Avoid regex allocations by checking arity condition first

[ghost]

Description

Hi, I am trying to optimize YARD a bit to speed up documentation runs on a large codebase.

The codebase is private, so I am using https://github.com/watir/watir/ as a smaller stand-in to report benchmarking numbers from https://github.com/SamSaffron/memory_profiler.

Test set-up

• Ruby 2.7.6 (installed via rvm on Linux)
• Watir version: 293bed2b57c
• MemoryProfiler version: 1.0.0
• YARD baseline: 0a55093
• Test command:
  • ruby-memory-profiler --no-color --retained-strings=500 --allocated-strings=500 --max=300 -o prof.log ./run-yard.rb stats
    • run-yard.rb is a smaller version of /bin/yard (MemoryProfiler was not able to run /bin/yard)
    • I am using the stats command to avoid memory exhaustion

Performance data

• Before
  • Total allocated: 187901758 bytes (1987572 objects)
  • Total retained: 4052113 bytes (53463 objects)
• After
  • Total allocated: 187895022 bytes (1987442 objects)
  • Total retained: 4052113 bytes (53463 objects)
• Savings
  • Total allocated: 6736 bytes (130 objects)
  • Total retained: 0 bytes (0 objects)

Completed Tasks

• I have read the Contributing Guide.
• The pull request is complete (implemented / written).
• Git commits have been cleaned up (squash WIP / revert commits).
• I wrote tests and ran bundle exec rake locally (if code is attached to PR).

[dduugg]

Could the regex check be replaced with event.to_s.end_with?('_new')

[lsegal]

arity is better since ends_with breaks prior Ruby compatibility.

[dduugg]

What’s the minimum supported ruby version? The gemspec says it depends on webrick 1.7.0, which requires ruby >= 2.3.0, which supports String#end_with?

edit: confirmed yard installation fails in ruby 2.2.10:

$ gem install yard                                                                                                                                                    17:39
Fetching: webrick-1.7.0.gem (100%)
ERROR:  Error installing yard:
	webrick requires Ruby version >= 2.3.0.

[ghost]

CONTRIBUTING.md says:

Please also remember that YARD supports a number of environments, including OS X, Linux, Windows, and a number of older Ruby versions (1.8+)

If the minimum version is no longer 1.8, then some of the =~ checks can indeed be replaced with less expensive end_with? and start_with? checks.

[lsegal]

Good to know that end_with is available, but a little moot since arity is already here :)

[lsegal]

Great change, thanks!