Changelog for Elixir v1.7

Elixir v1.7 is the last release to support Erlang/OTP 19. We recommend everyone to migrate to Erlang/OTP 20+.

Documentation metadata

Elixir v1.7 implements EEP 48. EEP 48 aims to bring documentation interoperability across all languages running on the Erlang VM. The documentation format proposed by EEP 48 also supports metadata, which is now fully exposed to Elixir developers:

@moduledoc "A brand new module"
@moduledoc authors: ["Jane", "Mary"], since: "1.4.0"

Passing metadata is supported on @doc, @moduledoc and @typedoc.

To access the new documentation format, developers should use Code.fetch_docs/1. The old documentation format is no longer available and the old Code.get_docs/2 function will return nil accordingly.

Tools like IEx and ExDoc have been updated to leverage the new format and show relevant metadata to users. While Elixir allows any metadata to be given, those tools currently exhibit only :deprecated and :since. Other keys may be shown in the future.

The `STACKTRACE` construct

Erlang/OTP 21.0 introduces a new way to retrieve the stacktrace that is lexically scoped and no longer relies on side-effects like System.stacktrace/0 does. Before one would write:

try do
  ... something that may fail ...
rescue
  e ->
    log(e, System.stacktrace())
    reraise(e, System.stacktrace())
end

In Elixir v1.7, this can be written as:

try do
  ... something that may fail ...
rescue
  e ->
    log(e, __STACKTRACE__)
    reraise(e, __STACKTRACE__)
end

This change may also yield performance improvements in the future, since the lexical scope allows us to track precisely when a stacktrace is used and we no longer need to keep references to stacktrace entries after the try construct finishes.

Other parts of the exception system have been improved. For example, more information is provided in certain occurrences of ArgumentError, ArithmeticError and KeyError messages.

Erlang/OTP logger integration

Erlang/OTP 21 includes a new :logger module. Elixir v1.7 fully integrates with the new :logger and leverages its metadata system. The Logger.Translator mechanism has also been improved to export metadata, allowing custom Logger backends to leverage information such as:

:crash_reason - a two-element tuple with the throw/error/exit reason as first argument and the stacktrace as second
:initial_call - the initial call that started the process
:registered_name - the process registered name as an atom

We recommend Elixir libraries that previously hooked into Erlang's :error_logger to hook into Logger instead, in order to support all current and future Erlang/OTP versions.

Other Logger improvements

Previously, Logger macros such as debug, info, and so on would always evaluate their arguments, even when nothing would be logged. From Elixir v1.7, the arguments are only evaluated when the message is logged.

The Logger configuration system also accepts a new option called :compile_time_purge_matching that allows you to remove log calls with specific compile-time metadata. For example, to remove all logger calls from application :foo with level lower than :info, as well as remove all logger calls from Bar.foo/3, you can use the following configuration:

config :logger,
  compile_time_purge_matching: [
    [application: :foo, level_lower_than: :info],
    [module: Bar, function: "foo/3"]
  ]

ExUnit improvements

ExUnit has also seen its own share of improvements. Assertions such as assert some_fun(arg1, arg2, arg3) will now include the value of each argument in the failure report:

  1) test function call arguments (TestOneOfEach)
     lib/ex_unit/examples/one_of_each.exs:157
     Expected truthy, got false
     code: assert some_vars(1 + 2, 3 + 4)
     arguments:

         # 1
         3

         # 2
         7

     stacktrace:
       lib/ex_unit/examples/one_of_each.exs:158: (test)

Furthermore, failures in doctests are now colored and diffed.

On the mix test side of things, there is a new --failed flag that runs all tests that failed the last time they ran. Finally, coverage reports generated with mix test --cover include a summary out of the box:

Generating cover results ...

Percentage | Module
-----------|--------------------------
   100.00% | Plug.Exception.Any
   100.00% | Plug.Adapters.Cowboy2.Stream
   100.00% | Collectable.Plug.Conn
   100.00% | Plug.Crypto.KeyGenerator
   100.00% | Plug.Parsers
   100.00% | Plug.Head
   100.00% | Plug.Router.Utils
   100.00% | Plug.RequestId
       ... | ...
-----------|--------------------------
    77.19% | Total

v1.7.4 (2018-10-24)

1. Enhancements

Elixir

[Kernel] Expand left..right at compile time in more cases, which leads to improved performance under different scenarios, especially on x in left..right expressions

Mix

[mix deps.loadpaths] Add --no-load-deps flag. This is useful for Rebar 3 compatibility

2. Bug fixes

Elixir

[Calendar] Fix for converting from negative iso days on New Year in a leap year
[Kernel] Ensure @spec, @callback, @type and friends can be read accordingly
[Module] Avoid warnings when using Module.eval_quoted in the middle of existing definitions

