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Julia v1.11 Release Notes

New language features

  • New Memory type that provides a lower-level container as an alternative to Array. Memory has less overhead and a faster constructor, making it a good choice for situations that do not need all the features of Array (e.g. multiple dimensions). Most of the Array type is now implemented in Julia on top of Memory, leading to significant speedups for several functions (e.g. push!) as well as more maintainable code (#51319).
  • public is a new keyword. Symbols marked with public are considered public API. Symbols marked with export are now also treated as public API. The difference between public and export is that public names do not become available when using a package/module (#50105).
  • ScopedValue implements dynamic scope with inheritance across tasks (#50958).
  • Manifest.toml files can now be renamed in the format Manifest-v{major}.{minor}.toml to be preferentially picked up by the given julia version. i.e. in the same folder, a Manifest-v1.11.toml would be used by v1.11 and Manifest.toml by every other julia version. This makes managing environments for multiple julia versions at the same time easier (#43845).
  • Support for Unicode 15.1 (#51799).

Language changes

  • During precompilation, atexit hooks now run before saving the output file. This allows users to safely tear down background state (such as closing Timers and sending disconnect notifications to heartbeat tasks) and cleanup other resources when the program wants to begin exiting.
  • Code coverage and malloc tracking is no longer generated during the package precompilation stage. Further, during these modes pkgimage caches are now used for packages that are not being tracked. This means that coverage testing (the default for julia-actions/julia-runtest) will by default use pkgimage caches for all other packages than the package being tested, likely meaning faster test execution (#52123).
  • Specifying a path in JULIA_DEPOT_PATH now results in the expansion of empty strings to omit the default user depot (#51448).
  • Precompilation cache files are now relocatable and their validity is now verified through a content hash of their source files instead of their mtime (#49866).
  • Extensions may now depend on other extensions, if their triggers include all triggers of any extension they wish to depend upon (+ at least one other trigger). Ext-to-ext dependencies that don't meet this requirement are now blocked from using Base.get_extension during pre- compilation, to prevent extension cycles #55557.

Compiler/Runtime improvements

  • Updated GC heuristics to count allocated pages instead of individual objects (#50144).
  • Added support for annotating Base.@assume_effects on code blocks (#52400).

Command-line option changes

  • The entry point for Julia has been standardized to Main.main(args). This must be explicitly opted into using the @main macro (see the docstring for further details). When opted-in, and julia is invoked to run a script or expression (i.e. using julia script.jl or julia -e expr), julia will subsequently run the Main.main function automatically. This is intended to unify script and compilation workflows, where code loading may happen in the compiler and execution of Main.main may happen in the resulting executable. For interactive use, there is no semantic difference between defining a main function and executing the code directly at the end of the script (#50974).
  • The --compiled-modules and --pkgimages flags can now be set to existing, which will cause Julia to consider loading existing cache files, but not to create new ones (#50586, #52573).
  • The --project argument now accepts @script to give a path to a directory with a Project.toml relative to the passed script file. --project=@script/foo for the foo subdirectory. If no path is given after (i.e. --project=@script) then (like --project=@.) the directory and its parents are searched for a Project.toml (#50864 and #53352)

Multi-threading changes

  • Threads.@threads now supports the :greedy scheduler, intended for non-uniform workloads (#52096).
  • A new public (but unexported) struct Base.Lockable{T, L<:AbstractLock} makes it easy to bundle a resource and its lock together (#52898).

Build system changes

  • There is a new Makefile to build Julia and LLVM using the profile-guided and link-time optimizations (PGO and LTO) strategies, see contrib/pgo-lto/Makefile (#45641).

