fix rescue’s default behavior

[3cp]

When no type is given, “rescue” should catch StandardError by default,
NOT all types of Exceptions.

I am surprised rubyspec's corelib/language/rescue_spec.rb did not test this.

[3cp]

There is some weird bug on my last commit, fails on mri 2.0 and 2.2 (the only two run mspec on travis?)
The compiled javascript is broken on spec/corelib/language/precedence_spec.rb

I can confirm this is the only test having trouble.

  it "? : has higher precedence than rescue" do
    (true ? oops : 0 rescue 10).should == 10
  end

[3cp]

anyway, found another bug related.
try in http://opalrb.org/try/

a = true ? 2 : 0 rescue 10
puts a

nothing printed due to a missing return in compiled js.

EDIT:

a = true ? 2 : 0 rescue 10                         # fail
a = (true ? 2 : 0) rescue 10                       # pass
a = begin; true ? 2 : 1; rescue; 10; end           # fail
a = begin; (true ? 2 : 1); rescue; 10; end         # fail

[3cp]

one more serious bug on rescue.
still exists in my branch.

begin
  raise IOError, 'foo'
rescue RangeError              # this one is correct
rescue TypeError               # miss a return
rescue IOError                 # following two lines disappear in js
  puts "I got #{$!.message}"
end

/* Generated by Opal 0.7.0.beta2 */
(function(Opal) {
  Opal.dynamic_require_severity = "error";
  var self = Opal.top, $scope = Opal, nil = Opal.nil, $breaker = Opal.breaker, $slice = Opal.slice;

  Opal.add_stubs(['$raise']);
  try {
  return self.$raise($scope.get('IOError'), "foo")
  } catch ($err) {if (Opal.rescue($err, [$scope.get('RangeError')])) {
    return nil
    }else if (Opal.rescue($err, [$scope.get('TypeError')])) {
    nil
    }else { throw $err; }
  }
})(Opal);

[elia]

Got caught by the latter a few days ago, anyway I'm (slowly) working to bring in CRuby tests, maybe they cover these cases.

[elia]

Thanks! merged in f1c7e73

@huochunpeng I also fixed the last bug you pointed out in #1269

[3cp]

@elia, the bug on one line rescue is still not resolved. You may want to open another ticket.

a = true ? 2 : 0 rescue 10                         # fail
a = (true ? 2 : 0) rescue 10                       # pass
a = begin; true ? 2 : 1; rescue; 10; end           # fail
a = begin; (true ? 2 : 1); rescue; 10; end         # fail

To illustrate

a = true ? 2 : 0 rescue 10

Compile result doesn't give variable "a" any val because of missing return in try block.

/* Generated by Opal 0.10.0.dev */
(function(Opal) {
  Opal.dynamic_require_severity = "error";
  var OPAL_CONFIG = { method_missing: true, arity_check: false, freezing: true, tainting: true };
  var $a, self = Opal.top, $scope = Opal, nil = Opal.nil, $breaker = Opal.breaker, $slice = Opal.slice, a = nil;

  return a = (function() {try {(function() {if ((($a = true) !== nil && (!$a.$$is_boolean || $a == true))) {
    return 2
    } else {
    return 0
  }; return nil; })() } catch ($err) { if (Opal.rescue($err, [$scope.get('StandardError')])) {return 10}else { throw $err; } }})()
})(Opal);

a = (true ? 2 : 0) rescue 10

Extra brackets yield correct result

 /* Generated by Opal 0.10.0.dev */
(function(Opal) {
  Opal.dynamic_require_severity = "error";
  var OPAL_CONFIG = { method_missing: true, arity_check: false, freezing: true, tainting: true };
  var $a, self = Opal.top, $scope = Opal, nil = Opal.nil, $breaker = Opal.breaker, $slice = Opal.slice, a = nil;

  return a = (function() {try {return ((function() {if ((($a = true) !== nil && (!$a.$$is_boolean || $a == true))) {
    return 2
    } else {
    return 0
  }; return nil; })()) } catch ($err) { if (Opal.rescue($err, [$scope.get('StandardError')])) {return 10}else { throw $err; } }})()
})(Opal);

[elia]

@huochunpeng thanks!
yes, a separate issue would be better, do you mind opening it with a link to this one in the description?