v1.18.0

Official announcement: https://elixir-lang.org/blog/2024/12/19/elixir-v1-18-0-released/

1. Enhancements

Elixir

• [CLI] Add experimental PowerShell scripts for elixir, elixirc, and mix on Windows. Those provide a safer entry point for running Elixir from other platforms
• [Calendar] Add Duration.to_string/1
• [Code] Support several migration options in Code.format_string!/2
• [Code] Add parenthesis around -- and --- in Code.format_string!/2 to make precedence clearer
• [Code] Include more metadata in Code.string_to_quoted/2 when token_metadata: true to help compute ranges from the AST
• [Code.Fragment] Have :capture_arg as its own entry in Code.Fragment.surround_context/2
• [Config] Add Config.read_config/1
• [Enumerable] Add Enum.product_by/2 and Enum.sum_by/2
• [Exception] Add MissingApplicationsError exception to denote missing applications
• [JSON] Add a new JSON module with encoding and decoding functionality
• [JSON] Implement JSON.Encoder for all Calendar types
• [Kernel] Update source code parsing to match UTS #55 latest recommendations. In particular, mixed script is allowed in identifiers as long as they are separate by underscores (_), such as http_сервер. Previously allowed highly restrictive identifiers, which mixed Latin and other scripts, such as the japanese word for t-shirt, Tシャツ, now require the underscore as well
• [Kernel] Warn on bidirectional confusability in identifiers
• [Kernel] Verify the type of the binary generators
• [Kernel] Track the type of tuples in patterns and inside elem/2
• [Kernel] Perform validation of root AST nodes in unquote and unquote_splicing to catch bugs earlier
• [Kernel] Add source, behaviour, and record information to Docs chunk metadata
• [Kernel] Support deterministic builds in tandem with Erlang by setting ERL_COMPILER_OPTIONS=deterministic. Keep in mind deterministic builds strip source and other compile time information, which may be relevant for programs
• [Kernel] Allow aliases and imports to be enabled conditionally in module body
• [List] Add List.ends_with?/2
• [Macro] Improve dbg handling of if/2, with/1 and of code blocks
• [Macro] Add Macro.struct_info!/2 to return struct information mirroring mod.__info__(:struct)
• [Registry] Add Registry.lock/3 for local locking
• [PartitionSupervisor] Add PartitionSupervisor.resize!/2 to resize the number of partitions in a supervisor (up to the limit it was started with)
• [Process] Handle arbitrarily high integer values in Process.sleep/1
• [Protocol] Add @undefined_impl_description to customize error message when an implementation is undefined
• [Protocol] Add __deriving__/1 as optional macro callback to Protocol, no longer requiring empty implementations
• [String] Inspect special whitespace and zero-width characters using their Unicode representation
• [String] Update Unicode to 16.0

ExUnit

• [ExUnit] Support parameterized tests on ExUnit.Case
• [ExUnit] Support test groups: tests in the same group never run concurrently
• [ExUnit.Case] Add test_pid as a tag

IEx

• [IEx] Add IEx.configure(auto_reload: true) to automatically pick up modules recompiled from other operating system processes
• [IEx] Add :dot_iex support to IEx.configure/1
• [IEx] Add report for normal/shutdown exits in IEx

Mix

• [mix compile] Ensure only a single operating system process can compile at a given time
• [mix deps.get] Ensure only a single operating system process can fetch deps at a given time
• [mix format] Add mix format --migrate to migrate from deprecated functionality
• [mix format] Add new options and metadata to improve formatting applying by editors and other environments
• [mix test] Taint failure manifest if requiring or compiling tests fail
• [Mix.Project] Add a :listeners configuration to listen to compilation events from the current and other operating system processes
• [Mix.Task.Compiler] Add API for fetching all persisted compiler diagnostics
• [Mix.Task.Compiler] Add API for fetching all compiler tasks

2. Bug fixes

Elixir

• [Code] Fix delimiter metadata for single quoted atoms and remote calls in Code.string_to_quoted/2
• [Code.Formatter] Fix formatter adding extra escapes to quoted remote calls
• [Code.Fragment] Properly handle keyword keys as their own entry
• [Inspect.Algebra] Ensure next_break_fits respects line_length
• [Kernel] Validate AST on unquote and unquote_splicing to provide better error reports instead of failing too late inside the compiler
• [Kernel] Avoid crashes when emitting diagnostics on code using \t for indentation
• [Module] Include module attribute line and name when tracing its aliases
• [Stream] Do not halt streams twice in Stream.transform/5
• [URI] Fix a bug when a schemaless URI is given to URI.merge/2

ExUnit

• [ExUnit.Assertions] Raise if guards are used in assert/1 with =
• [ExUnit.Assertions] Format inserted/deleted maps in list assertions

IEx

• [IEx.Helpers] IEx.Helpers.recompile/0 will reload modules changed by other operating system processes

Mix

• [mix compile] Ensure warnings from external resources are emitted with --all-warnings when files do not change
• [mix deps.compile] Fix escaping issues when invoking rebar3 in some cases
• [mix escript] Fix escript layout and support storing priv directories
• [mix release] Make .app files deterministic in releases
• [Mix.Shell] Fix Mix.Shell on Windows when outputting non UTF-8 characters

3. Soft deprecations (no warnings emitted)

Elixir

• [Inspect.Algebra] color/3 is deprecated in favor of color_doc/3
• [Inspect.Algebra] fold_doc/2 is deprecated in favor of fold/2
• [Kernel] Deprecate unless in favor of if. Use mix format --migrate to automate the migration
• [Macro] Macro.struct!/2 is deprecated in favor of Macro.struct_info!/2
• [Protocol] Defining __deriving__/3 inside the Any implementation is deprecated, derive it inside the protocol definition itself

4. Hard deprecations

EEx

• [EEx] <%# is deprecated in favor of <%!-- or <% #
• [EEx] c:EEx.handle_text/2 is deprecated in favor of c:EEx.handle_text/3

Elixir

• [Code] Setting :warnings_as_errors is deprecated via Code.put_compiler_option/2. This must not affect developers, as the :warnings_as_errors option is managed by Mix tasks, and not directly used via the Code module
• [Enumerable] Deprecate returning a two-arity function in Enumerable.slice/1
• [List] List.zip/1 is deprecated in favor of Enum.zip/1
• [Module] Deprecate Module.eval_quoted/3 in favor of Code.eval_quoted/3
• [Range] Deprecate inferring negative ranges on Range.new/2
• [Tuple] Tuple.append/2 is deprecated, use Tuple.insert_at/3 instead

Mix

• [mix cmd] Deprecate mix cmd --app APP in favor of mix do --app APP
• [mix compile] :warnings_as_errors configuration in :elixirc_options is deprecated. Instead pass the --warnings-as-errors flag to mix compile. Alternatively, you might alias the task: aliases: [compile: "compile --warnings-as-errors"]
• [mix test] :warnings_as_errors configuration in :test_elixirc_options is deprecated. Instead pass the --warnings-as-errors flag to mix test. Alternatively, you might alias the task: aliases: [test: "test --warnings-as-errors"]
• [Mix.Tasks.Compile] Deprecate compilers/0 in favor of Mix.Task.Compiler.compilers/0

v1.17

The CHANGELOG for v1.17 releases can be found in the v1.17 branch.