From: eregontp@... Date: 2017-12-20T17:35:33+00:00 Subject: [ruby-core:84377] [CommonRuby Feature#8257] Exception#cause to carry originating exception along with new one Issue #8257 has been updated by Eregon (Benoit Daloze). ko1 (Koichi Sasada) wrote: > What happen on exception from deep backtrace, occurred by other more > deeper exception? Show all long two backtraces? Yes, although we can omit the common part of the backtrace in the cause backtraces like in Java: http://www.codejava.net/java-core/exception/understanding-exception-stack-trace-in-java-with-code-examples peterfaiman (Peter Faiman) wrote: > Is there a reason not to do caused-by stack trace printing? Or has it just not been implemented by anyone yet? I believe it was just no implemented yet. @ko1 Who should we assign this to? ---------------------------------------- Feature #8257: Exception#cause to carry originating exception along with new one https://bugs.ruby-lang.org/issues/8257#change-68566 * Author: headius (Charles Nutter) * Status: Closed * Priority: Normal * Assignee: matz (Yukihiro Matsumoto) * Target version: Ruby 2.1.0 ---------------------------------------- Often when a lower-level API raises an exception, we would like to re-raise a different exception specific to our API or library. Currently in Ruby, only our new exception is ever seen by users; the original exception is lost forever, unless the user decides to dig around our library and log it. We need a way to have an exception carry a "cause" along with it. Java has getCause/setCause and standard constructors that take a cause exception. Printing out an exception's backtrace then reports both that exception and any "cause" exception. Rubinius has added a similar feature: https://gist.github.com/dbussink/b2e01e51d0c50b27004f The changes required for this feature are pretty benign: * Exception#cause and #cause= accessors. * A new set of Kernel#raise overloads that accept (as a trailing argument, probably) the "cause" exception. * Modifications to backtrace-printing logic to also display backtrace information from the "cause" exception (and in turn, from any nested "cause" exceptions). There's some discussion here about alternatives to #cause, none of which are quite as elegant as having it built in: http://www.skorks.com/2013/04/ruby-why-u-no-have-nested-exceptions/ -- https://bugs.ruby-lang.org/ Unsubscribe: