in 7378022

	c. Modified copies and works based on the Software must carry
	prominent notices stating that you changed specified portions of
	the Software.

Recommendations for copyright notices in open-source software projects

This Linux Foundation blog post on copyright notices in open source software projects makes very good arguments for not trying to maintain a list of every copyright holder:

There are several reasons why LF project communities do not require or recommend trying to list every copyright holder for contributions to every file:

    * Copyright notices are not mandatory in order for the contributor to retain ownership of their copyright.
    * Copyright notices are rarely kept up to date as a file evolves, resulting in inaccurate statements.
    * Trying to keep notices up to date, or to correct notices that have become inaccurate, increases the burden on developers without tangible benefit.
    * Developers and maintainers often do not want to have to worry about e.g. whether a minor contribution (such as a typo fix) means that a new copyright notice should be added.
    * Adding many different copyright notices may increase the burden on downstream distributors, when their license compliance processes involve reproducing notices.
    * The specific individual or legal entity that owns the copyright might not be known to the contributor; it could be you, your employer, or some other entity.

Obstacles to determining who the current copyright holders are

• The motor module's git history only goes back to 2000-02-08, but the module is older than that.

• There is an originality requirement for copyright to apply. Fixing typos and improving code formatting are not sufficient for copyright ownershipo changes. Determining if changes are creative enough for copyright ownership of lines to change is a legal question, not a technical one.

• git blame only shows the person who last changed each line in a source file. There is not an easy way to show only "non-trivial" changes.

Takeaways

• Contributors of sufficiently creative/original changes (or their employers) own the copyright for the lines of code they add/change, whether or not an optional copyright notice is added to the source files.

• Adding copyright notices to the EPICS license file might be required.

Outstanding questions for lawyers

• If a contributor added a copyright statement to a source file and/or the EPICS license file and the non-copyright lines from the contributor are no longer present in the source files, can the copyright statement(s) be removed?

• Does Section 2 of the EPICS license require every copyright holder to add a copyright statmement to the top of the EPICS license?

• Is the git commit history of a fork of the motor module sufficient to comply with the Section 4c of the EPICS license?

[kmpeters]

This issue arose from #222 and #235