View Source Changelog for Elixir v1.16

Code snippets in diagnostics

Elixir v1.15 introduced a new compiler diagnostic format and the ability to print multiple error diagnostics per compilation (in addition to multiple warnings).

With Elixir v1.16, we also include code snippets in exceptions and diagnostics raised by the compiler. For example, a syntax error now includes a pointer to where the error happened:

** (SyntaxError) invalid syntax found on lib/my_app.ex:1:17:
    error: syntax error before: '*'
    │
  1 │ [1, 2, 3, 4, 5, *]
    │                 ^
    │
    └─ lib/my_app.ex:1:17

For mismatched delimiters, it now shows both delimiters:

** (MismatchedDelimiterError) mismatched delimiter found on lib/my_app.ex:1:18:
    error: unexpected token: )
    │
  1 │ [1, 2, 3, 4, 5, 6)
    │ │                └ mismatched closing delimiter (expected "]")
    │ └ unclosed delimiter
    │
    └─ lib/my_app.ex:1:18

For unclosed delimiters, it now shows where the unclosed delimiter starts:

** (TokenMissingError) token missing on lib/my_app:8:23:
    error: missing terminator: )
    │
  1 │ my_numbers = (1, 2, 3, 4, 5, 6
    │              └ unclosed delimiter
 ...
  8 │ IO.inspect(my_numbers)
    │                       └ missing closing delimiter (expected ")")
    │
    └─ lib/my_app:8:23

Errors and warnings diagnostics also include code snippets. When possible, we will show precise spans, such as on undefined variables:

  error: undefined variable "unknown_var"
  │
5 │     a - unknown_var
  │         ^^^^^^^^^^^
  │
  └─ lib/sample.ex:5:9: Sample.foo/1

Otherwise the whole line is underlined:

error: function names should start with lowercase characters or underscore, invalid name CamelCase
  │
3 │   def CamelCase do
  │   ^^^^^^^^^^^^^^^^
  │
  └─ lib/sample.ex:3

A huge thank you to Vinícius Müller for working on the new diagnostics.

Revamped documentation

Elixir's Getting Started guides have been made part of the Elixir repository and incorporated into ExDoc. This was an opportunity to revisit and unify all official guides and references.

We have also incorporated and extended the work on Understanding Code Smells in Elixir Functional Language, by Lucas Vegi and Marco Tulio Valente, from ASERG/DCC/UFMG, into the official document in the form of anti-patterns. The anti-patterns are divided into four categories: code-related, design-related, process-related, and meta-programming. Our goal is to give all developers examples of potential anti-patterns, with context and examples on how to improve their codebases.

Another ExDoc feature we have incorporated in this release is the addition of cheatsheets, starting with a cheatsheet for the Enum module. If you would like to contribute future cheatsheets to Elixir itself, feel free to start a discussion with an issue.

Finally, we have started enriching our documentation with Mermaid.js diagrams. You can find examples in the GenServer and Supervisor docs.

v1.16.0 (2023-12-22)

1. Enhancements

EEx

[EEx] Include relative file information in diagnostics

Elixir

[Code] Add :emit_warnings for Code.string_to_quoted/2
[Code] Automatically include columns in parsing options
[Code] Introduce MismatchedDelimiterError for handling mismatched delimiter exceptions
[Code.Fragment] Handle anonymous calls in fragments
[Code.Formatter] Trim trailing whitespace on heredocs with \r\n
[File] Add :offset option to File.stream!/2
[Kernel] Auto infer size of matched variable in bitstrings
[Kernel] Preserve column information when translating typespecs
[Kernel] Suggest module names based on suffix and casing errors when the module does not exist in UndefinedFunctionError
[Kernel.ParallelCompiler] Introduce Kernel.ParallelCompiler.pmap/2 to compile multiple additional entries in parallel
[Kernel.SpecialForms] Warn if True/False/Nil are used as aliases and there is no such alias
[Macro] Add Macro.compile_apply/4
[Module] Add support for @nifs annotation from Erlang/OTP 25
[Module] Add support for missing @dialyzer configuration
[String] Update to Unicode 15.1.0
[String] Add String.replace_invalid/2
[Task] Add :limit option to Task.yield_many/2

