Set string encoding after reading a heap_mapped_string

[casperisfine]

Fix #200

I think the bug was introduced in #196

@tagomoris

[tagomoris]

Thank you! I'll release this quickly as 1.4.1.

[tagomoris]

The test fails on my laptop (Ruby 3.0.0):

MBA:msgpack-ruby tagomoris$ bundle exec rake
cp ChangeLog tmp/x86_64-darwin19/stage/ChangeLog
cp README.md tmp/x86_64-darwin19/stage/README.md
cp Rakefile tmp/x86_64-darwin19/stage/Rakefile
cp ext/msgpack/buffer.h tmp/x86_64-darwin19/stage/ext/msgpack/buffer.h
cp lib/msgpack/version.rb tmp/x86_64-darwin19/stage/lib/msgpack/version.rb
cp msgpack.gemspec tmp/x86_64-darwin19/stage/msgpack.gemspec
cp spec/unpacker_spec.rb tmp/x86_64-darwin19/stage/spec/unpacker_spec.rb
install -c tmp/x86_64-darwin19/msgpack/3.0.0/msgpack.bundle lib/msgpack/msgpack.bundle
cp tmp/x86_64-darwin19/msgpack/3.0.0/msgpack.bundle tmp/x86_64-darwin19/stage/lib/msgpack/msgpack.bundle
/Users/tagomoris/.rbenv/versions/3.0.0/bin/ruby -I/Users/tagomoris/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/rspec-core-3.10.1/lib:/Users/tagomoris/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/rspec-support-3.10.1/lib /Users/tagomoris/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/rspec-core-3.10.1/exe/rspec --pattern spec/\{,cruby/\}\*_spec.rb -c -f progress -Ilib
buffer_io random seed: 0xfbc2fd48f5d2c0dd3b118bc789d6a317
buffer random seed: 0x2d386d09027536ed4c07edf40e43dfcc
....................................................................................................................................................................................................................................*....................................................................................................................................................F.........

Pending: (Failures listed here are expected and do not affect your suite's status)

  1) MessagePack with other things rasies an error on #unpack with garbage
     # but nothing was raised. why?
     # ./spec/msgpack_spec.rb:118


Failures:

  1) MessagePack::Unpacker regressions preserve string encoding (issue #200)
     Failure/Error: MessagePack.unpack(MessagePack.pack(string)).encoding.should == string.encoding
     
       expected: #<Encoding:UTF-8>
            got: #<Encoding:ASCII-8BIT> (using ==)
       Diff:
       @@ -1 +1 @@
       -#<Encoding:UTF-8>
       +#<Encoding:ASCII-8BIT>
       
     # ./spec/unpacker_spec.rb:643:in `block (3 levels) in <top (required)>'

Finished in 7.85 seconds (files took 0.29418 seconds to load)
387 examples, 1 failure, 1 pending

Failed examples:

rspec ./spec/unpacker_spec.rb:638 # MessagePack::Unpacker regressions preserve string encoding (issue #200)

/Users/tagomoris/.rbenv/versions/3.0.0/bin/ruby -I/Users/tagomoris/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/rspec-core-3.10.1/lib:/Users/tagomoris/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/rspec-support-3.10.1/lib /Users/tagomoris/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/rspec-core-3.10.1/exe/rspec --pattern spec/\{,cruby/\}\*_spec.rb -c -f progress -Ilib failed

[casperisfine]

👀

[tagomoris]

Sorry, I tested with 1.4.0 without recompiling the code of this branch. It passes after rake clean.