Currently, Zeek disables any static type checking for var_arg bifs.
However, the generated preamble for var_args bifs assume that
typed positional arguments are correctly typed and blindly calls
the type converters on them. This easily triggers abort()s at runtime
currently when a script mistakenly uses the wrong types for var_arg
bifs. For example, calling publish_rr() with a port instead of a string
causes a hard-abort with Zeek 5.0.8.
$ zeek -e 'Cluster::publish_rr(Cluster::Pool(), 80/tcp)'
fatal error in <no location>: Val::CONVERTER (port/string) (80/tcp)
Aborted (core dumped)
Extend bifcl so that for var_arg functions and the types that bifcl understands,
we render a runtime type check and explicit early return to avoid the abort().
For any/other types, the implementer of the bif continuous to be responsible
for type checking.
This isn't solving the var_args situation generally, but avoids some
ad-hoc fixes trickling in current bif implementations.
Some references:
https://github.com/zeek/zeek/issues/1523https://github.com/zeek/zeek/issues/2425https://github.com/zeek/zeek/issues/2935https://github.com/zeek/zeek/pull/2950
This avoids potential problems with libc++ 8+ on case-insensitive file
systems due to inclusion of a new header called <version> which will end
up conflicting with the VERSION file if the search path includes the
project root.
