It is not clear to me how this relates to your question about workspaces:
Now I am allowing users to overwrite user, host, port, stream,
revision.
since only one of those is a property of a workspace. I'm going to disregard that statement for now but if it was significant I'd encourage you to post a follow-up clarifying what you mean by "overwriting" each of these properties.
To your question:
From the docs it is not clear to me when I have to execute which
commands to get the client workspace files in sync with an edited
client workspace spec.
If the client View is updated, all you need to do is:
p4 sync
If the client Root is updated, or any of the other options that globally affect how files are written to the workspace, such as allwrite or modtime, you will need to re-sync the entire client. Ideally this is done by doing:
p4 sync #none
prior to changing the workspace in one of these ways. The other option would be to do something like the following sequence:
p4 sync #none
p4 sync
p4 clean
to make sure that everything is rewritten, and that any stragglers (e.g. anything that the "sync #none" couldn't locate because the Root had changed but that are still mapped in the client view) are removed from the workspace.
I tried executing e.g. p4 sync -s in hope that it would fail should
local data be deleted but it seems that I misunderstood the option?
Deleting local data is a separate issue from editing the client spec, but for that the command you want is p4 clean rather than p4 sync -- you use sync to tell the server you want it to send you new revisions, you use clean to bring your workspace back in line with what the server already sent you.
The recommended/supported workflow is to always use p4 commands to manipulate the read-only files in your workspace -- so if you want to delete a local file, use either p4 sync FILE#none (to remove it from your workspace but not affect the depot) or p4 delete FILE (to open it for delete so that it will be deleted for everyone when you submit).
p4 sync. You shouldn't need to pass the-fnor-sflags. Can you provide a more exact example of why a simplep4 syncisn't working for you? - Bryan Pendleton