New library functions

  • Three new types around the idea of text with "annotations" (Pair{Symbol, Any} entries, e.g. :lang => "en" or :face => :magenta). These annotations are preserved across operations (e.g. string concatenation with *) when possible.
    • AnnotatedString is a new AbstractString type. It wraps an underlying string and allows for annotations to be attached to regions of the string. This type is used extensively in the new StyledStrings standard library to hold styling information.
    • AnnotatedChar is a new AbstractChar type. It wraps another char and holds a list of annotations that apply to it.
    • AnnotatedIOBuffer is a new IO type that mimics an IOBuffer, but has specialised read/write methods for annotated content. This can be thought of both as a "string builder" of sorts and also as glue between annotated and unannotated content.
  • in!(x, s::AbstractSet) will return whether x is in s, and insert x in s if not (#45156, #51636).
  • The new Libc.mkfifo function wraps the mkfifo C function on Unix platforms (#34587).
  • logrange(start, stop; length) makes a range of constant ratio, instead of constant step (#39071)
  • copyuntil(out, io, delim) and copyline(out, io) copy data into an out::IO stream (#48273).
  • eachrsplit(string, pattern) iterates split substrings right to left (#51646).
  • Sys.username() can be used to return the current user's username (#51897).
  • Sys.isreadable(), Sys.iswritable() can be used to check if the current user has access permissions that permit reading and writing, respectively. (#53320).
  • GC.logging_enabled() can be used to test whether GC logging has been enabled via GC.enable_logging (#51647).
  • IdSet is now exported from Base and considered public (#53262).
  • @time now reports a count of any lock conflicts where a ReentrantLock had to wait, plus a new macro @lock_conflicts which returns that count (#52883).
  • The new macro Base.Cartesian.@ncallkw is analogous to Base.Cartesian.@ncall, but allows adding keyword arguments to the function call (#51501).
  • New function Docs.hasdoc(module, symbol) tells whether a name has a docstring (#52139).
  • New function Docs.undocumented_names(module) returns a module's undocumented public names (#52413).

New library features

  • invmod(n, T) where T is a native integer type now computes the modular inverse of n in the modular integer ring that T defines (#52180).
  • invmod(n) is an abbreviation for invmod(n, typeof(n)) for native integer types (#52180).
  • replace(string, pattern...) now supports an optional IO argument to write the output to a stream rather than returning a string (#48625).
  • New methods allequal(f, itr) and allunique(f, itr) taking a predicate function (#47679).
  • sizehint!(s, n) now supports an optional shrink argument to disable shrinking (#51929).
  • Passing an IOBuffer as a stdout argument for Process spawn now works as expected, synchronized with wait or success, so a Base.BufferStream is no longer required there for correctness to avoid data races (#52461).
  • After a process exits, closewrite will no longer be automatically called on the stream passed to it. Call wait on the process instead to ensure the content is fully written, then call closewrite manually to avoid data races, or use the callback form of open to have all that handled automatically (#52461).
  • @timed now additionally returns the elapsed compilation and recompilation time (#52889).
  • filter can now act on a NamedTuple (#50795).
  • Iterators.cycle(iter, n) runs over iter a fixed number of times, instead of forever (#47354).
  • zero(::AbstractArray) now applies recursively, so zero([[1,2],[3,4,5]]) now produces the additive identity [[0,0],[0,0,0]] rather than erroring (#38064).
  • include_dependency(path; track_content=true) allows switching from using mtime to hashing of the precompilation dependency in order to restore relocatability of precompilation caches (#51798).

Standard library changes

  • The fallback method write(::IO, ::AbstractArray) used to recursively call write on each element, but now writes the in-memory representation of each value. For example, write(io, 'a':'b') now writes 4 bytes for each character, instead of writing the UTF-8 representation of each character. The new format is compatible with that used by Array, making it possible to use read! to get the data back (#42593).
  • It's not possible to define length for stateful iterators in a generally consistent manner. The potential for silently incorrect results for Stateful iterators is addressed by deleting the length(::Stateful) method. The last type parameter of Stateful is gone, too. Issue: (#47790), PR: (#51747).

Package Manager

  • It is now possible to specify "sources" for packages in a [sources] section in Project.toml. This can be used to add non-registered normal or test dependencies.
  • Pkg now obeys [compat] bounds for julia and raises an error if the version of the running Julia binary is incompatible with the bounds in Project.toml. Pkg has always obeyed this compat when working with Registry packages. This change affects mostly local packages
  • pkg> add and Pkg.add will now add compat entries for new direct dependencies if the active environment is a package (has a name and uuid entry).
  • Dependencies can now be directly added as weak deps or extras via the pkg> add --weak/extra Foo or Pkg.add("Foo", target=:weakdeps/:extras) forms.

