View Source Changelog for Elixir v1.12
Elixir v1.12 is out with improvements to scripting, tighter Erlang/OTP 24 integration, stepped ranges, and dozen of new functions across the standard library. Overall this is a small release, which continues our tradition of bringing Elixir developers quality of life improvements every 6 months.
Elixir v1.12 requires Erlang/OTP 22+. We also recommend running mix local.rebar
after installation to upgrade to the latest Rebar versions, which includes support for Erlang OTP/24+.
Scripting improvements: Mix.install/2
and System.trap_signal/3
Elixir v1.12 brings new conveniences for those using Elixir for scripting (via .exs
files). Elixir has been capable of managing dependencies for a quite long time, but it could only be done within Mix projects. In particular, the Elixir team is wary of global dependencies as any scripts that rely on system packages are brittle and hard to reproduce whenever your system changes.
Mix.install/2
is meant to be a sweetspot between single-file scripts and full-blown Mix projects. With Mix.install/2
, you can list your dependencies on top of your scripts. When you execute the script for the first time, Elixir will download, compile, and cache your dependencies before running your script. Future invocations of the script will simply read the compiled artefacts from the cache:
Mix.install([:jason])
IO.puts Jason.encode!(%{hello: :world})
Mix.install/2
also performs protocol consolidation, which gives script developers an option to execute their code in the most performant format possible.
Note: Mix.install/2
is currently experimental and it may change in future releases.
Another improvement to scripting is the ability to trap exit signals via System.trap_signal/3
. All you need is the signal name and a callback that will be invoked when the signal triggers. For example, ExUnit leverages this functionality to print all currently running tests when you abort the test suite via SIGQUIT (Ctrl+\\
):
$ mix test
.......................................................................
.....................^\
Aborting test suite, the following have not completed:
* test query building [test/ecto/query_test.exs:48]
* test placeholders in Repo.insert_all [test/ecto/repo_test.exs:502]
Showing results so far...
78 doctests, 1042 tests, 0 failures
This is particularly useful when your tests get stuck and you want to know which one is the culprit.
Important: Trapping signals may have strong implications on how a system shuts down and behave in production and therefore it is extremely discouraged for libraries to set their own traps. Instead, they should redirect users to configure them themselves. The only cases where it is acceptable for libraries to set their own traps is when using Elixir in script mode, such as in .exs
files and via Mix tasks.
Tighter Erlang/OTP 24 integration
Erlang/OTP 24 ships with JIT compilation support and Elixir developers don't have to do anything to reap its benefits. There are many other features in Erlang/OTP 24 to look forwards to and Elixir v1.12 provides integration with many of them: such as support for 16bit floats in bitstrings as well as performance improvements in the compiler and during code evaluation.
Another excellent feature in Erlang/OTP 24 is the implementation of EEP 54, which provides extended error information for many functions in Erlang's stdlib. Elixir v1.12 fully leverages this feature to improve reporting for errors coming from Erlang. For example, in earlier OTP versions, inserting an invalid argument into a ETS table that no longer exists would simply error with ArgumentError
:
Interactive Elixir (1.11.0)
iex(1)> ets = :ets.new(:example, [])
#Reference<0.3845811859.2669281281.223553>
iex(2)> :ets.delete(ets)
true
iex(3)> :ets.insert(ets, :should_be_a_tuple)
** (ArgumentError) argument error
(stdlib 3.15) :ets.insert(#Reference<0.3845811859.2669281281.223553>, :should_be_a_tuple)
However, in Elixir v1.12 with Erlang/OTP 24:
Interactive Elixir (1.12.0)
iex(1)> ets = :ets.new(:example, [])
#Reference<0.105641012.1058144260.76455>
iex(2)> :ets.delete(ets)
true
iex(3)> :ets.insert(ets, :should_be_a_tuple)
** (ArgumentError) errors were found at the given arguments:
* 1st argument: the table identifier does not refer to an existing ETS table
* 2nd argument: not a tuple
(stdlib 3.15) :ets.insert(#Reference<0.105641012.1058144260.76455>, :should_be_a_tuple)
Finally, note Rebar v2 no longer works on Erlang/OTP 24+. Mix defaults to Rebar v3 since v1.4, so no changes should be necessary by the huge majority of developers. However, if you are explicitly setting manager: :rebar
in your dependency, you want to move to Rebar v3 by removing the :manager
option. Support for unsupported Rebar versions will be removed from Mix in the future.
Stepped ranges
Elixir has support for ranges from before its v1.0 release. Ranges support only integers and are inclusive, using the mathematic notation a..b
. Ranges in Elixir are either increasing 1..10
or decreasing 10..1
and the direction of the range was always inferred from the first and last positions. Ranges are always lazy as its values are emitted as they are enumerated rather than being computed upfront.
