Problem: Merging UpstreamPRs may not be a good idea

[weex]

Some concerns have been raised here, here and here about merging PRs from upstream. They are summarized here:

• First, that such PRs might be work-in-progress and that by merging code before upstream maintainers, we would be taking on additional risk on a patch which may still receive comments and changes.
• Second, if more changes are made and then the code is then merged upstream, we may have conflicts to resolve which might make merging not worth the extra maintenance.
• Third, the author of the patch may be surprised that their code is used on a fork.

Are there other concerns that should be raised about this practice?

[weex]

I think this can still be a valuable practice to bootstrap and doesn't seem to have caused any major problems, but at this point we have plenty of issues coming in from our community to keep us busy.