Julia v1.9 Release Notes ======================== New language features --------------------- * It is now possible to assign to bindings in another module using `setproperty!(::Module, ::Symbol, x)`. ([#44137]) * Slurping in assignments is now also allowed in non-final position. This is handled via `Base.split_rest`. ([#42902]) * Character literals now support the same syntax allowed in string literals; i.e. the syntax can represent invalid UTF-8 sequences as allowed by the `Char` type ([#44989]). Language changes ---------------- * New builtins `getglobal(::Module, ::Symbol[, order])` and `setglobal!(::Module, ::Symbol, x[, order])` for reading from and writing to globals. `getglobal` should now be preferred for accessing globals over `getfield`. ([#44137]) * The `@invoke` macro introduced in 1.7 is now exported. Additionally, it now uses `Core.Typeof(x)` rather than `Any` when a type annotation is omitted for an argument `x` so that types passed as arguments are handled correctly. ([#45807]) * The `invokelatest` function and `@invokelatest` macro introduced in 1.7 are now exported. ([#45831]) Compiler/Runtime improvements ----------------------------- * The known quadratic behavior of type inference is now fixed and inference uses less memory in general. Certain edge cases with auto-generated long functions (e.g. ModelingToolkit.jl with partial differential equations and large causal models) should see significant compile-time improvements. ([#45276], [#45404]) * Non-concrete call sites can now be union-split to be inlined or statically-resolved even if there are multiple dispatch candidates. This may improve runtime performance in certain situations where object types are not fully known statically but mostly available at runtime (as like Julia-level type inference implementation itself) by statically resolving `@nospecialize`-d call sites and avoiding excessive compilation. ([#44512]) * All the previous usages of `@pure`-macro in `Base` has been replaced with the preferred `Base.@assume_effects`-based annotations. ([#44776]) Command-line option changes --------------------------- * In Linux and Windows, `--threads=auto` now tries to infer usable number of CPUs from the process affinity which is set typically in HPC and cloud environments ([#42340]). * `--math-mode=fast` is now a no-op ([#41638]). Users are encouraged to use the @fastmath macro instead, which has more well-defined semantics. * The `--threads` command-line option now accepts `auto|N[,auto|M]` where `M` specifies the number of interactive threads to create (`auto` currently means 1) ([#42302]). * New option `--heap-size-hint=` gives a memory hint for triggering greedy garbage collection. The size might be specified in bytes, kilobytes(1000k), megabytes(300M), gigabytes(1.5G) Multi-threading changes ----------------------- * `Threads.@spawn` now accepts an optional first argument: `:default` or `:interactive`. An interactive task desires low latency and implicitly agrees to be short duration or to yield frequently. Interactive tasks will run on interactive threads, if any are specified when Julia is started ([#42302]). Build system changes -------------------- New library functions --------------------- * `Iterators.flatmap` was added ([#44792]). * New helper `Splat(f)` which acts like `x -> f(x...)`, with pretty printing for inspecting which function `f` was originally wrapped. ([#42717]) * New `pkgversion(m::Module)` function to get the version of the package that loaded a given module, similar to `pkgdir(m::Module)`. ([#45607]) Library changes --------------- * A known concurrency issue of `iterate` methods on `Dict` and other derived objects such as `keys(::Dict)`, `values(::Dict)`, and `Set` is fixed. These methods of `iterate` can now be called on a dictionary or set shared by arbitrary tasks provided that there are no tasks mutating the dictionary or set ([#44534]). * Predicate function negation `!f` now returns a composed function `(!) ∘ f` instead of an anonymous function ([#44752]). * `RoundFromZero` now works for non-`BigFloat` types ([#41246]). * `Dict` can be now shrunk manually by `sizehint!` ([#45004]). * `@time` now separates out % time spent recompiling invalidated methods ([#45015]). * `eachslice` now works over multiple dimensions; `eachslice`, `eachrow` and `eachcol` return a `Slices` object, which allows dispatching to provide more efficient methods ([#32310]). Standard library changes ------------------------ #### Package Manager #### LinearAlgebra * The methods `a / b` and `b \ a` with `a` a scalar and `b` a vector, which were equivalent to `a * pinv(b)`, have been removed due to the risk of confusion with elementwise division ([#44358]). * We are now wholly reliant on libblastrampoline (LBT) for calling BLAS and LAPACK. OpenBLAS is shipped by default, but building the system image with other BLAS/LAPACK libraries is not supported. Instead, it is recommended that the LBT mechanism be used for swapping BLAS/LAPACK with vendor provided ones. ([#44360]) * `lu` now supports a new pivoting strategy `RowNonZero()` that chooses the first non-zero pivot element, for use with new arithmetic types and for pedagogy ([#44571]). * `normalize(x, p=2)` now supports any normed vector space `x`, including scalars ([#44925]). #### Markdown #### Printf * Error messages for bad format strings have been improved, to make it clearer what & where in the format string is wrong. ([#45366]) #### Random * `randn` and `randexp` now work for any `AbstractFloat` type defining `rand` ([#44714]). #### REPL * `Meta-e` now opens the current input in an editor. The content (if modified) will be executed upon existing the editor. * The contextual module which is active at the REPL can be changed (it is `Main` by default), via the `REPL.activate(::Module)` function or via typing the module in the REPL and pressing the keybinding Alt-m ([#33872]). #### SparseArrays #### Test * New fail-fast mode for testsets that will terminate the test run early if a failure or error occurs. Set either via the `@testset` kwarg `failfast=true` or by setting env var `JULIA_TEST_FAILFAST` to `"true"` i.e. in CI runs to request the job failure be posted eagerly when issues occur ([#45317]) #### Dates #### Downloads #### Statistics #### Sockets #### Tar #### Distributed * The package environment (active project, `LOAD_PATH`, `DEPOT_PATH`) are now propagated when adding *local* workers (e.g. with `addprocs(N::Int)` or through the `--procs=N` command line flag) ([#43270]). * `addprocs` for local workers now accept the `env` keyword argument for passing environment variables to the workers processes. This was already supported for remote workers ([#43270]). #### UUIDs #### Unicode * `graphemes(s, m:n)` returns a substring of the `m`-th to `n`-th graphemes in `s` ([#44266]). #### Mmap #### DelimitedFiles Deprecated or removed --------------------- * Unexported `splat` is deprecated in favor of exported `Splat`, which has pretty printing of the wrapped function. ([#42717]) External dependencies --------------------- Tooling Improvements --------------------- * Printing of `MethodError` and methods (such as from `methods(my_func)`) are now prettified and color consistent with printing of methods in stacktraces. ([#45069])