Unfortunately, due to this inference, it is not possible to have empty ranges. For example, if you want to create a list of n
elements, you cannot express it with a range from 1..n
, as 1..0
(for n=0
) is a decreasing range with two elements.
Elixir v1.12 supports stepped ranges via the first..last//step
notation. For example: 1..10//2
will emit the numbers 1
, 3
, 5
, 7
, and 9
. You can consider the //
operator as an equivalent to "range division", as it effectively divides the number of elements in the range by step
, rounding up on inexact scenarios. Steps can be either positive (increasing ranges) or negative (decreasing ranges). Stepped ranges bring more expressive power to Elixir ranges and they elegantly solve the empty range problem, as they allow the direction of the steps to be explicitly declared instead of inferred.
As of Elixir v1.12, implicitly decreasing ranges are soft-deprecated and warnings will be emitted in future Elixir versions based on our deprecation policy.
Additional functions
Elixir v1.12 has the additional of many functions across the standard library. The Enum
module received additions such as Enum.count_until/2
, Enum.product/1
, Enum.zip_with/2
, and more. The Integer
module now includes Integer.pow/2
and Integer.extended_gcd/2
. Finally, the Kernel
module got two new functions, Kernel.then/2
and Kernel.tap/2
, which are specially useful in |>
pipelines.
v1.12.0
1. Enhancements
EEx
- [EEx.Engine] Add
EEx.Engine.handle_text/3
callback that receives text metadata - [EEx.Engine] Emit warnings for unused "do" expression in EEx
Elixir
- [Code] Add
Code.cursor_context/2
to return the context of a code snippet - [Code] Do not add newlines around interpolation on code formatting. Note this means formatted code that has interpolation after the line length on Elixir v1.12 won't be considered as formatted on earlier Elixir versions
- [Code] Do not add brackets when keywords is used in the access syntax
- [Calendar] Support basic datetime format in
Calendar.ISO
parsing functions - [Code] Improve evaluation performance on systems running on Erlang/OTP 24+
- [Date] Support steps via
Date.range/3
- [DateTime] Add
offset
toDateTime.to_iso8601/2
(nowto_iso8601/3
) - [Enum] Add
Enum.count_until/2
andEnum.count_until/3
- [Enum] Add
Enum.product/1
- [Enum] Add
Enum.zip_with/2
,Enum.zip_with/3
,Enum.zip_reduce/3
, andEnum.zip_reduce/4
- [Enum] Add support for functions as the second argument of
Enum.with_index/2
- [Exception] Show
error_info
data for exceptions coming from Erlang - [Float] Add
Float.pow/2
- [Integer] Add
Integer.pow/2
andInteger.extended_gcd/2
- [IO] Add
IO.stream/0
andIO.binstream/0
which default to STDIO with line orientation - [List] Add default value for
List.first/1
andList.last/1
- [Kernel] Add
first..last//step
as support for stepped ranges - [Kernel] Also warn for literal structs on
min/2
andmax/2
- [Kernel] Add
Kernel.tap/2
andKernel.then/2
- [Kernel] Do not add runtime dependencies to remotes in typespecs
- [Kernel] When there is an unused variable warning and there is a variable with the same name previously defined, suggest the user may have wanted to use the pin operator
- [Kernel] Improve error messages on invalid character right after a number
- [Kernel] Show removal and deprecated tips from Erlang/OTP
- [Macro] Add export dependencies on
Macro.struct!/2
- [Macro] Support
:newline
to customize newlines escaping inMacro.unescape_string/2
- [Module] Raise on invalid
@dialyzer
attributes - [Module] Add
Module.get_definition/2
andModule.delete_definition/2
- [Module] Allow
@on_load
to be a private function - [Module] Validate
@dialyzer
related module attributes - [Module] Add
Module.reserved_attributes/0
to list all reserved attributes by the language - [Range] Add
Range.new/3
andRange.size/1
- [Regex] Add offset option to
Regex.scan/3
andRegex.run/3
- [Registry] Support
:compression
onRegistry
tables - [Registry] Support
Registry.values/3
for reading values under a given key-pid pair - [Stream] Add
Stream.zip_with/2
andStream.zip_with/3
- [String] Add
:turkic
mode option to String case functions - [String] Update to Unicode 13.0
- [System] Add
System.trap_signal/3
andSystem.untrap_signal/2
- [System] Add
System.shell/2
to invoke a command that is interpreted by the shell - [Tuple] Add
Tuple.sum/1
andTuple.product/1
- [URI] Support RFC3986 compliant encoding and decoding of queries via the
:rfc3986
option
ExUnit
- [ExUnit] Intercept SIGQUIT (via Ctrl+\) and show a list of all aborted tests as well as intermediate test results
- [ExUnit] Interpolate module attributes in match assertions diffs
- [ExUnit] Print how much time is spent on
async
vssync
tests - [ExUnit] Improve error messages for doctests
- [ExUnit] Compile doctests faster (often by two times)
- [ExUnit] Add
ExUnit.async_run/0
