[incubation] Contributions via GitHub, how to handle squash commits

[Jens von Pilgrim <developer@xxxxxxxxx>]

Dear All,

We host our project at GitHub particularly for simplifying contributions 
of non-committers.

There is not much documentation in the wiki about how to manage that:
"If the project repository is hosted on GitHub, you can issue a standard 
GitHub pull request. Ensure that you have a ECA and that the commit 
record is properly "Signed-off-by" before you issue the request."
https://wiki.eclipse.org/Development_Resources/Contributing_via_Git

Two questions regarding the "commit record":

1) What happens if a contributor has forgotten to sign-off? Is it 
possible to "sign-off" the pull-request?

2) We use "Squash and Merge" commits in order to reduce the size of the 
commit history and to simplify the identification of problematic commits 
(since a commit then usually correlates with a task and a specific fix 
or new feature). In that case, the initial "commit record" of the 
contributor is gone, and the commit has to be performed by a committer.

I think that I already have answers to these questions:

1) At least one commit needs to be signed of by the contributor, 
assuming all commits were done by the same contributor.

2) GitHub's "Squash and Merge" creates a new commit, but preserves the 
information about the original commits in the comment. This information 
is used by the IP tooling to gather information about the contributor, 
even though the "squash commit" is done by a committer.

Is this correct?

Best regards,
Jens