v1.6.0

Official announcement: https://elixir-lang.org/blog/2018/01/17/elixir-v1-6-0-released/

1. Enhancements

EEx

• [EEx] Allow markers / and | to be used in a custom EEx engine

Elixir

• [Calendar] Add truncate to Time, DateTime and NaiveDateTime to facilitate microsecond precision pruning
• [Code] Add format_string!/2 and format_file!/2 for automatic code formatting
• [Code] Support column annotations in quoted expressions with columns: true in Code.string_to_quoted/2
• [DynamicSupervisor] Add DynamicSupervisor designed to manage children that are added and removed dynamically
• [Exception] Make Exception.blame/3 extensible by adding an optional blame/2 callback to exceptions
• [Exception] Improve the printing of guards on blamed exceptions
• [Enumerable] Add Enumerable.slice/1 and optimize many Enum operations with the new protocol. This allows data-structures with index-based random access to provide a non-linear implementation
• [Inspect] Show UTF-8 BOM on inspected strings
• [Inspect.Algebra] Add :strict and :flex breaks - this gives more control over the document fitting
• [Inspect.Algebra] Allow a group to inherit the parent group break
• [Inspect.Algebra] Add force_unfit/1 and next_break_fits/2 which give more control over document fitting
• [Inspect.Algebra] Add collapse_lines/1 for collapsing multiple lines to a maximum value
• [Inspect.Algebra] Allow nest/2 to be :reset or be set to the current :cursor position
• [Kernel] Prefix variables with V when emitting Erlang code. This improves the integration with tools such as Erlang code formatters and the GUI debugger
• [Kernel] Warn on the use of length(x) == 0 in guards
• [Kernel] Warn if catch comes before rescue in try
• [Kernel] Warn if heredoc is outdented compared to its closing quotes
• [Kernel] Add defguard/1 and defguardp/1 to make it easier to build guard-safe macros
• [Kernel.ParallelCompiler] Add compile/2, compile_to_path/3 and require/2 which provide detailed information about warnings and errors
• [Kernel.SpecialForms] Support the uniq: true flag in for comprehensions
• [Module] Introduce @deprecated and @since attributes
• [List] Rearrange equals and inserts for shorter diff scripts in List.myers_difference/2
• [Record] Allow :macros and :includes to be given to Record.extract/2
• [Stream] Add Stream.intersperse/2
• [String] Update to Unicode 10
• [String] Allow passing empty string match to String.replace/4
• [String] Support context and language sensitive operations in String.upcase/2 and String.downcase/2. Currently only the :greek context is supported
• [String] Support :ascii conversion in String.upcase/2 and String.downcase/2
• [Time] Add Time.add/3

ExUnit

• [ExUnit.Assertions] Perform inclusive checks in assert_in_delta
• [ExUnit.Callbacks] Add ExUnit.Callbacks.start_supervised!/2
• [ExUnit.Case] Generate a random seed per test based on the test suite seed

IEx

• [IEx.Autocomplete] Provide contextual autocompletion: t Enum. will autocomplete types, b Enum will autocomplete callbacks
• [IEx.CLI] Provide hints for developers when a bad host name is given to --remsh
• [IEx.Helpers] Automatically include specs when showing documentation for functions/macros
• [IEx.Helpers] Improve formatting of behaviours and typespecs by using the formatter
• [IEx.Helpers] Allow pattern matching and guard expressions when on IEx.break!

Logger

• [Logger] Add :discard_threshold to Logger to help with message queue overflow

Mix

• [mix app.start] Add --preload-modules to mix app.start
• [mix archive.build] Allow mix archive.build to bundle dot files via an option
• [mix compile] Define a behavior for Mix compiler tasks and return diagnostics from compiler tasks
• [mix compile] Track struct dependencies between files and recompile them only if the struct changes
• [mix deps] Support :system_env option when specifying dependencies
• [mix format] Add a mix format task that formats the given files (or the files specified in a .formatter.exs file)
• [mix profile.eprof] Add a new task for time-based profiling with eprof
• [mix test] Run all functions in a describe block by giving the file:line the describe block starts
• [mix test] Report the top N slowest tests with the --slowest N flag
• [mix test] Report the number of doctests and tests separately
• [mix xref] Support --include-siblings in reports for umbrella support
• [mix xref] Add mix xref graph --format stats
• [mix xref] Add --only-nodes and --label filters to mix xref graph
• [mix xref] Add mix xref deprecated that shows the callsite of deprecated functions

