CHANGELOG.md

Changelog for Elixir v1.1

v1.1 brings enhancements, bug fixes, performance improvements and more into Elixir.

Elixir v1.1 supports both Erlang 17 and Erlang 18 and, for this reason, it does not introduce any feature that is specific to Erlang 18. Such will be tackled on the follow up Elixir v1.2 release.

On the enhancements side, the most notable changes are the new functions added to Enum, Dict and Task modules, and a new datatype called MapSet. MapSet implements the Set API on top of a map and, for Elixir v1.1, it is useful for holding only dozens of entries. Future Elixir versions, however, will be able to rely on MapSet from dozens of keys up to millions, with better performance than HashSet.

On the deprecation side, this release includes one major deprecation and some soft deprecations.

The major deprecation relates to the Access protocol. Due to performance issues, the access syntax opts[key] will no longer be powered by the Access protocol, instead, it will use the Dict module. Therefore this release will emit warnings if you attempt to implement the Access protocol. Note the Access module and the opts[key] syntax are not affected and they are not deprecated, only the underlying protocol dispatch.

The soft deprecations are minor and they won't emit warnings. It simply means the documentation has been updated to mention the new best practices. Warnings will be emitted in the future though (when they are promoted to deprecations).

On the tooling side, ExUnit got the ability to skip tests and a couple new configuration options. Mix got improved warnings and error messages, faster compilation times and the brand new mix profile.fprof task.

Finally, Mix now ships with local.public_keys to safely manage the installation of Hex and Rebar alongside the ability to checksum archive installs. By default, Elixir will always ship with a valid public key and this feature should work transparently for users.

Note: Erlang 17.1 contains a regression in its wildcard implementation that causes tools like rebar to fail. If you have a project with rebar dependencies and is using Erlang 17.1, remember to update to at least Erlang 17.3.

v1.1.0-dev

1. Enhancements

Elixir

• [Application] Add Application.fetch_env!/2, Application.loaded_applications/0 and Application.started_applications/0
• [CLI] Add support for --werl in Windows bash-like shells
• [Dict] Add Dict.get_and_update/3 which behaves similar to the now deprecated Access protocol
• [Dict] Add Dict.get_lazy/3, Dict.pop_lazy/3 and Dict.put_new_lazy/3
• [Enum] Add Enum.random/1, Enum.take_random/2, Enum.min_max/1, Enum.min_max_by/2, Enum.reverse_slice/3, Enum.dedup/1 and Enum.dedup_by/2
• [Enum] Inline common map usage in Enum functions for performance
• [File] Add File.lstat/1 and File.lstat/1 that works like File.stat/1 but is able to return symlink information (i.e. it does not traverse symlinks)
• [Integer] Add Integer.digits/2 and Integer.undigits/2
• [Inspect] Add the :safe option to inspect/2 and make it safe by default, meaning failures while inspecting won't trigger other failures. Instead, it will be wrapped in an exception which is properly formatted
• [IO] Support fenced code blocks on IO.ANSI.Docs
• [GenServer] Add GenServer.whereis/1 that expands GenServer dispatches into a proper pid
• [Kernel] No longer include :crypto and :syntax_tools as dependencies. The former is only needed if you have encrypted debug info (therefore you can add :crypto as a dependency manually) and the latter is no longer used
• [Kernel] Raise when var.Alias syntax is used and it does not expand to an atom at compile time (previously it emitted warnings)
• [Kernel] Improve generation of argument names for function signatures
• [Kernel] ::/2 is now a special form
• [Kernel] Warn when a variable with underscore is used
• [Kernel] Allow underscores in binary, octal and hex literals
• [Kernel] Warn when module attributes, variables, strings and numbers are used in code but the expression has no effect
• [Kernel] Support \uXXXX and \u{X*} in strings and char lists to map to Unicode codepoints
• [List] Add List.keytake/3
• [Module] Improve name inference for function signatures in documentation metadata
• [Process] Add Process.hibernate/3
• [Set] Introduce MapSet data type. This new data type uses maps behind the scenes and is useful for storing a dozens of items in Erlang 17. In future versions when maps efficiently support large collections, it is meant to be the main Set abstraction in Elixir
• [Stream] Add Stream.dedup/1 and Stream.dedup_by/2
• [String] Support calculation of the jaro distance between strings (usually names) via String.jaro_distance/2. This is used by Mix to support "Did you mean?" feature when a task does not exist
• [String] Add String.splitter/3 that splits strings as a stream
• [StringIO] StringIO.flush/1 was added to flush the output of a StringIO device
• [Task] Introduce Task.yield/2 and Task.shutdown/2 to check if a task is still executing and shutdown otherwise
• [Tuple] Add Tuple.append/2
• [URI] Default ports were added for "ws" and "wss" schemas
• [URI] Add URI.to_string/1

EEx

• [EEx] Add :trim option to EEx that automatically trims the left side of <% and right side %> if only spaces and new lines preceed/follow them

ExUnit

• [ExUnit] Add number of skipped tests to ExUnit output
• [ExUnit] Make timeout configurable for the whole test suite via the :timeout configuration
• [ExUnit] Allow moduledoc to be filtered/skipped in doctests
• [ExUnit] Provide built-in log capturing functionality
• [ExUnit] Allow assert_receive_timeout and refute_receive_timeout to be configured in the ExUnit application
• [ExUnit] Allow tests to be skipped with @tag :skip or @tag skip: "reason"