Mix

[mix archive.build] Unload previous archive versions before building
[mix format] Expand paths so mix format path\for\windows.ex works
[mix test] Ensure that --cover displays correct coverage in an umbrella app

v1.7.3 (2018-08-24)

1. Bug fixes

ExUnit

[ExUnit.Assertions] Do not attempt to expand try/1 as it is a special form

Mix

[mix compile.app] Do not include applications with runtime: false as a runtime dependency for applications coming from Hex

v1.7.2 (2018-08-05)

1. Bug fixes

Elixir

[DateTime] Take negative years into account in DateTime.from_iso8601/1
[Kernel] Do not emit warnings for repeated docs over different clauses due to false positives

Mix

[mix compile] Properly mark top-level dependencies as optional and as runtime. This fixes a bug where Mix attempted to start optional dependencies of a package when those optional dependencies were not available
[mix compile] Avoid deadlock when a config has a timestamp later than current time
[mix help] Show task and alias help when both are available
[mix test] Do not fail suite if there are no test files

v1.7.1 (2018-07-26)

1. Bug fixes

Elixir

[Calendar] Work-around a Dialyzer bug that causes it to loop for a long time, potentially indefinitely

v1.7.0 (2018-07-25)

1. Enhancements

Elixir

[Calendar.ISO] Support negative dates in Calendar.ISO
[Calendar] Add Calendar.months_in_year/1 callback
[Code] Add Code.compile_file/2 that compiles files without leaving footprints on the system
[Code] Add Code.purge_compiler_modules/0 that purges any compiler module left behind. This is useful for live systems dynamically compiling code
[Code] Add Code.fetch_docs/1 that returns docs in the EEP 48 format
[Date] Add Date.months_in_year/1 function
[DynamicSupervisor] Use the name of the DynamicSupervisor as the ID whenever possible
[Exception] Provide "did you mean" suggestions on KeyError
[Exception] Provide more information on ArithmeticError on Erlang/OTP 21+
[Function] Add Function module with capture/3, info/1 and info/2 functions
[GenServer] Support the new handle_continue/2 callback on Erlang/OTP 21+
[IO.ANSI] Add cursor movement to IO.ANSI
[Kernel] Support adding arbitrary documentation metadata by passing a keyword list to @doc, @moduledoc and @typedoc
[Kernel] Introduce __STACKTRACE__ to retrieve the current stacktrace inside catch/rescue (this will be a requirement for Erlang/OTP 21+)
[Kernel] Raise on unsafe variables in order to allow us to better track unused variables
[Kernel] Warn when using length to check if a list is not empty on guards
[Kernel] Add hints on mismatched do/end and others pairs
[Kernel] Warn when comparing structs using the >, <, >= and <= operators
[Kernel] Warn on unsupported nested comparisons such as x < y < z
[Kernel] Warn if redefining documentation across clauses of the same definition
[Kernel] Warn on unnecessary quotes around atoms, keywords and calls
[Macro] Add Macro.special_form?/2 and Macro.operator?/2 that returns true if the given name/arity is a special form or operator respectively
[Macro.Env] Add Macro.Env.vars/1 and Macro.Env.has_var?/2 that gives access to environment data without accessing private fields
[Regex] Include endianness in the regex version. This allows regexes to be recompiled when an archive is installed in a system with a different endianness
[Registry] Add Registry.count/1 and Registry.count_match/4
[String] Update to Unicode 11
[StringIO] Add StringIO.open/3
[System] Use ISO 8601 in System.build_info/0

ExUnit

[ExUnit.Assertion] Print the arguments in error reports when asserting on a function call. For example, if assert is_list(arg) fails, the argument will be shown in the report
[ExUnit.Diff] Improve diffing of lists when one list is a subset of the other
[ExUnit.DocTest] Show colored diffs on failed doctests
[ExUnit.Formatter] Excluded tests, via the --exclude and --only flags, are now shown as "Excluded" in reports. Tests skipped via @tag :skip are now exclusively shown as "Skipped" and in yellow

IEx

[IEx.Helpers] Add use_if_available/2
[IEx.Helpers] Allow force: true option in recompile/1
[IEx.Helpers] Add :allocators pane to runtime_info/1
[IEx.Helpers] Show documentation metadata in h/1 helpers

Logger

[Logger] Ensure nil metadata is always pruned
[Logger] Only evaluate Logger macro arguments when the message will be logged
[Logger] Add :compile_time_purge_matching to purge logger calls that match certain compile time metadata, such as module names and application names
[Logger] Log to :stderr if a backend fails and there are no other backends
[Logger] Allow translators to return custom metadata
[Logger] Return :crash_reason, :initial_call and :registered_name as metadata in crash reports coming from Erlang/OTP

