The only remaining use of this function was to get the internal
message object from an exception's hidden `mesg` instance
variable to allow it to be dumped wiithout converting to a string.
As discussed in #103, this exposes internal implementation details
of CRuby, and ultimately does not provide any real utility to the
user since they can't directly inspect this hidden variable. The
test change here is to reflect CRuby behavior that denies equality
if the internal message objects do not match, as is the case after
the exception has been loaded and now has a simple String value.
The impact to users is that exceptions with special hidden message
objects will convert those objects to String during marshaling
through YAML. I believe this only affects NameError and its
descendants, since users can't set this field directly on their
own exception types.
Fixes#103.
This leads to double requiring "ext/psych/lib/psych/versions.rb" and
".ext/common/psych/versions.rb", which produces doxens of warnings
during `make test-all`.
http://rubyci.s3.amazonaws.com/ubuntu2004/ruby-master/log/20200608T123004Z.log.html.gz
```
[15092/20234]
TestRDocOptions#test_init_with_encoding/home/chkbuild/chkbuild/tmp/build/20200608T123004Z/ruby/ext/psych/lib/psych.rb:233: warning: already initialized constant Psych::LIBYAML_VERSION
/home/chkbuild/chkbuild/tmp/build/20200608T123004Z/ruby/.ext/common/psych.rb:233: warning: previous definition of LIBYAML_VERSION was here
/home/chkbuild/chkbuild/tmp/build/20200608T123004Z/ruby/ext/psych/lib/psych.rb:235: warning: already initialized constant Psych::NOT_GIVEN
/home/chkbuild/chkbuild/tmp/build/20200608T123004Z/ruby/.ext/common/psych.rb:235: warning: previous definition of NOT_GIVEN was here
/home/chkbuild/chkbuild/tmp/build/20200608T123004Z/ruby/ext/psych/lib/psych.rb:271: warning: method redefined; discarding old load
/home/chkbuild/chkbuild/tmp/build/20200608T123004Z/ruby/.ext/common/psych.rb:271: warning: previous definition of load was here
...
```
The same issue happened in fiddle.gemspec, and this change applies the
same fix as [fiddle](https://github.com/ruby/fiddle/issues/34).
Removing it triggers the following warnings when running `bundle` under
jruby from the root of the `psych` repo prints the following warnings:
```
/path/to/jruby-9.2.9.0/lib/ruby/gems/shared/gems/psych-3.1.0-java/lib/psych/versions.rb:7: warning: already initialized constant VERSION
/path/to//jruby-9.2.9.0/lib/ruby/gems/shared/gems/psych-3.1.0-java/lib/psych/versions.rb:10: warning: already initialized constant DEFAULT_SNAKEYAML_VERSION
```
This is because bundler loads the versions file relatively from the
local gemspec, and then internally loads the psych gem, causing the
redefinition warnings.
Instead, we modify the $LOAD_PATH so that when working locally on the
`psych` repo, the local version of `psych` gets used.
https://github.com/ruby/psych/commit/a3fc8191a7
Current version is not installable because the gemspec is invalid, since
it includes a `.travis.yml` file that no longer exists, so `rake
install` fails like this:
```
$ rake install
rake aborted!
WARNING: See https://guides.rubygems.org/specification-reference/ for help
ERROR: While executing gem ... (Gem::InvalidSpecificationException)
[".travis.yml"] are not files
```
https://github.com/ruby/psych/commit/32b18ca7ca
Ruby 2.7 deprecates taint and it no longer has an effect.
The lack of taint support should not cause a problem in
previous Ruby versions.
I'm not sure if the untaint calls in deduplicate are still needed
after the removal of tainting in the parser. If they are not
needed, they should be removed.
https://github.com/ruby/psych/commit/73c1a2b4e0
