PHP Version Switcher has no error checking at all.

The php-rebuild.sh script has no error checking for failures in "configure" or "make" steps. If `configure` fails, for some reason (like the infamous oniguruma/oniguruma5 dependency conflict), the script continues and does nothing to inform the user of the error, and proceeds to handle `php.ini` edits and everything. There should MANDATORILY be an error trap, even as simple as `|| die "Configure failed with error $?"` sprinkled around the script.

you've php build log where you can search and check the errors.

Sure, but seeing an error and then more entries in the log suggests that the error wasn't fatal at all, and that the script proceeded as intended. Not failing after a critical error is simply bad, there's no other way to say it.

for now your only solution is to view the log, in future we can add more checks but don't know when it will be implemented.