Mix

[mix archive.install] Add support for the Hex organization via --organization
[mix archive.uninstall] Support --force flag
[mix compile] Improve support for external build tools such as rebar
[mix deps] Include override: true in rebar dependencies to make the behaviour closer to how rebar3 works (although diverged deps are still marked as diverged)
[mix escript.install] Add support for the Hex organization via --organization
[mix escript.uninstall] Support --force flag
[mix help] Also list aliases
[mix local] Use ipv6 with auto fallback to ipv4 when downloading data
[mix profile] Allow all profiling tasks to run programatically
[mix test] Add --failed option that only runs previously failed tests
[mix test] Print coverage summary by default when the --cover flag is given
[Mix.Project] Add Mix.Project.clear_deps_cache/0
[Mix.Project] Add Mix.Project.config_mtime/0 that caches the config mtime values to avoid filesystem access

2. Bug fixes

Elixir

[IO.ANSI.Docs] Fix table column alignment when converting docs to ANSI escapes
[Code] Ensure string_to_quoted returns error tuples instead of raising in certain constructs
[Code.Formatter] Consistently format keyword lists in function calls with and without parens
[Code.Formatter] Do not break after -> when there are only comments and one-line clauses
[File] Allow the :trim_bom option to be used with :encoding
[Kernel] Raise on unsafe variables as some of the code emitted with unsafe variables would not correctly propagate variables or would disable tail call optimization semantics
[Kernel] Do not crash on dynamic sizes in binary generators with collectable into in comprehensions
[Kernel] Do not crash on literals with non-unary size in binary generators with collectable into in comprehensions
[Task] Improve error reports and exit reasons for failed tasks on Erlang/OTP 20+

ExUnit

[ExUnit.Case] Raise proper error if @tag and @moduletag are used before use ExUnit.Case
[ExUnit.Case] Raise proper error if @describetag is used outside of describe/2 blocks
[ExUnit.DocTest] Emit proper assertion error on doctests with invalid UTF-8

Mix

[mix archive.install] Fetch optional dependencies when installing an archive from Git/Hex
[mix compile] Properly track config files in umbrella projects and recompile when any relevant umbrella configuration changes
[mix deps] Ensure the same dependency from different SCMs are tagged as diverged when those SCMs are remote and non-remote
[mix deps] Ensure we re-run dependency resolution when overriding a skipped dep in umbrella
[mix deps.compile] Perform clean builds for dependencies on outdated locks to avoid old modules from affecting future compilation
[mix escript.install] Fetch optional dependencies when installing an escript from Git/Hex

3. Soft-deprecations (no warnings emitted)

Elixir

[Code] Deprecate Code.load_file/2 in favor of Code.compile_file/2
[Code] Deprecate Code.loaded_files/0 in favor of Code.required_files/0
[Code] Deprecate Code.unload_files/1 in favor of Code.unrequire_files/1

Logger

[Logger] compile_time_purge_level is deprecated in favor of compile_time_purge_matching

4. Hard-deprecations

Elixir

[Code] Code.get_docs/2 is deprecated in favor of Code.fetch_docs/1
[Enum] Enum.chunk/2/3/4 is deprecated in favor of Enum.chunk_every/2/3/4 - notice chunk_every does not discard incomplete chunks by default
[GenServer] Warn if super is used in any of the GenServer callbacks
[Kernel] not left in right is ambiguous and is deprecated in favor of left not in right
[Kernel] Warn on confusing operator sequences, such as 1+++1 meaning 1 ++ +1 or ........ meaning ... .. ...
[OptionParser] Deprecate dynamic option parser mode that depended on atoms to be previously loaded and therefore behaved inconsistently
[Stream] Stream.chunk/2/3/4 is deprecated in favor of Stream.chunk_every/2/3/4 - notice chunk_every does not discard incomplete chunks by default

v1.6

The CHANGELOG for v1.6 releases can be found in the v1.6 branch.

Files

CHANGELOG.md

Latest commit

History

CHANGELOG.md

File metadata and controls

Changelog for Elixir v1.7

Documentation metadata

The __STACKTRACE__ construct

Erlang/OTP logger integration

Other Logger improvements

ExUnit improvements

v1.7.4 (2018-10-24)

1. Enhancements

Elixir

Mix

2. Bug fixes

Elixir

Mix

v1.7.3 (2018-08-24)

1. Bug fixes

ExUnit

Mix

v1.7.2 (2018-08-05)

1. Bug fixes

Elixir

Mix

v1.7.1 (2018-07-26)

1. Bug fixes

Elixir

v1.7.0 (2018-07-25)

1. Enhancements

Elixir

ExUnit

IEx

Logger

Mix

2. Bug fixes

Elixir

ExUnit

Mix

3. Soft-deprecations (no warnings emitted)

Elixir

Logger

4. Hard-deprecations

Elixir

v1.6

The `STACKTRACE` construct