2. Bug fixes

Elixir

• [CLI] Support path with spaces as argument to elixir.bat
• [Inspect] Properly handle minus signal for non-decimal negative integers
• [Integer] Do not raise on non-integer values in is_odd/is_even
• [Kernel] Solve a precedence issue between & and |, such as [&Foo.bar/1 | &Baz.bat/2]
• [Kernel] Do not load dynamic Elixir modules as :in_memory as this value is not officially supported by the code server. Instead, use an empty list, which is the same value used by Erlang.
• [Kernel] Validate variable struct name is atom when used in pattern matching
• [Kernel] No longer generate documentation for defdelegate functions automatically to avoid overriding previously specified @doc
• [Macro] Fix Macro.to_string/2 for tuple calls, such as alias Foo.{Bar, Baz}
• [MapSet] Return valid MapSet when unioning a legacy MapSet
• [Regex] Return a leading empty space when splitting on empty pattern. This makes the split operation consistent with the other operations in the Regex module
• [Stream] Ensure Stream.chunk_while/4 does not emit more elements than necessary when halted
• [String] Return a leading empty space when splitting on empty string. This makes the split operation consistent with the other operations in the String module
• [URI] Preserve empty fragments in URI.parse/1

Mix

• [mix app.start] Improve the quality of reports if app fails to boot
• [mix cmd] Allow mix cmd to be invoked multiple times without marking it as executed
• [mix deps] Ensure optional dependencies in umbrella applications are loaded
• [mix deps.update] Ensure transitive new non-Hex dependencies are also fetched when a repo is updated
• [mix xref] Take compile dependencies with higher priority than runtime ones when building a graph
• [mix xref] Handle external files for xref callers and warnings

3. Soft deprecations (no warnings emitted)

Elixir

• [GenServer] Warn if init/1 is not defined in GenServer. This brings GenServer closer to the implementation in OTP and aligns all behaviours to require the init/1 callback
• [Inspect.Algebra] surround/3 and surround_many/6 are deprecated in favor of container_doc/6
• [Kernel] Specifying map types with variable keys without defining the type as required/optional is deprecated
• [Kernel.ParallelCompiler] files/2 and files_to_path/3 are deprecated in favor of compile/2 and compile_to_path/3
• [Kernel.ParallelRequire] files/2 is deprecated in favor of Kernel.ParallelCompiler.require/2
• [Supervisor] The :simple_one_for_one strategy is deprecated in favor of DynamicSupervisor
• [Supervisor] Passing a list of args to Supervisor.start_child/2 is deprecated in favor of DynamicSupervisor
• [Task.Supervisor] Passing :restart and :shutdown to Task.Supervisor.start_link/2 is deprecated (it should be passed on start child instead)

ExUnit

• [ExUnit.Formatter] :case_started and :case_finished events are deprecated in favor of :module_started and :module_finished

Mix

• [Mix.Compilers.Erlang] Returning {:ok, val} | :error from custom Erlang compilers is deprecated in favor of {:ok, val, warnings} | {:error, errors, warnings}

4. Deprecations

Elixir

• [Enum] Enum.partition/2 is deprecated in favor of Enum.split_with/2
• [Keyword] Keyword.replace/3 is deprecated in favor of Keyword.fetch/2 and Keyword.put/3
• [Map] Map.replace/3 is deprecated in favor of Map.fetch/2 and Map.put/3
• [Macro] Macro.unescape_tokens/1 and Macro.unescape_tokens/2 are deprecated in favor of Enum.map/2
• [Range] Deprecate Range.range?/1 in favor of pattern matching on _ .. _