Last checked and updated on 13 Jun 2026
What Is New in Ruby 2.6
| Category | Key Changes |
|---|---|
| New Features | JIT compiler, endless ranges, new exception handling, Kernel#then |
| Performance | Module#name, Transient Heap, block handling, Proc call speedup |
| Standard Library | Bundler 1.17, new RubyGems, Random.urandom, BigDecimal updates |
| Deprecations | Proc and Method arity, BigDecimal legacy methods |
How does the new JIT compiler work?
Ruby 2.6 introduces an initial implementation of a JIT (Just-In-Time) compiler. This compiler operates by generating C code at runtime, which is then passed to a native C compiler to produce optimized machine code. In practice, this can significantly speed up the execution of many CPU-intensive Ruby programs.
You enable it with the --jit command-line option. The current implementation is experimental and works best for long-running, pure Ruby applications that aren't heavily bound by I/O operations.
What are endless ranges and how do I use them?
Endless ranges provide a concise way to express a range that has no upper bound. You create one by omitting the end value, for example: (1..). This is perfect for representing sequences that continue indefinitely.
You'll find them most useful for slicing arrays or other enumerable objects from a starting index to the very end. This replaces the older, more verbose pattern of using something like ary[10..-1].
# Before 2.6
ary[10..-1]
# With endless range
ary[10..]What changed with exception handling?
The exception handling mechanism got a major upgrade. You can now use the new exception: false parameter with methods like Integer, Float, String, and Rational to get a nil return instead of raising an exception on conversion failure.
This matters because it cleans up a common pattern where you'd rescue an exception for a simple type conversion, making the code both faster and more readable.
# Returns nil instead of raising ArgumentError
Integer("abc", exception: false)What performance improvements should I expect?
Beyond JIT, several core areas saw speed boosts. The Transient Heap was implemented for short-lived objects, making certain object allocations much faster. The speed of calling a block was improved, and the performance of Proc#call was significantly enhanced.
Module#name now returns a frozen String, which reduces object allocations and can lead to measurable performance gains in large applications that frequently query module and class names.
What's new in the standard library?
Bundler 1.17, RubyGems 3.0.1, and RDoc 6.0.1 are now bundled with Ruby. The Random.urandom method was aliased to SecureRandom.urandom for easier access to cryptographically secure random bytes.
The BigDecimal library was updated to version 1.4.0, introducing new methods and deprecating some older, less precise ones. This is a step towards better numerical computation in Ruby.
FAQ
Is the JIT compiler ready for production use?
It's marked as experimental. It shows great promise for CPU-bound workloads but might not benefit I/O-bound applications like web servers yet. Test it with your specific application to see the impact.
What's the difference between yield_self and the new then method?Kernel#then is simply a new name for yield_self. They are aliases and function identically, allowing for more readable method chaining.
Why would I use an endless range instead of ary[start..-1]?
Endless ranges are more intention-revealing and concise. They clearly communicate that you want everything from the start index onward, without the mental overhead of the -1 index magic number.
What is the practical benefit of the exception: false parameter?
It eliminates the performance penalty and code clutter of using a begin-rescue block for simple, expected conversion failures, making your code both faster and cleaner.
Are there any breaking changes I need to watch for?
The main changes to be aware of are deprecations. The arity of Proc#to_proc and Method#to_proc is now consistent, and some legacy methods in the BigDecimal library are deprecated and will be removed in future versions.