IEx

• [IEx] Support IEx.pry with --remsh for remote debugging
• [IEx] Add b/1 helper that shows documentation for behaviour modules and its callback functions
• [IEx] Provide tab completion for aliases and allow aliases like Foo.Bar.Baz to autocomplete even if Foo.Bar is not defined
• [IEx] Provide a pid/3 helper for buildings pids from numbers

Logger

• [Logger] Support printing pids and refs in Logger metadata
• [Logger] Allow logger metadata to be removed from pdict by setting it to nil
• [Logger] Add application configuration translator_inspect_opts for logger to customize how state and message are formatted when translating OTP errors and reports
• [Logger] Automatically include the current application in metadata when compiled via Mix

Mix

• [Mix] Check Elixir version right after archive installation and provide feedback if there is a mismatch
• [Mix] Allow rebar dependencies with mix.exs to be compiled with Mix
• [Mix] Allow rebar dependencies to be specified via :path
• [Mix] Also consider subdirectories in config directory for Mix.Project.config_files/0
• [Mix] Allow dynamic configuration in Mix projects by storing config in an agent
• [Mix] Support rebar3 style git refs in rebar.config files
• [Mix] Only recompile compile time dependencies in mix projects. This should considerably speed up recompilation times in Elixir projects
• [Mix] Warn when configuring an application that is not available
• [Mix] Add mix profile.fprof for easy code profiling
• [Mix] Abort when dependencies have conflicting :only definitions
• [Mix] Fully recompile projects if Elixir or SCM changes
• [Mix] Allow checksum to be checked on archive install via --sha512 option
• [Mix] Add mix local.public_keys to safely manage installation of Hex and Rebar dependencies

2. Bug fixes

Elixir

• [CLI] Ensure Logger messages are flushed when executing commands
• [Code] :delegate_locals_to failed to delegate to the chosen module in many situations and messed up stacktraces. This option has therefore been replaced by imports
• [Code] Store the documentation line in the metadata returned by Code.get_docs/2
• [Exception] Do not fail when calculating an exception message, even if the message is invalid
• [Kernel] Do not expand in/2 argument in module body
• [Kernel] Throw syntax error for undefind atom/alias syntax :foo.Bar
• [Kernel] Improve error message when we can't compile because the target directory is not writeable
• [Kernel] Allow capture of non-symbolic operators like &and/2, &not/1 and others
• [Kernel] Raise if heredoc terminal is accidentally found in the middle of a line without escaping
• [Module] Do not accept non-Elixir module names in Module.split/1
• [Protocol] Guarantee that derived protocols go through Any instead of Map
• [Range] Restrict ranges to integers to fix diverse bugs of values being included in the range when they should not (false positives)
• [Regex] Fix splitting of empty strings with regexes when trim is set to true. Now both String.split/3 and Regex.split/3 return an empty list when called with an empty string and trim is enabled
• [Regex] Fix Regex.replace/4 so it doesn't discard escape characters

EEx

• [EEx] Allow EEx interpolation to also apply inside quotations <%%= ... %>

ExUnit

• [ExUnit] Skipped tests now correctly count towards the total of tests in the result returned by ExUnit.run/0
• [ExUnit] Fix a bug where failures when inspecting data structure or retrieving error messages could bring the whole ExUnit runner down
• [ExUnit] Do not change the semantics of evaluated code with assert/refute. For example, from now on, assert nil = some_expr() will now raise as expected, as the expression still evaluates to a falsy value
• [ExUnit] Report proper line number for doctest failures

Logger

• [Logger] Include metadata in Logger.log/3, use Logger.bare_log/3 for runtime-only, with no metadata behaviour

Mix

• [Mix] Use the safer https protocol instead of git for :github dependencies
• [Mix] Ensure automatic protocol consolidation via :consolidate_protocols is triggered in umbrella apps
• [Mix] Do not raise if wildcard given to import_config does not match any file
• [Mix] Applications with :build_embedded set to true require explicit compilation step
• [Mix] Also remove consolidated protocols on mix clean

3. Soft deprecations (no warnings emitted)

Elixir

• [Behaviour] The module Behaviour is deprecated. Instead of defcallback, one can simply use @callback. Instead of defmacrocallback, one can simply use @macrocallback
• [Enum] Enum.uniq/2 is deprecated in favor of Enum.uniq_by/2
• [Kernel] \x inside strings and charlists is deprecated in favor of \uXXXX and \u{X*}. The values emitted by \x are unfortunately wrong (they should be bytes but currently it emits codepoints). \u is meant to correctly map to codepoints and \x will be fixed in the future to map to bytes
• [Regex] Ungreedy option r is deprecated in favor of U (which is standard in regular expressions in other languages)

4. Deprecations

Elixir

• [Access] Implementing the Access protocol is deprecated. The Access protocol relies on the code server in development and test mode (when protocol consolidation is not applied) and it generated a bottleneck when working with multiple processes and the Access protocol was invoked hundreds of times (which is not uncommon). Note the Access module and the opts[key] syntax are not affected and they are not deprecated, only the underlying protocol dispatch
• [Kernel] ?\xHEX is deprecated in favor of 0xHEX. There is no situation where the former should be used in favor of the latter and the latter is always cleaner
• [Kernel] Giving as: true | false to alias/2 and require/2 have been deprecated (it was undocumented behaviour)
• [String] Passing an empty string to starts_with?, contains? and ends_with? had dubious behaviour and have been deprecated to help developers identify possible bugs in their source code