The "raise" with no arguments raises the exception in $!, nested case too

[aycabta]

Ruby 2.4 and later, raise's behavior has been changed. Nested raise with an argument raises only the argument, it doesn't have outer exception. So I removed the argument. The raise with no arguments raises what contains nested exceptions.

This fixes a failure of TestRakeApplication#test_display_exception_details_cause_loop that @hsbt refers at #184. This passed all Ruby versions in Travis CI.

...And this will fix Travis CI failure of #183.

[olleolleolle]

Your explanation of 2.4's behavior makes this fix of the test code very clear.

[nobu]

This just re-raises "cause_b" exception, and makes no sense.

[aycabta]

This just re-raises "cause_b" exception

I think so, but I didn't want to say so.

I do the complementary explanation that I did. The "nested exception" means chaining Exception with Exceptin#cause. The test checks just it.

[aycabta]

https://twitter.com/hsbt/status/816458882541228032 (Japanese, I read with translation)

I grasped the overview around this tweet and its reply tree. If that tells you anything, I just made this Pull Request for 2.4's behavior, and I didn't understand the purpose of the test. I will leave it to appropriate one's judgement.

ref. The test is added for jimweirich#272 at first.

[nobu]

With this change, the test is almost same as test_display_exception_details_cause, except for an extra re-raising, and no meaning of loop.

[aycabta]

OK, I got the picture. I'm thinking what test_display_exception_details_cause_loop should be deleted.