519a4bdbc1
The actual algorithm is largely unchanged, just allowed to use singlebyte checks for common encodings. It could certainly be optimized much further, as here again it often scans from the front of the string when we're interested in the back of it. But the algorithm as many Windows only corner cases so I'd rather ship a good improvement now and eventually come back to it later. Most of improvement here is from the reduced setup cost (avodi double null checks, avoid duping the argument, etc), and skipping the multi-byte checks. ``` compare-ruby: ruby 4.1.0dev (2026-01-19T03:51:30Z master 631bf19b37) +PRISM [arm64-darwin25] built-ruby: ruby 4.1.0dev (2026-01-21T08:21:05Z opt-basename 7eb11745b2) +PRISM [arm64-darwin25] ``` | |compare-ruby|built-ruby| |:----------|-----------:|---------:| |long | 3.412M| 18.158M| | | -| 5.32x| |long_name | 1.981M| 8.580M| | | -| 4.33x| |withext | 3.200M| 12.986M| | | -| 4.06x|
spec/bundler
spec/bundler is rspec examples for bundler library (lib/bundler.rb, lib/bundler/*).
Running spec/bundler
To run rspec for bundler:
make test-bundler
or run rspec with parallel execution:
make test-bundler-parallel
If you specify BUNDLER_SPECS=foo/bar_spec.rb then only spec/bundler/foo/bar_spec.rb will be run.
spec/ruby
ruby/spec (https://github.com/ruby/spec/) is a test suite for the Ruby language.
Once a month, @eregon merges the in-tree copy under spec/ruby with the upstream repository, preserving the commits and history. The same happens for other implementations such as JRuby and TruffleRuby.
Feel welcome to modify the in-tree spec/ruby. This is the purpose of the in-tree copy, to facilitate contributions to ruby/spec for MRI developers.
New features, additional tests for existing features and
regressions tests are all welcome in ruby/spec.
There is very little behavior that is implementation-specific,
as in the end user programs tend to rely on every behavior MRI exhibits.
In other words: If adding a spec might reveal a bug in
another implementation, then it is worth adding it.
Currently, the only module which is MRI-specific is RubyVM.
Changing behavior and versions guards
Version guards (ruby_version_is) must be added for new features or features
which change behavior or are removed. This is necessary for other Ruby implementations
to still be able to run the specs and contribute new specs.
For example, change:
describe "Some spec" do
it "some example" do
# Old behavior for Ruby < 2.7
end
end
to:
describe "Some spec" do
ruby_version_is ""..."2.7" do
it "some example" do
# Old behavior for Ruby < 2.7
end
end
ruby_version_is "2.7" do
it "some example" do
# New behavior for Ruby >= 2.7
end
end
end
See spec/ruby/CONTRIBUTING.md for more documentation about guards.
To verify specs are compatible with older Ruby versions:
cd spec/ruby
$RUBY_MANAGER use 2.4.9
../mspec/bin/mspec -j
Running ruby/spec
To run all specs:
make test-spec
Extra arguments can be added via SPECOPTS.
For instance, to show the help:
make test-spec SPECOPTS=-h
You can also run the specs in parallel, which is currently experimental. It takes around 10s instead of 60s on a quad-core laptop.
make test-spec SPECOPTS=-j
To run a specific test, add its path to the command:
make test-spec SPECOPTS=spec/ruby/language/for_spec.rb
If ruby trunk is your current ruby in $PATH, you can also run mspec directly:
# change ruby to trunk
ruby -v # => trunk
spec/mspec/bin/mspec spec/ruby/language/for_spec.rb
ruby/spec and test/
The main difference between a "spec" under spec/ruby/ and
a test under test/ is that specs are documenting what they test.
This is extremely valuable when reading these tests, as it
helps to quickly understand what specific behavior is tested,
and how a method should behave. Basic English is fine for spec descriptions.
Specs also tend to have few expectations (assertions) per spec,
as they specify one aspect of the behavior and not everything at once.
Beyond that, the syntax is slightly different but it does the same thing:
assert_equal 3, 1+2 is just (1+2).should == 3.
Example:
describe "The for expression" do
it "iterates over an Enumerable passing each element to the block" do
j = 0
for i in 1..3
j += i
end
j.should == 6
end
end
For more details, see spec/ruby/CONTRIBUTING.md.
spec/syntax_suggest
Running spec/syntax_suggest
To run rspec for syntax_suggest:
make test-syntax-suggest
If you specify SYNTAX_SUGGEST_SPECS=foo/bar_spec.rb then only spec/syntax_suggest/foo/bar_spec.rb will be run.