NEWS.md

Julia v1.8 Release Notes

New language features

• Module(:name, false, false) can be used to create a module that contains no names (it does not import Base or Core and does not contain a reference to itself). ([#40110, #42154])
• @inline and @noinline annotations can be used within a function body to give an extra hint about the inlining cost to the compiler. ([#41312])
• @inline and @noinline annotations can now be applied to a function callsite or block to enforce the involved function calls to be (or not to be) inlined. ([#41312])
• The default behavior of observing @inbounds declarations is now an option via auto in --check-bounds=yes|no|auto ([#41551])
• New function eachsplit(str) for iteratively performing split(str).
• ∀, ∃, and ∄ are now allowed as identifier characters ([#42314]).
• try-blocks can now optionally have an else-block which is executed right after the main body only if no errors were thrown. ([#42211])

Language changes

• Newly created Task objects (@spawn, @async, etc.) now adopt the world-age for methods from their parent Task upon creation, instead of using the global latest world at start. This is done to enable inference to eventually optimize these calls. Places that wish for the old behavior may use Base.invokelatest. ([#41449])
• @time and @timev now take an optional description to allow annotating the source of time reports. i.e. @time "Evaluating foo" foo() ([#42431])
• New @showtime macro to show both the line being evaluated and the @time report ([#42431])
• last(collection) will now work on any collection that supports Iterators.reverse and first, rather than being restricted to indexable collections.
• Unbalanced Unicode bidirectional formatting directives are now disallowed within strings and comments, to mitigate the "trojan source" vulnerability ([#42918]).

Compiler/Runtime improvements

• The LLVM-based compiler has been separated from the run-time library into a new library, libjulia-codegen. It is loaded by default, so normal usage should see no changes. In deployments that do not need the compiler (e.g. system images where all needed code is precompiled), this library (and its LLVM dependency) can simply be excluded ([#41936]).

Command-line option changes

• New option --strip-metadata to remove docstrings, source location information, and local variable names when building a system image ([#42513]).
• New option --strip-ir to remove the compiler's IR (intermediate representation) of source code when building a system image. The resulting image will only work if --compile=all is used, or if all needed code is precompiled ([#42925]).

Multi-threading changes

Build system changes

New library functions

• hardlink(src, dst) can be used to create hard links. ([#41639])
• diskstat(path=pwd()) can be used to return statistics about the disk. ([#42248])

New library features

• @test_throws "some message" triggers_error() can now be used to check whether the displayed error text contains "some message" regardless of the specific exception type. Regular expressions, lists of strings, and matching functions are also supported. ([#41888])
• @testset foo() can now be used to create a test set from a given function. The name of the test set is the name of the called function. The called function can contain @test and other @testset definitions, including to other function calls, while recording all intermediate test results. ([#42518])

Standard library changes

• range accepts either stop or length as a sole keyword argument ([#39241])
• precision and setprecision now accept a base keyword ([#42428]).
• The length function on certain ranges of certain specific element types no longer checks for integer overflow in most cases. The new function checked_length is now available, which will try to use checked arithmetic to error if the result may be wrapping. Or use a package such as SaferIntegers.jl when constructing the range. ([#40382])
• TCP socket objects now expose closewrite functionality and support half-open mode usage ([#40783]).
• Intersect returns a result with the eltype of the type-promoted eltypes of the two inputs ([#41769]).
• Iterators.countfrom now accepts any type that defines +. ([#37747])

InteractiveUtils

• A new macro @time_imports for reporting any time spent importing packages and their dependencies ([#41612])

Package Manager

LinearAlgebra

Markdown

Printf

• Now uses textwidth for formatting %s and %c widths ([#41085]).

Profile

• Profiling now records sample metadata including thread and task. Profile.print() has a new groupby kwarg that allows grouping by thread, task, or nested thread/task, task/thread, and threads and tasks kwargs to allow filtering. Further, percent utilization is now reported as a total or per-thread, based on whether the thread is idle or not at each sample. Profile.fetch() by default strips out the new metadata to ensure backwards compatibility with external profiling data consumers, but can be included with the include_meta kwarg. ([#41742])

Random

REPL

• RadioMenu now supports optional keybindings to directly select options ([#41576]).
• ?(x, y followed by TAB displays all methods that can be called with arguments x, y, .... (The space at the beginning prevents entering help-mode.) MyModule.?(x, y limits the search to MyModule. TAB requires that at least one argument have a type more specific than Any; use SHIFT-TAB instead of TAB to allow any compatible methods.

SparseArrays

Dates

Downloads

Statistics

Sockets

Tar

Distributed

UUIDs

Mmap

DelimitedFiles

Logging

• The standard log levels BelowMinLevel, Debug, Info, Warn, Error, and AboveMaxLevel are now exported from the Logging stdlib ([#40980]).

Unicode

• Added function isequal_normalized to check for Unicode equivalence without explicitly constructing normalized strings ([#42493]).
• The Unicode.normalize function now accepts a chartransform keyword that can be used to supply custom character mappings, and a Unicode.julia_chartransform function is provided to reproduce the mapping used in identifier normalization by the Julia parser ([#42561]).

Deprecated or removed

External dependencies

Tooling Improvements