OTP 28.0-rc1

Erlang/OTP 28.0-rc1 is the first release candidate of three before the OTP 28.0 release.

The intention with this release is to get feedback from our users. All feedback is welcome, even if it is only to say that it works for you. We encourage users to try it out and give us feedback either by creating an issue at https://github.com/erlang/otp/issues or by posting to Erlang Forums.

All artifacts for the release can be downloaded from the Erlang/OTP Github release and you can view the new documentation at https://erlang.org/documentation/doc-16.0-rc1/doc.

You can also install the latest release using kerl like this:

kerl build 28.0-rc1 28.0-rc1.

Starting with this release, a source Software Bill of Materials (SBOM) will describe the release on the Github Releases page. We welcome feedback on the SBOM.

Erlang/OTP 28 is a new major release with new features, improvements as well as a few incompatibilities. Some of the new features are
highlighted below.

Many thanks to all contributors!

HIGHLIGHTS

New language features

• Comprehensions have been extended with "zip generators" allowing multiple generators to be run in parallel. For example, [A+B || A <- [1,2,3] && B <- [4,5,6]] will produce [5,7,9].

• Generators in comprehensions can now be strict, meaning that if the generator pattern does not match, an exception will be raised instead of silently ignore the value that didn't match.

• It is now possible to use any base for floating point numbers as per EEP 75: Based Floating Point Literals.

Compiler and JIT improvements

• For certain types of errors, the compiler can now suggest corrections. For example, when attempting to use variable A that is not defined but A0 is, the compiler could emit the following message: variable 'A' is unbound, did you mean 'A0'?

• The size of an atom in the Erlang source code was limited to 255 bytes in previous releases, meaning that an atom containing only emojis could contain only 63 emojis. While atoms are still only allowed to contain 255 characters, the number of bytes is no longer limited.

• The warn_deprecated_catch option enables warnings for use of old-style catch expressions on the form catch Expr instead of the modern try ... catch ... end.

• Provided that the map argument for a maps:put/3 call is known to the compiler to be a map, the compiler will replace such calls with the corresponding update using the map syntax.

• Some BIFs with side-effects (such as binary_to_atom/1) are optimized in try ... catch in the same way as guard BIFs in order to gain performance.

• The compiler’s alias analysis pass is now both faster and less conservative, allowing optimizations of records and binary construction to be applied in more cases.

ERTS

• The trace:system/3 function has been added. It has a similar interface as erlang:system_monitor/2 but it also supports trace sessions.

• os:set_signal/2 now supports setting handlers for the SIGWINCH, SIGCONT, and SIGINFO signals.

• The two new BIFs erlang:processes_iterator/0 and erlang:process_next/1 make it possible to iterate over the process table in a way that scales better than erlang:processes/0.

Shell and terminal

• The erl -noshell mode has been updated to have two sub modes called raw and cooked, where cooked is the old default behaviour and raw can be used to bypass the line-editing support of the native terminal. Using raw mode it is possible to read keystrokes as they occur without the user having to press Enter. Also, the raw mode does not echo the typed characters to stdout.

• The shell now prints a help message explaining how to interrupt a running command when stuck executing a command for longer than 5 seconds.

STDLIB

• The join(Binaries, Separator) function that joins a list of binaries has been added to the binary module.

• By default, sets created by module sets will now be represented as maps.

• Module re has been updated to use the newer PCRE2 library instead of the PCRE library.

• There is a new zstd module that does Zstandard compression.

Dialyzer

• EEP 69: Nominal Types has been implemented.

SSL

• The data handling for tls-v1.3 has been optimized.

Emacs mode (in the Tools application)

• The indent-region in Emacs command will now handle multiline strings better.

For more details about new features and potential incompatibilities see the README.