tldr: It's safe but mildly annoying. Please feel free to send a pull-request to update these files.
Longer: DAO files are auto-generated when
civibuild calls the script
xml/GenCode.php with the data in
xml/schema. However, running
GenCode is traditionally pretty slow -- even on a fast workstation, it can add 30 seconds to the build-time.
Starting somewhere in 4.7.x, we did an optimization: if the checksum looks right, then
GenCode keeps the DAO. (Hooray, faster!) If the checksum looks wrong, then it regenerates the DAO.
In a typical scenario, you might edit a file in
xml/schema, then run
GenCode, then observe several changes to your local DAO. The
GenCodeChecksum would be one of several changes. You'd commit those changes and send them in with the PR.
Right now, I see something like what you describe -- the only difference between the upstream DAO and the local DAO is the checksum. This can happen occasionally (eg if there were contemporaneous PRs manipulating schema and the precise order-of-operations was unfavorable). The consequences are:
GenCode spends an extra second regenerating 1-3 files.
git diff shows something unexpected on 1-3 files.
That's mildly annoying - but you still wind up with the right code, so it's safe.
You can fix it by submitting a PR to update the DAO's with the latest