andExUnit.await_run/1
IEx
- [IEx] Make IEx' parser configurable to allow special commands
- [IEx] Show function signature when pressing tab after the opening parens of a function
- [IEx] If an IEx expression starts with a binary operator, such as
|>
, automatically pipe in the result of the last expression
Mix
- [Mix] Add
Mix.install/2
for dynamically installing a list of dependencies - [Mix] Support
:exit_code
option inMix.raise/2
- [Mix] Discard
MIX_ENV
andMIX_TARGET
values if they are empty strings - [Mix] Print the time taken to execute a task with on
MIX_DEBUG=1
- [mix compile.erlang] Compile multiple files in parallel
- [mix escript.build] Deep merge configuration and ensure argv is set when executing
config/runtime.exs
- [mix release] Add
RELEASE_PROG
to releases with the name of the executable starting the release - [mix release] Support
remote.vm.args
to customize how the connecting VM boots - [mix test] Run all available tests if there are no pending
--failed
tests. This provides a better workflow as you no longer need to toggle the--failed
flag between runs
2. Bug fixes
Elixir
- [CLI] Ensure
-e ""
(with an empty string) parses correctly on Windows - [Inspect] Do not override user supplied
:limit
option for derived implementations - [Kernel] Allow heredoc inside a heredoc interpolation
- [Kernel] Preserve CRLF on heredocs
- [Kernel] Public functions without documentation now appear as an empty map on
Code.fetch_docs/1
, unless they start with underscore, where they remain as:none
. This aligns Elixir's implementation with EEP48 - [Kernel] Do not crash when complex literals (binaries and maps) are used in guards
- [Kernel] Properly parse keywords (such as
end
) followed by the::
operator - [Kernel] Do not ignore unimplemented signatures from generated functions
- [Kernel] Improve error message when an expression follows a keyword list without brackets
- [Macro]
Macro.decompose_call/1
now also consider tuples with more than 2 elements to not be valid calls - [Macro] Fix
Macro.to_string/1
double-escaping of escape characters in sigils - [Macro] Fix
Macro.underscore/1
on digits preceded by capitals: "FOO10" now becomes "foo10" instead of "fo_o10" - [Macro] Preserve underscores between digits on
Macro.underscore/1
- [OptionParser] Properly parse when numbers follow-up aliases, for example,
-ab3
is now parsed as-a -b 3
- [Path] Fix
Path.relative_to/2
when referencing self - [Path] Do not crash when a volume is given to
Path.absname/1
, such as "c:" - [Task] Ensure
Task.async_stream/2
withordered: false
discard results as they are emitted, instead of needlessly accumulating inside the stream manager - [Task] Raise if
:max_concurrency
is set to 0 on streaming operations - [URI] Do not discard empty paths on
URI.merge/2
ExUnit
- [ExUnit.Case] Make
@tag tmp_dir
an absolute directory, avoiding inconsistencies if the test changes the current working directory - [ExUnit.Diff] Fix cases where the diffing algorithm would fail to print a pattern correct
IEx
- [IEx] Fix auto-completion inside remote shells
Mix
- [mix app.config] Do not emit false positive warnings when configured dependencies that have
runtime: false
set - [mix compile.elixir] Ensure that a manifest is generated even with no source code
- [mix compile.elixir] Make sure export dependencies trigger recompilation when the dependency is removed as well as when the whole file is removed
- [mix compile.elixir] Do not emit false positive warnings when a path dependency adds a module that is then used by the current application in the same
mix compile
cycle - [mix test] Ensure protocols within the current project are consolidated when
--cover
is given - [mix release] Improve compliance of release scripts with stripped down Linux installations
- [mix release] Preserve file mode when copying non-beam ebin files
- [mix xref] Ensure args are passed to the underlying
mix compile
call
3. Soft-deprecations (no warnings emitted)
Elixir
- [Kernel] Using
first..last
to match on ranges is soft-deprecated and will warn on future Elixir versions. Usefirst..last//step
instead - [Kernel] Using
first..last
to create decreasing ranges is soft-deprecated and will warn on future versions. Usefirst..last//-1
instead
4. Hard-deprecations
EEx
- [EEx.Engine]
use EEx.Engine
is deprecated in favor of explicit delegation
Elixir
- [Kernel] The binary operator
^^^
is deprecated. If you are usingBitwise.^^^/2
, useBitwise.bxor/2
instead - [Kernel] Deprecate
@foo()
in favor of@foo
- [System] Deprecate
System.stacktrace/0
(it was already deprecated outside of catch/rescue and now it is deprecated everywhere)
Mix
- [mix compile] The
:xref
compiler is deprecated and it has no effect. Please remove it from your mix.exs file.
v1.11
The CHANGELOG for v1.11 releases can be found in the v1.11 branch.