StyledStrings

  • A new standard library for handling styling in a more comprehensive and structured way (#49586).
  • The new Faces struct serves as a container for text styling information (think typeface, as well as color and decoration), and comes with a framework to provide a convenient, extensible (via addface!), and customisable (with a user's Faces.toml and loadfaces!) approach to styled content (#49586).
  • The new @styled_str string macro provides a convenient way of creating a AnnotatedString with various faces or other attributes applied (#49586).

Libdl

  • A new LazyLibrary type is exported from Libdl for use in building chained lazy library loads, primarily to be used within JLLs (#50074).

LinearAlgebra

  • cbrt(::AbstractMatrix{<:Real}) is now defined and returns real-valued matrix cube roots of real-valued matrices (#50661).
  • eigvals/eigen(A, bunchkaufman(B)) and eigvals/eigen(A, lu(B)), which utilize the Bunchkaufman (LDL) and LU decomposition of B, respectively, now efficiently compute the generalized eigenvalues (eigen: and eigenvectors) of A and B. Note: The second argument is the output of bunchkaufman or lu (#50471).
  • There is now a specialized dispatch for eigvals/eigen(::Hermitian{<:Tridiagonal}) which performs a similarity transformation to create a real symmetric tridiagonal matrix, and solve that using the LAPACK routines (#49546).
  • Structured matrices now retain either the axes of the parent (for Symmetric/Hermitian/AbstractTriangular/UpperHessenberg), or that of the principal diagonal (for banded matrices) (#52480).
  • bunchkaufman and bunchkaufman! now work for any AbstractFloat, Rational and their complex variants. bunchkaufman now supports Integer types, by making an internal conversion to Rational{BigInt}. Added new function inertia that computes the inertia of the diagonal factor given by the BunchKaufman factorization object of a real symmetric or Hermitian matrix. For complex symmetric matrices, inertia only computes the number of zero eigenvalues of the diagonal factor (#51487).
  • Packages that specialize matrix-matrix mul! with a method signature of the form mul!(::AbstractMatrix, ::MyMatrix, ::AbstractMatrix, ::Number, ::Number) no longer encounter method ambiguities when interacting with LinearAlgebra. Previously, ambiguities used to arise when multiplying a MyMatrix with a structured matrix type provided by LinearAlgebra, such as AbstractTriangular, which used to necessitate additional methods to resolve such ambiguities. Similar sources of ambiguities have also been removed for matrix-vector mul! operations (#52837).
  • lu and issuccess(::LU) now accept an allowsingular keyword argument. When set to true, a valid factorization with rank-deficient U factor will be treated as success instead of throwing an error. Such factorizations are now shown by printing the factors together with a "rank-deficient" note rather than printing a "Failed Factorization" message (#52957).

Random

  • rand now supports sampling over Tuple types (#35856, #50251).
  • rand now supports sampling over Pair types (#28705).
  • When seeding RNGs provided by Random, negative integer seeds can now be used (#51416).
  • Seedable random number generators from Random can now be seeded by a string, e.g. seed!(rng, "a random seed") (#51527).

REPL

  • Tab complete hints now show in lighter text while typing in the repl. To disable set Base.active_repl.options.hint_tab_completes = false interactively, or in startup.jl:
    if VERSION >= v"1.11.0-0"
  atreplinit() do repl
      repl.options.hint_tab_completes = false
  end
end
    (#51229).
  • Meta-M with an empty prompt now toggles the contextual module between the previous non-Main contextual module and Main so that switching back and forth is simple (#51616, #52670).

Dates

The undocumented function adjust is no longer exported but is now documented (#53092).

Statistics

  • Statistics is now an upgradeable standard library (#46501).

Distributed

  • pmap now defaults to using a CachingPool (#33892).

Deprecated or removed

  • Base.map, Iterators.map, and foreach lost their single-argument methods (#52631).

External dependencies

  • The libuv library has been updated from a base of v1.44.2 to v1.48.0 (#49937).
  • tput is no longer called to check terminal capabilities; it has been replaced with a pure-Julia terminfo parser (#50797).
  • The terminal info database, terminfo, is now vendored by default, providing a better REPL user experience when terminfo is not available on the system. Julia can be built without vendoring the database using the Makefile option WITH_TERMINFO=0. (#55411)

Tooling Improvements

  • CI now performs limited automatic typo detection on all PRs. If you merge a PR with a failing typo CI check, then the reported typos will be automatically ignored in future CI runs on PRs that edit those same files (#51704).