netty5/common
Carl Mastrangelo d3ca087f6b Propagate all exceptions when loading native code
Motivation:
There are 2 motivations, the first depends on the second:

Loading Netty Epoll statically stopped working in 4.1.16, due to
`Native` always loading the arch specific shared object.  In a
static binary, there is no arch specific SO.

Second, there are a ton of exceptions that can happen when loading
a native library.  When loading native code, Netty tries a bunch of
different paths but a failure in any given may not be fatal.

Additionally: turning on debug logging is not always feasible so
exceptions get silently swallowed.

Modifications:

* Change Epoll and Kqueue to try the static load second
* Modify NativeLibraryLoader to record all the locations where
  exceptions occur.
* Attempt to use `addSuppressed` from Java 7 if available.

Alternatives Considered:

An alternative would be to record log messages at each failure.  If
all load attempts fail, the log messages are printed as warning,
else as debug. The problem with this is there is no `LogRecord` to
create like in java.util.logging.  Buffering the args to
logger.log() at the end of the method loses the call site, and
changes the order of events to be confusing.

Another alternative is to teach NativeLibraryLoader about loading
the SO first, and then the static version.  This would consolidate
the code fore Epoll, Kqueue, and TCNative.   I think this is the
long term better option, but this PR is changing a lot already.
Someone else can take a crack at it later

Results:
Epoll Still Loads and easier debugging.
2017-10-04 08:45:27 +02:00
..
src Propagate all exceptions when loading native code 2017-10-04 08:45:27 +02:00
pom.xml [maven-release-plugin] prepare for next development iteration 2017-09-25 06:12:32 +02:00