Logger

[Logger] Add Logger.levels/0

Mix

[mix] Add MIX_PROFILE to profile a list of comma separated tasks
[mix archive.install] Support --sparse option
[mix compile.app] Warn if both :applications and :extra_applications are used
[mix compile.elixir] Pass original exception down to diagnostic :details when possible
[mix compile.elixir] Optimize scenario where there are thousands of files in lib/ and one of them is changed
[mix deps.clean] Emit a warning instead of crashing when a dependency cannot be removed
[mix escript.install] Support --sparse option
[mix release] Include include/ directory in releases
[mix test] Allow testing multiple file:line at once, such as mix test test/foo_test.exs:13 test/bar_test.exs:27

2. Bug fixes

Elixir

[Code] Keep quotes for atom keys in formatter
[Code.Fragment] Fix crash in Code.Fragment.surround_context/2 when matching on ->
[IO] Raise when using IO.binwrite/2 on terminated device (mirroring IO.write/2)
[Kernel] Do not expand aliases recursively (the alias stored in Macro.Env is already expanded)
[Kernel] Ensure dbg module is a compile-time dependency
[Kernel] Warn when a private function or macro uses unquote/1 and the function/macro itself is unused
[Kernel] Re-enabled compiler optimizations for top level functions in scripts (disabled in v1.14.0 but shouldn't impact most programs)
[Kernel] Do not define an alias for nested modules starting with Elixir. in their definition
[Kernel.ParallelCompiler] Consider a module has been defined in @after_compile callbacks to avoid deadlocks
[Macro] Address exception on Macro.to_string/1 for certain ASTs
[Path] Lazily evaluate File.cwd!/0 in Path.expand/1 and Path.absname/1
[Path] Ensure Path.relative_to/2 returns a relative path when the given argument does not share a common prefix with cwd

ExUnit

[ExUnit] Raise on incorrectly dedented doctests

IEx

[IEx.Pry] Fix prying functions with only literals in their body

Mix

[mix archive.install] Restore code paths after mix archive.install
[mix compile] Ensure files with duplicate modules are recompiled whenever any of the files change
[mix compile] Update Mix compiler diagnostics documentation and typespecs to match the Elixir compiler behaviour where both lines and columns start from one (before it inaccurately said that columns started from zero)
[mix escript.install] Restore code paths after mix escript.install

3. Soft deprecations (no warnings emitted)

Elixir

[File] Deprecate File.stream!(file, options, line_or_bytes) in favor of keeping the options as last argument, as in File.stream!(file, line_or_bytes, options)
[Kernel.ParallelCompiler] Deprecate Kernel.ParallelCompiler.async/1 in favor of Kernel.ParallelCompiler.pmap/2
[Path] Deprecate Path.safe_relative_to/2 in favor of Path.safe_relative/2

Mix

[mix compile] Returning a four-element tuple as a position in Mix.Task.Compiler.Diagnostic

4. Hard deprecations

Elixir

[Date] Deprecate inferring a range with negative step, call Date.range/3 with a negative step instead
[Enum] Deprecate passing a range with negative step on Enum.slice/2, give first..last//1 instead
[Kernel] ~R/.../ is deprecated in favor of ~r/.../. This is because ~R/.../ still allowed escape codes, which did not fit the definition of uppercase sigils
[String] Deprecate passing a range with negative step on String.slice/2, give first..last//1 instead

ExUnit

[ExUnit.Formatter] Deprecate format_time/2, use format_times/1 instead

Mix

[mix compile.leex] Require :leex to be added as a compiler to run the leex compiler
[mix compile.yecc] Require :yecc to be added as a compiler to run the yecc compiler

v1.15

The CHANGELOG for v1.15 releases can be found in the v1.15 branch.

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