From: naruse@...
Date: 2019-08-20T06:45:41+00:00
Subject: [ruby-core:94443] [Ruby master Bug#9115] Logger traps all	exceptions; breaks Timeout

Issue #9115 has been updated by naruse (Yui NARUSE).


See the code again before discuss.

```ruby
    def write(message)
      begin
        synchronize do
          if @shift_age and @dev.respond_to?(:stat)
            begin
              check_shift_log
            rescue
              warn("log shifting failed. #{$!}")
            end
          end
          begin
            @dev.write(message)
          rescue
            warn("log writing failed. #{$!}")
          end
        end
      rescue Exception => ignored
        warn("log writing failed. #{ignored}")
      end
    end
```
https://github.com/ruby/ruby/blob/5a384e2c08704dc7af9d8d3bdfc475eb8c0723aa/lib/logger/log_device.rb#L29-L48

With the code, the intention of `rescue Exception` is clear. It wants to rescue exceptions which is raised by `synchronize`.

And note that `synchronize` is Monitor's and it only raises ThreadError.
https://github.com/ruby/ruby/blob/master/lib/monitor.rb
I don't understand why it loosely rescues all exceptions.

----------------------------------------
Bug #9115: Logger traps all exceptions; breaks Timeout
https://bugs.ruby-lang.org/issues/9115#change-80869

* Author: cphoenix (Chris Phoenix)
* Status: Assigned
* Priority: Normal
* Assignee: sonots (Naotoshi Seo)
* Target version: 
* ruby -v: ruby 2.0.0p247 (2013-06-27) [i386-mingw32]
* Backport: 
----------------------------------------
Line 577-579 of logger.rb

      rescue Exception => ignored
        warn("log writing failed. #{ignored}")
      end

Thus, when the system times out in the middle of writing a log message, it warns "log writing failed. execution expired" and just keeps right on running.

This is true in 1.9.3 as well. I haven't looked at older versions.

Pardon me while I go grep "rescue Exception" in the entire Ruby codebase, and see whether I can reliably use Timeout at all...

OK, you might check out C:\Ruby200\lib\ruby\gems\2.0.0\gems\activerecord-3.2.13\lib\active_record\railties\databases.rake

All the other "rescue Exception" seem to re-raise it, except maybe C:\Ruby200\lib\ruby\2.0.0\xmlrpc\server.rb and C:\Ruby200\lib\ruby\gems\2.0.0\gems\activesupport-3.2.13\lib\active_support\callbacks.rb





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