updating from previous version (app-arch/snappy-1.1.3-r1) to 1.1.7 causes chromium to be rebuild whenever emerge update is called. However, rebuilding chromium has no effect and the rebuild is triggered again during the next world update. My current chromium version is 63.0.2239.108(stable).
I suspect it is connected to the SLOT line in the snappy ebuild which is different from the one in 1.1.3-r1:
Downgrading to previous version of snappy resolves the issue.
Sounds like a Portage problem. Subslot change should only trigger one rebuild.
Also, please attach the last build logs for chromium and output of 'emerge ... @world' that triggers the issue for you. Also 'emerge --info'.
I'm not able to reproduce the issue with a system having app-arch/snappy-1.1.7 and www-client/chromium-63.0.3239.108. I've tested with sys-apps/portage-2.3.13-r1 and sys-apps/portage-2.3.19-r1.
Things to check:
If chromium was built with snappy-1.1.7 then you should find "app-arch/snappy:0/1=" in these files:
You should find "0/1" in this file: