Erlang/OTP 27.0

This release of Erlang/OTP can be built from source or installed using pre-built packages for your OS or third-party tools (such as kerl or asdf).

docker run -it erlang:27.0
Erlang/OTP 27.0
View on github.com
Initial Release OTP 27.0
Git Tag OTP-27.0
Date 2024-05-20
Issue Id
BL-312
BL-322
ERIERL-43
ERIERL-964
ERIERL-967
ERIERL-985
System OTP
Release 27
Application
Potential Incompatibilities

Highlights #

OTP-18606
Application(s):
public_key, ssl
Related Id(s):

OTP-16448, OTP-16875

The ssl client can negotiate and handle certificate status request (OCSP stapling support on the client side).

Thanks to voltone for interop testing and related discussions.

OTP-18622
Application(s):
stdlib
Related Id(s):

PR-7183, PR-7232

The functions is_equal/2, map/2, and filtermap/2 have been added to the modules sets, ordsets, and gb_sets.

OTP-18648
Application(s):
compiler, stdlib
Related Id(s):

PR-7383

The compiler now emits nicer error message for function head mismatches. For example, given:

a() -> ok;
a(_) -> error.

Erlang/OTP 26 and earlier would emit a diagnostic similar to:

t.erl:6:1: head mismatch
%    6| a(_) -> error.
%     | ^

while in Erlang/OTP 27 the diagnostic is similar to:

t.erl:6:1: head mismatch: function a with arities 0 and 1 is regarded as two distinct functions. Is the number of arguments incorrect or is the semicolon in a/0 unwanted?
%    6| a(_) -> error.
%     | ^
OTP-18680
Application(s):
compiler
Related Id(s):

ERIERL-967, PR-7491, PR-8086

The compiler will now merge consecutive updates of the same record.

As an example, the body of the following function will be combined into a single tuple creation instruction:

-record(r, {a,b,c,d}).

update(Value) ->
    R0 = #r{},
    R1 = R0#r{a=Value},
    R2 = R1#r{b=2},
    R2#r{c=3}.
OTP-18717
POTENTIAL INCOMPATIBILITY
 

As announced in OTP 26.1, 0.0 is no longer considered equivalent to -0.0 when using the term equivalence operators (=:= and =/=).

The arithmetic equality operators (== and /=) and all relative comparison operations still consider 0.0 equal to -0.0.

OTP-18744
Application(s):
erts
Related Id(s):

PR-7470

The erl command now supports the -S flag, which is similar to the -run flag, except that it will pass all arguments up to end of the command line to the called function. (The -run flag will not pass arguments beginning with a hyphen.) Another difference is that -S will always call a function with one argument, passing an empty list if no arguments were given.

OTP-18750
POTENTIAL INCOMPATIBILITY
 

Triple-Quoted Strings has been implemented as per EEP 64. See String in the Reference Manual.

Example:

1> """
   a
   b
   c
   """.
"a\nb\nc"

Adjacent string literals without intervening white space is now a syntax error, to avoid possible confusion with triple-quoted strings. For example:

1> "abc""xyz".
"xyz".
* 1:6: adjacent string literals without intervening white space
OTP-18756
Application(s):
tools
Related Id(s):

PR-6639

There is a new tool tprof, which combines the functionality of eprof and cprof under one interface and adds heap profiling. It also has functionality to help with profiling process hierarchies.

Example:

1> tprof:profile(lists, seq, [1, 16], #{type => call_memory}).

****** Process <0.92.0>  --  100.00% of total ***
FUNCTION          CALLS  WORDS  PER CALL  [     %]
lists:seq_loop/3      5     32      6.40  [100.00]
                            32            [ 100.0]
ok
OTP-18808
Application(s):
stdlib
Related Id(s):

PR-7649

Several new functions that accept funs have been added to module timer.

Functions apply_after/2, apply_interval/2, and apply_repeatedly/2 accept a nullary fun as the second argument, while functions apply_after/3, apply_interval/3, and apply_repeatedly/3 accept an n-ary fun as the second and a list of n arguments for the fun as the third argument.

OTP-18825
Application(s):
stdlib
Related Id(s):

PR-7684, OTP-18750

Sigils on string literals have been implemented as per EEP 66, that is: binary and string sigils in verbatim and escape characters variants, as well as a default (vanilla) Sigil. All for ordinary strings and for triple-quoted strings (EEP 64). See Sigils in the Reference Manual.

Examples:

1> ~"Björn".
<<"Björn"/utf8>>
2> ~b"Björn".
<<"Björn"/utf8>>
3> ~S"\s*(\w+)".
"\\s*(\\w+)"
4> ~B"\s*(\w+)".
<<"\\s*(\\w+)">>
OTP-18856
Application(s):
compiler, erts, kernel, tools
Related Id(s):

PR-7856

Native coverage support has been implemented in the JIT. It will automatically be used by the cover tool to reduce the execution overhead when running cover-compiled code.

There are also new APIs to support native coverage without using the cover tool.

To instrument code for native coverage it must be compiled with the line_coverage option.

To enable native coverage in the runtime system, start it like so:

$ erl +JPcover true

There are also the following new functions for supporting native coverage:

  • code:coverage_support/0
  • code:get_coverage/2
  • code:reset_coverage/1
  • code:get_coverage_mode/0
  • code:get_coverage_mode/1
  • code:set_coverage_mode/1
OTP-18916
Application(s):
compiler, stdlib
Related Id(s):

PR-7936

EEP-59 - Documentation Attributes has been implemented.

Documentation attributes can be used to document functions, types, callbacks, and modules. The keyword -moduledoc "Documentation here". is used to document modules, while -doc "Documentation here". can be used on top of functions, types, and callbacks to document them, respectively.

  • Types, callbacks, and function documentation can be set to hidden either via -doc false or -doc hidden. When documentation attributes mark a type as hidden, they will not be part of the documentation.
  • The documentation from moduledoc and doc gets added by default to the binary beam file, following the format of EEP-48.
  • Using the compiler flag warn_missing_doc will raise a warning when -doc attributes are missing in exported functions, types, and callbacks.
  • Using the compiler flag warn_missing_spec_documented will raise a warning when spec attributes are missing in documented functions, types, and callbacks.
  • moduledocs and docs may refer to external files to be embedded, such as -doc {file, "README.md"}., which refers to the file README.md found in the current working directory.
  • The compiler warns about exported functions whose specs refer to hidden types. Thus, there will be warnings when a hidden type (meaning, the type is not part of the documentation) gets used in an exported function.
OTP-18923
Application(s):
stdlib
Related Id(s):

PR-6791

New ets functions ets:first_lookup/1, ets:next_lookup/2, ets:prev_lookup/2 and ets:last_lookup/1. Example: ets:next_lookup/1 is equivalent to ets:next/2 followed by ets:lookup/2 with the next key. The new combined functions are more efficient and with guaranteed atomicity.

OTP-18944
Application(s):
otp, stdlib
Related Id(s):

PR-8067

The maybe expression is now enabled by default.

To use maybe as an atom, it needs to be single-quoted. Alternatively, the maybe expression can be disabled by disabling the maybe_expr feature. That can be done by placing the following the line at the beginning of an Erlang source file:

-feature(maybe_expr, disable).

Another way to disable the maybe_expr feature is by passing the -disable-feature option to erlc:

erlc -disable-feature maybe_expr some_file.erl
OTP-18955
Application(s):
asn1, common_test, compiler, crypto, debugger, dialyzer, diameter, edoc, eldap, erl_interface, erts, et, eunit, ftp, inets, jinterface, kernel, megaco, mnesia, observer, odbc, os_mon, parsetools, public_key, reltool, runtime_tools, sasl, snmp, ssh, ssl, stdlib, syntax_tools, tftp, tools, wx, xmerl
Related Id(s):

PR-8026

The documentation has been migrated to use Markdown and ExDoc.

OTP-18972
Application(s):
compiler, erts
Related Id(s):

PR-8090

Safe destructive update of tuples has been implemented in the compiler and runtime system. This allows the VM to update tuples in-place when it is safe to do so, thus improving performance by doing less copying but also by producing less garbage.

Example:

-record(rec, {a,b,c}).

update(#rec{a=needs_update,b=N}=R0) ->
    R = R0#rec{a=up_to_date},
    if
        N < 0 ->
            R#rec{c=negative};
        N == 0 ->
            R#rec{c=zero};
        N > 0 ->
            R#rec{c=positive}
    end.

The record updates in each of the three clauses of the if can safely be done in-place, because variable R is not used again.

OTP-18980
Application(s):
erts, kernel

There is a new module trace in Kernel providing the same trace functionality as erlang:trace/3 and erlang:trace_pattern/3, but with the addition of dynamic isolated trace sessions.

OTP-19018
Application(s):
asn1
Related Id(s):

PR-8241

The jer (JSON Encoding Rules) for ASN.1 now use the new json module for encoding and decoding JSON. Thus, there is no longer any need for an external JSON library.

OTP-19020
Application(s):
stdlib
Related Id(s):

PR-8111

There is a new module json for encoding and decoding JSON.

Both encoding and decoding can be customized. Decoding can be done in a SAX-like fashion and handle multiple documents and streams of data.

OTP-19025
POTENTIAL INCOMPATIBILITY
 

For security reasons, the CBC ciphers are now longer included in the list of default ciphers for TLS-1.2.

Potential Incompatibilities #

OTP-18594
Application(s):
erts
Related Id(s):

PR-7274

The pid field returned from erlang:fun_info/1,2 is now always the pid for the init process of the local node, not the pid for the actual process that created the fun.

OTP-18639
Application(s):
erts
Related Id(s):

PR-7348

By default, escripts will now be compiled instead of interpreted. That means that the compiler application must be installed.

OTP-18641
Application(s):
inets
Related Id(s):

PR-7316

Introduced a default value for httpd_server name configuration to improve ease of use.

OTP-18717
HIGHLIGHT
 

As announced in OTP 26.1, 0.0 is no longer considered equivalent to -0.0 when using the term equivalence operators (=:= and =/=).

The arithmetic equality operators (== and /=) and all relative comparison operations still consider 0.0 equal to -0.0.

OTP-18750
HIGHLIGHT
 

Triple-Quoted Strings has been implemented as per EEP 64. See String in the Reference Manual.

Example:

1> """
   a
   b
   c
   """.
"a\nb\nc"

Adjacent string literals without intervening white space is now a syntax error, to avoid possible confusion with triple-quoted strings. For example:

1> "abc""xyz".
"xyz".
* 1:6: adjacent string literals without intervening white space
OTP-18784
Application(s):
compiler, otp, stdlib
Related Id(s):

GH-7706, PR-7726

The documentation for the preprocessor now mentions that defined(Name) can be called in the condition for an -if or -elif directive to test whether Name is the name of a defined macro. (This feature was implemented in OTP 21.)

If a function call in an -if or -elif with a name that is not the name of a guard BIF, there would not be a compilation error, but would instead cause the lines following the directive to be skipped. This has now been changed to be a compilation error.

OTP-18966
Application(s):
kernel, otp
Related Id(s):

PR-8091

The existing experimental support for archive files will be changed in a future release. The support for having an archive in an escript will remain, but the support for using archives in a release will either become more limited or completely removed.

As of Erlang/OTP 27, the function code:lib_dir/2, the -code_path_choice flag, and using erl_prim_loader for reading members of an archive are deprecated.

To remain compatible with future version of Erlang/OTP escript scripts that need to retrieve data files from its archive should use escript:extract/2 instead of erl_prim_loader and code:lib_dir/2.

OTP-18968
Application(s):
compiler
Related Id(s):

GH-6979, PR-8093

The order in which the compiler looks up options has changed.

When there is a conflict in the compiler options given in the -compile() attribute and options given to the compiler, the options given in the -compile() attribute overrides the option given to the compiler, which in turn overrides options given in the ERL_COMPILER_OPTIONS environment variable.

Example:

If some_module.erl has the following attribute:

-compile([nowarn_missing_spec]).

and the compiler is invoked like so:

% erlc +warn_missing_spec some_module.erl

no warnings will be issued for functions that do not have any specs.

OTP-19016
Application(s):
crypto, public_key
Related Id(s):

PR-8233

The existing function ssl:key_exporter_materials/4 is now documented and supported.

OTP-19022
Application(s):
inets

The implementations of http_uri:encode/1 and http_uri:decode/1 are now replaced with their equivalent, but bug free versions from module uri_string, namely uri_string:quote/1 and uri_string:unquote/1.

OTP-19025
HIGHLIGHT
 

For security reasons, the CBC ciphers are now longer included in the list of default ciphers for TLS-1.2.

OTP-19029
Application(s):
stdlib
Related Id(s):

PR-8230

The error handling the simple_one_for_one supervisor has been enhanced. A transient child returning ignore will no longer cause a crash.

Also, automatic shutdown has been disabled because it does not make sense for this supervisor type. That is was allowed is considered a bug. Therefore, we don’t consider this an incompatible change.

OTP-19075
Application(s):
crypto, public_key

Due to another attack on PKCS #1 v1.5 padding, known as the Marvin attack, about which we were alerted by Hubert Kario from Red Hat. You can find more details about the attack at https://people.redhat.com/~hkario/marvin/ Functions that may be vulnerable are now deprecated.

Note that you might mitigate the problem by using appropriate versions of OpenSSL together with our software, but we recommend not using them at all.

Also avoid using TLS versions prior to TLS-1.2 (not supported by default) and do not enable RSA-key exchange cipher suites (not supported by default).

OTP-19079
Application(s):
xmerl
Related Id(s):

GH-7539

Some default values in Xmerl has been changed to avoid XML External Entity (XXE) vulnerabilities if you’re parsing untrusted XML.

xmerl_scan: the default value for allow_entities has changed to false. xmerl_sax_parser: the default value for external_entities has changed to none.

OTP-27.0 #

OTP-18717
HIGHLIGHT, POTENTIAL INCOMPATIBILITY
 

As announced in OTP 26.1, 0.0 is no longer considered equivalent to -0.0 when using the term equivalence operators (=:= and =/=).

The arithmetic equality operators (== and /=) and all relative comparison operations still consider 0.0 equal to -0.0.

OTP-18784
POTENTIAL INCOMPATIBILITY
 

The documentation for the preprocessor now mentions that defined(Name) can be called in the condition for an -if or -elif directive to test whether Name is the name of a defined macro. (This feature was implemented in OTP 21.)

If a function call in an -if or -elif with a name that is not the name of a guard BIF, there would not be a compilation error, but would instead cause the lines following the directive to be skipped. This has now been changed to be a compilation error.

OTP-18943

configure scripts of the OTP build system are now generated using Autoconf 2.72.

OTP-18944
HIGHLIGHT
 

The maybe expression is now enabled by default.

To use maybe as an atom, it needs to be single-quoted. Alternatively, the maybe expression can be disabled by disabling the maybe_expr feature. That can be done by placing the following the line at the beginning of an Erlang source file:

-feature(maybe_expr, disable).

Another way to disable the maybe_expr feature is by passing the -disable-feature option to erlc:

erlc -disable-feature maybe_expr some_file.erl
OTP-18965
Related Id(s):

PR-8095

By default configure scripts used when building OTP will now try to enable support for timestamps that will work after mid-January 2038. This has typically only been an issue on 32-bit platforms.

If configure cannot figure out how to enable such timestamps, it will abort with an error message. If you want to build the system anyway, knowing that the system will not function properly after mid-January 2038, you can pass the --disable-year2038 option to configure, which will enable configure to continue without support for timestamps after mid-January 2038.

OTP-18966
POTENTIAL INCOMPATIBILITY
 

The existing experimental support for archive files will be changed in a future release. The support for having an archive in an escript will remain, but the support for using archives in a release will either become more limited or completely removed.

As of Erlang/OTP 27, the function code:lib_dir/2, the -code_path_choice flag, and using erl_prim_loader for reading members of an archive are deprecated.

To remain compatible with future version of Erlang/OTP escript scripts that need to retrieve data files from its archive should use escript:extract/2 instead of erl_prim_loader and code:lib_dir/2.

OTP-18995
Related Id(s):

GH-8166, PR-8177

The restriction for the expression that gives a default value for a record field is now documented.

asn1-5.3 #

OTP-18813
Related Id(s):

PR-7790

Multiple bugs has been eliminated in the specialized decode feature.

OTP-18804
Related Id(s):

PR-7738

Specs have been added to all asn1ct API functions.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19018
HIGHLIGHT
 

The jer (JSON Encoding Rules) for ASN.1 now use the new json module for encoding and decoding JSON. Thus, there is no longer any need for an external JSON library.

Full runtime dependencies of asn1-5.3

erts-14.0, kernel-9.0, stdlib-5.0

common_test-1.27 #

OTP-18658
Related Id(s):

PR-7380

Calls to ct:capture_start/0 and ct:capture_stop/0 are now synchronous to ensure that all output is captured.

OTP-18682
Related Id(s):

ERIERL-43, GH-7397, PR-7496

The order in which multiple hooks are executed can now be reversed after each config function. See CTH Execution Order.

OTP-18761
Related Id(s):

PR-7428

The default CSS will now include a basic dark mode handling if it is preferred by the browser.

OTP-18781
Related Id(s):

PR-7701

-callback attributes have been added to ct_suite and ct_hooks.

OTP-18875
Related Id(s):

PR-7891

The built-in cth_log_redirect hook can now be configured to replace default logger reports in terminal with HTML logs.

OTP-18881
Related Id(s):

PR-7824

Error handling for the ct_property_test framework has been enhanced.

OTP-18892
Related Id(s):

PR-7869

Enhance test case documentation, making it clear how a test case can be failed.

OTP-18898
Related Id(s):

PR-7917

The failing line in the test source code is now colored to make it easier to find on the screen.

OTP-18913

Function specifications and types have been added to all public API functions.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-18981
Related Id(s):

GH-7972, PR-8112

The suite execution elapsed time is now included in the index page.

Full runtime dependencies of common_test-1.27

compiler-6.0, crypto-4.5, debugger-4.1, erts-7.0, ftp-1.0, inets-6.0, kernel-8.4, observer-2.1, runtime_tools-1.8.16, sasl-2.5, snmp-5.1.2, ssh-4.0, stdlib-4.0, syntax_tools-1.7, tools-3.2, xmerl-1.3.8

compiler-8.5 #

OTP-18703
Related Id(s):

GH-7494, PR-7538

Generators for binary comprehensions could be evaluated before it was known that they would be needed. That could result in a binary comprehensions failing if a generator that should not be evaluated until later failed.

As an example, consider this module:

-module(t).
-export([f/0]).

f() ->
    <<0 || _ <- [], _ <- ok, false>>.

In Erlang/OTP 26 it would fail like so:

1> t:f().
** exception error: bad generator ok
     in function  t:f/0 (t.erl, line 6)

In Erlang/OTP 27 it returns an empty binary:

1> t:f().
<<>>
OTP-18784
POTENTIAL INCOMPATIBILITY
 

The documentation for the preprocessor now mentions that defined(Name) can be called in the condition for an -if or -elif directive to test whether Name is the name of a defined macro. (This feature was implemented in OTP 21.)

If a function call in an -if or -elif with a name that is not the name of a guard BIF, there would not be a compilation error, but would instead cause the lines following the directive to be skipped. This has now been changed to be a compilation error.

OTP-18648
HIGHLIGHT
 

The compiler now emits nicer error message for function head mismatches. For example, given:

a() -> ok;
a(_) -> error.

Erlang/OTP 26 and earlier would emit a diagnostic similar to:

t.erl:6:1: head mismatch
%    6| a(_) -> error.
%     | ^

while in Erlang/OTP 27 the diagnostic is similar to:

t.erl:6:1: head mismatch: function a with arities 0 and 1 is regarded as two distinct functions. Is the number of arguments incorrect or is the semicolon in a/0 unwanted?
%    6| a(_) -> error.
%     | ^
OTP-18673
Related Id(s):

ERIERL-964, PR-7474

The compiler now optimizes creation of binaries that are known to be constant.

Consider this example:

bin() ->
    C = char(),
    <<C>>.

char() -> $*.

Essentially, the compiler rewrites the example to the slightly more efficient:

bin() ->
    _ = char(),
    <<$*>>.

char() -> $*.
OTP-18680
HIGHLIGHT
 

The compiler will now merge consecutive updates of the same record.

As an example, the body of the following function will be combined into a single tuple creation instruction:

-record(r, {a,b,c,d}).

update(Value) ->
    R0 = #r{},
    R1 = R0#r{a=Value},
    R2 = R1#r{b=2},
    R2#r{c=3}.
OTP-18714
Related Id(s):

GH-7432, PR-7528

Improved the performance of the alias analysis pass.

OTP-18801
Related Id(s):

PR-7739

-spec attributes are now used for documentation.

OTP-18856
HIGHLIGHT
 

Native coverage support has been implemented in the JIT. It will automatically be used by the cover tool to reduce the execution overhead when running cover-compiled code.

There are also new APIs to support native coverage without using the cover tool.

To instrument code for native coverage it must be compiled with the line_coverage option.

To enable native coverage in the runtime system, start it like so:

$ erl +JPcover true

There are also the following new functions for supporting native coverage:

  • code:coverage_support/0
  • code:get_coverage/2
  • code:reset_coverage/1
  • code:get_coverage_mode/0
  • code:get_coverage_mode/1
  • code:set_coverage_mode/1
OTP-18916
HIGHLIGHT
 

EEP-59 - Documentation Attributes has been implemented.

Documentation attributes can be used to document functions, types, callbacks, and modules. The keyword -moduledoc "Documentation here". is used to document modules, while -doc "Documentation here". can be used on top of functions, types, and callbacks to document them, respectively.

  • Types, callbacks, and function documentation can be set to hidden either via -doc false or -doc hidden. When documentation attributes mark a type as hidden, they will not be part of the documentation.
  • The documentation from moduledoc and doc gets added by default to the binary beam file, following the format of EEP-48.
  • Using the compiler flag warn_missing_doc will raise a warning when -doc attributes are missing in exported functions, types, and callbacks.
  • Using the compiler flag warn_missing_spec_documented will raise a warning when spec attributes are missing in documented functions, types, and callbacks.
  • moduledocs and docs may refer to external files to be embedded, such as -doc {file, "README.md"}., which refers to the file README.md found in the current working directory.
  • The compiler warns about exported functions whose specs refer to hidden types. Thus, there will be warnings when a hidden type (meaning, the type is not part of the documentation) gets used in an exported function.
OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-18968
POTENTIAL INCOMPATIBILITY
 

The order in which the compiler looks up options has changed.

When there is a conflict in the compiler options given in the -compile() attribute and options given to the compiler, the options given in the -compile() attribute overrides the option given to the compiler, which in turn overrides options given in the ERL_COMPILER_OPTIONS environment variable.

Example:

If some_module.erl has the following attribute:

-compile([nowarn_missing_spec]).

and the compiler is invoked like so:

% erlc +warn_missing_spec some_module.erl

no warnings will be issued for functions that do not have any specs.

OTP-18972
HIGHLIGHT
 

Safe destructive update of tuples has been implemented in the compiler and runtime system. This allows the VM to update tuples in-place when it is safe to do so, thus improving performance by doing less copying but also by producing less garbage.

Example:

-record(rec, {a,b,c}).

update(#rec{a=needs_update,b=N}=R0) ->
    R = R0#rec{a=up_to_date},
    if
        N < 0 ->
            R#rec{c=negative};
        N == 0 ->
            R#rec{c=zero};
        N > 0 ->
            R#rec{c=positive}
    end.

The record updates in each of the three clauses of the if can safely be done in-place, because variable R is not used again.

OTP-18987

Improved the match context reuse optimization slightly, allowing match contexts to be passed as-is to bit_size/1 and byte_size/1.

OTP-19010
Related Id(s):

PR-8205

m:erl_lint (and by extension the compiler) will now warn for code using deprecated callbacks.

The only callback currenly deprecated is format_status/2 in gen_server, gen_event and gen_statem.

You can use nowarn_deprecated_callback to silence the warning.

Full runtime dependencies of compiler-8.5

crypto-5.1, erts-13.0, kernel-8.4, stdlib-6.0

crypto-5.5 #

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-18973

Removed functions crypto_dyn_iv_init/3 and crypto_dyn_iv_update/3 which were marked as deprecated since OTP 25.

OTP-18975
Related Id(s):

PR-6658

Add support for sm3 hash and hmac.

OTP-18978
Related Id(s):

PR-7809

OPENSSL_thread_stop is called when crypto is purged to not leak thread specific data.

OTP-19005
Related Id(s):

PR-8168

Add SM4 block cipher implemented according to GB/T 32907-2016.

OTP-19016
POTENTIAL INCOMPATIBILITY
 

The existing function ssl:key_exporter_materials/4 is now documented and supported.

OTP-19075

Due to another attack on PKCS #1 v1.5 padding, known as the Marvin attack, about which we were alerted by Hubert Kario from Red Hat. You can find more details about the attack at https://people.redhat.com/~hkario/marvin/ Functions that may be vulnerable are now deprecated.

Note that you might mitigate the problem by using appropriate versions of OpenSSL together with our software, but we recommend not using them at all.

Also avoid using TLS versions prior to TLS-1.2 (not supported by default) and do not enable RSA-key exchange cipher suites (not supported by default).

Full runtime dependencies of crypto-5.5

erts-9.0, kernel-5.3, stdlib-3.9

debugger-5.4 #

OTP-18831
Related Id(s):

PR-7441

The dependencies for this application are now listed in the app file.

OTP-18819
Related Id(s):

PR-7781

Type specs have been added to all API functions.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19074
Related Id(s):

PR-8389

The Debugger now use a trace session for its internal use of tracing to avoid interfering with the user’s use of tracing.

Full runtime dependencies of debugger-5.4

compiler-8.0, erts-15.0, kernel-10.0, stdlib-3.15, wx-2.0

dialyzer-5.2 #

OTP-18667
Related Id(s):

PR-7443

The --gui option for Dialyzer has been removed.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of dialyzer-5.2

compiler-8.0, erts-12.0, kernel-8.0, stdlib-5.0, syntax_tools-2.0

diameter-2.4 #

OTP-18783
Related Id(s):

PR-7699

-callback attributes have been added to diameter_app and diameter_transport.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19090
Related Id(s):

PR-8399

Pick peer can now also handle request of type #diameter_packet{}.

Full runtime dependencies of diameter-2.4

erts-10.0, kernel-3.2, ssl-9.0, stdlib-5.0

edoc-1.3 #

OTP-18945
Related Id(s):

PR-8063

EEP 48 doc chunks now properly include links within {@type } macros.

OTP-18946
Related Id(s):

PR-8063

@hidden now means hidden in EEP 48 doc chunks instead of none.

OTP-18947
Related Id(s):

PR-8063

There is a new edoc_html_to_markdown module that can be used to convert EEP-48 application/html+erlang to Markdown.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19052
Related Id(s):

PR-8308

Added module edoc_doclet_markdown that can be used to convert EDoc style documentation to Markdown documentation attributes.

Full runtime dependencies of edoc-1.3

erts-11.0, inets-5.10, kernel-7.0, stdlib-4.0, syntax_tools-2.0, xmerl-1.3.7

eldap-1.2.13 #

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of eldap-1.2.13

asn1-3.0, erts-6.0, kernel-3.0, ssl-5.3.4, stdlib-3.4

erl_interface-5.5.2 #

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-16607
Related Id(s):

OTP-16608

The ei API for decoding/encoding terms is not fully 64-bit compatible since terms that have a representation on the external term format larger than 2 GB cannot be handled.

erts-15.0 #

OTP-18766
Related Id(s):

PR-7639

Bugs in how erl -extra interacts with passing flags via ERL_*FLAGS or -args_file have been fixed.

OTP-18918
Related Id(s):

PR-7952

Fixed a bug that prevented the emulator from building on recent versions of Yocto Linux.

OTP-18928
Related Id(s):

PR-8006

Fixed spectre mitigation configure test to work with GCC patches to always add -fcf-protection=full.

OTP-19063
Related Id(s):

OTP-18835

A call to socket:[recv|recvfrom|recvmsg]/* with Timeout = 0 on Windows could cause a (case clause) crash if data is immediately available.

OTP-19077
Related Id(s):

PR-8324

Fix bug on Windows where exit_status would not be sent when a port exits after the stdin/stdout handles have been closed.

OTP-18568
Related Id(s):

PR-7174

Refactored how the JIT handles POSIX signals and how they affect thread stacks, allowing us to use the native stack register for Erlang stacks on more platforms.

Notably, containers built on 64-bit x86 Alpine Linux images will now perform much better in sequential code. As an example, running dialyzer over the OTP code base finishes about 15% quicker.

OTP-18577
Related Id(s):

PR-7236

The instrument module can now track allocations on a per-process or per-port basis.

OTP-18594
POTENTIAL INCOMPATIBILITY
 

The pid field returned from erlang:fun_info/1,2 is now always the pid for the init process of the local node, not the pid for the actual process that created the fun.

OTP-18639
POTENTIAL INCOMPATIBILITY
 

By default, escripts will now be compiled instead of interpreted. That means that the compiler application must be installed.

OTP-18642
Related Id(s):

GH-6152, PR-7465

A binary returned from the socket receive functions is no longer created as a sub binary of an often large receive buffer binary (socket option {otp,rcvbuf}). This avoids space waste, trusting the allocators to implement reallocation efficiently.

OTP-18699
Related Id(s):

PR-7388

The default process limit has been raised to 1048576 processes.

OTP-18709
Related Id(s):

PR-7651

The erlang:system_monitor/2 functionality is now able to monitor long message queues in the system.

OTP-18744
HIGHLIGHT
 

The erl command now supports the -S flag, which is similar to the -run flag, except that it will pass all arguments up to end of the command line to the called function. (The -run flag will not pass arguments beginning with a hyphen.) Another difference is that -S will always call a function with one argument, passing an empty list if no arguments were given.

OTP-18774
Related Id(s):

PR-7110

When implementing an alternative carrier for the Erlang distribution, a separate input handler process may now be registered, using erlang:dist_ctrl_input_handler/2, also in the case when the distribution controller is a port.

OTP-18779
Related Id(s):

PR-7592

The call stack trace has now been added to the error reported by erlang:process_flag/2 when max_heap_size limit has been exceeded.

OTP-18794
Related Id(s):

PR-7703

-callback attributes have been added to erl_tracer.

OTP-18835

For inet_backend = socket, setting the active socket option alone, to once, true or N has been optimized, as well as the corresponding data delivery.

OTP-18845

New functions socket:sendv/* for sending I/O vectors have been added.

OTP-18849
Related Id(s):

PR-6510

Socket options that take string now also accept binaries.

OTP-18856
HIGHLIGHT
 

Native coverage support has been implemented in the JIT. It will automatically be used by the cover tool to reduce the execution overhead when running cover-compiled code.

There are also new APIs to support native coverage without using the cover tool.

To instrument code for native coverage it must be compiled with the line_coverage option.

To enable native coverage in the runtime system, start it like so:

$ erl +JPcover true

There are also the following new functions for supporting native coverage:

  • code:coverage_support/0
  • code:get_coverage/2
  • code:reset_coverage/1
  • code:get_coverage_mode/0
  • code:get_coverage_mode/1
  • code:set_coverage_mode/1
OTP-18894
Related Id(s):

PR-7243

Changed the default value of the command line flag -code_path_choice to strict.

Note that for application systems using archives, it is necessary to add the code_path_choice relaxed to the command line that invokes erl.

OTP-18929
Related Id(s):

PR-8004

Added module loading to erl -init_debug printouts.

OTP-18938
Related Id(s):

GH-7438, PR-8035

When the runtime system halts, it performs various flush operations before terminating. By default there is no limit on how much time the flush operations are allowed to take. A new halt flush timeout functionality has been introduced which can be used for limiting the amount of time that the flushing operations are allowed to take. For more information see the documentation of the flush_timeout option of the erlang:halt/2 BIF and the documentation of the erl +zhft <Timeout> command line flag.

OTP-18941
Related Id(s):

PR-7981

Optimized code loading by moving certain operations from the code server to the caller.

OTP-18942

Updated asmjit to version a465fe71ab3d0e224b2b4bd0fac69ae68ab9239d

OTP-18950

The deprecated functions in zlib have been removed. That includes inflateChunk/{1,2}, getBufSize/1, setBufSize/2, the CRC32 functions, and the Adler checksum functions.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-18972
HIGHLIGHT
 

Safe destructive update of tuples has been implemented in the compiler and runtime system. This allows the VM to update tuples in-place when it is safe to do so, thus improving performance by doing less copying but also by producing less garbage.

Example:

-record(rec, {a,b,c}).

update(#rec{a=needs_update,b=N}=R0) ->
    R = R0#rec{a=up_to_date},
    if
        N < 0 ->
            R#rec{c=negative};
        N == 0 ->
            R#rec{c=zero};
        N > 0 ->
            R#rec{c=positive}
    end.

The record updates in each of the three clauses of the if can safely be done in-place, because variable R is not used again.

OTP-18976
Related Id(s):

PR-7125

The obsolete and undocumented support for opening a port to an external resource by passing an atom (or a string) as first argument to open_port(), implemented by the vanilla driver, has been removed. This feature has been scheduled for removal in OTP 27 since the release of OTP 26.

OTP-18977
Related Id(s):

PR-7809

An optional NIF callback ERL_NIF_OPT_ON_UNLOAD_THREAD to be called by all scheduler threads when a NIF library is unloaded. Used for releasing thread specific data. Can be set with function enif_set_option.

OTP-18980

There is a new module trace in Kernel providing the same trace functionality as erlang:trace/3 and erlang:trace_pattern/3, but with the addition of dynamic isolated trace sessions.

OTP-18984
Related Id(s):

PR-7977

Added the +MMlp on|off emulator option to let the mseg allocator use “large pages” (sometimes known as “huge pages” or “super pages”). This currently only affects super-carrier allocations, but may be extended in the future.

OTP-19004
Related Id(s):

OTP-18835

inet_backend = socket has been optimized and reworked to be more compatible with the original inet_backend = inet.

OTP-19054

The socket documentation has been reworked, and due to that a few details were fixed:

  • socket:is_supported/1 now returns true for example for protocols that is a “category”, not an item.
  • socket:cancel_monitor/1 no longer badargs for a monitor that was set by another process, instead it returns false as for other unknown reference()s.

Full runtime dependencies of erts-15.0

kernel-9.0, sasl-3.3, stdlib-4.1

et-1.7.1 #

OTP-18831
Related Id(s):

PR-7441

The dependencies for this application are now listed in the app file.

OTP-18860

Dialyzer warnings due to type specs added in dbg have been eliminated.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of et-1.7.1

erts-9.0, kernel-5.3, runtime_tools-1.10, stdlib-3.4, wx-1.2

eunit-2.9.1 #

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of eunit-2.9.1

erts-9.0, kernel-5.3, stdlib-3.4

ftp-1.2.2 #

OTP-18860

Dialyzer warnings due to type specs added in dbg have been eliminated.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of ftp-1.2.2

erts-7.0, kernel-6.0, runtime_tools-1.15.1, ssl-10.2, stdlib-3.5

inets-9.2 #

OTP-18641
POTENTIAL INCOMPATIBILITY
 

Introduced a default value for httpd_server name configuration to improve ease of use.

OTP-18727
Related Id(s):

PR-7299

The httpd module has been extended with an API for simple serving directory content over HTTP. With this change, the current working directory can be served like this:

erl -S httpd

An arbitrary directory can be served like this:

erl -S httpd serve path/to/dir
OTP-18786
Related Id(s):

PR-7700

Added -callback attributes to httpd, mod_esi, and mod_security.

OTP-18809
Related Id(s):

GH-7617, PR-7678

Inets now uses a relative redirect with an absolute path to prevent whoever is running Inets from having to configure the ServerName to match the network-reachable host name of the server.

OTP-18927
Related Id(s):

PR-8029

inets processes now use proc_lib:set_label/1 to improve observeability.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19022

The implementations of http_uri:encode/1 and http_uri:decode/1 are now replaced with their equivalent, but bug free versions from module uri_string, namely uri_string:quote/1 and uri_string:unquote/1.

OTP-19033

With this change, the API specs are updated.

Full runtime dependencies of inets-9.2

erts-14.0, kernel-9.0, mnesia-4.12, public_key-1.13, runtime_tools-1.8.14, ssl-9.0, stdlib-5.0, stdlib-6.0

jinterface-1.14.1 #

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

kernel-10.0 #

OTP-18590
Related Id(s):

PR-7220

Fixed a crash when calling file:delete/2 with an empty option list.

OTP-18878
Related Id(s):

GH-7718, OTP-17734

New functions have been added to the undocumented module inet_dns that take a flag to specify if encode/decode is for mDNS. This affects how CLASS values in the private range, with the top bit set, are handled.

OTP-18904
Related Id(s):

PR-7960

The error information for erlang:phash/2 has been corrected.

OTP-18930
Related Id(s):

GH-4992, PR-7993

get_until requests using the I/O protocol now correctly return a binary or list when eof is the last item returned by the callback.

OTP-18954
Related Id(s):

GH-8061, PR-8076

Calling logger:add_handlers/1 with config option now works.

OTP-18959
Related Id(s):

GH-6692, PR-7697

The code:del_path/1 function now also works on paths added through -pa, -pz , -path and the boot script.

OTP-19063
Related Id(s):

OTP-18835

A call to socket:[recv|recvfrom|recvmsg]/* with Timeout = 0 on Windows could cause a (case clause) crash if data is immediately available.

OTP-19087
Related Id(s):

PR-8382

Improve heuristic for when a characters is wide in the shell for systems with old libc versions.

OTP-19088
Related Id(s):

GH-8360, PR-8396

Fix reading a line when reading from io:user/0 to not consider \r without \n to be a new line when erl is started with -noshell.

OTP-18589
Related Id(s):

PR-7220

Added file:read_file/2 with a raw option for reading files without going through the file server.

OTP-18713
Related Id(s):

GH-6985, PR-6985

The undocumented Erlang DNS resolver library (inet_dns and inet_res) has been augmented to handle IXFR, NOTIFY, UPDATE and TSIG records. With this some bug fixes and code cleanup has been done, and the resolver used in the test suite has been changed to Knot DNS. See the source code.

Kudos to Alexander Clouter that did almost all the work!

OTP-18778
Related Id(s):

PR-7556

The ebin directories for escripts are now cached.

OTP-18795
Related Id(s):

PR-7703

-callback attributes haven been added to application, logger_handler, and logger_formatter.

OTP-18807
Related Id(s):

ERIERL-985, PR-7732

Progress reports from before logger is started are now logged when log level is set to debug.

OTP-18816
Related Id(s):

PR-7711

The code:where_is_file/2 and code:which/1 functions now check for existence of the file directly instead of listing the content of each directory in the code path.

OTP-18820
Related Id(s):

PR-7779

Type specs has been added to the logger:Level/1,2,3 functions.

OTP-18835

For inet_backend = socket, setting the active socket option alone, to once, true or N has been optimized, as well as the corresponding data delivery.

OTP-18845

New functions socket:sendv/* for sending I/O vectors have been added.

OTP-18846
Related Id(s):

PR-7845

The shell now pages long output from the documentation help command (h(Module)), auto completions and the search command.

OTP-18856
HIGHLIGHT
 

Native coverage support has been implemented in the JIT. It will automatically be used by the cover tool to reduce the execution overhead when running cover-compiled code.

There are also new APIs to support native coverage without using the cover tool.

To instrument code for native coverage it must be compiled with the line_coverage option.

To enable native coverage in the runtime system, start it like so:

$ erl +JPcover true

There are also the following new functions for supporting native coverage:

  • code:coverage_support/0
  • code:get_coverage/2
  • code:reset_coverage/1
  • code:get_coverage_mode/0
  • code:get_coverage_mode/1
  • code:set_coverage_mode/1
OTP-18941
Related Id(s):

PR-7981

Optimized code loading by moving certain operations from the code server to the caller.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-18963
Related Id(s):

PR-8042

Application startup has been optimized by removing an intermediary process.

OTP-18966
POTENTIAL INCOMPATIBILITY
 

The existing experimental support for archive files will be changed in a future release. The support for having an archive in an escript will remain, but the support for using archives in a release will either become more limited or completely removed.

As of Erlang/OTP 27, the function code:lib_dir/2, the -code_path_choice flag, and using erl_prim_loader for reading members of an archive are deprecated.

To remain compatible with future version of Erlang/OTP escript scripts that need to retrieve data files from its archive should use escript:extract/2 instead of erl_prim_loader and code:lib_dir/2.

OTP-18967
Related Id(s):

PR-8092

The undocumented and deprecated file:pid2name function has been removed.

OTP-18980

There is a new module trace in Kernel providing the same trace functionality as erlang:trace/3 and erlang:trace_pattern/3, but with the addition of dynamic isolated trace sessions.

OTP-18989
Related Id(s):

PR-8103

Error logging has been improved when the io:standard_io/0 reader and/or writer terminates with an error.

OTP-19004
Related Id(s):

OTP-18835

inet_backend = socket has been optimized and reworked to be more compatible with the original inet_backend = inet.

OTP-19042

Add an simple example (echo server) )to the socket users guide.

OTP-19053
Related Id(s):

#6724

inet:i/0,1,2 has been improved to allow port numbers to be shown explicitly.

OTP-19054

The socket documentation has been reworked, and due to that a few details were fixed:

  • socket:is_supported/1 now returns true for example for protocols that is a “category”, not an item.
  • socket:cancel_monitor/1 no longer badargs for a monitor that was set by another process, instead it returns false as for other unknown reference()s.
OTP-19089
Related Id(s):

PR-8396

Add stdin, stdout and stderr keys to io:getopts/1 on io:standard_io/0 to indicate if the respective I/O device is backed by a terminal.

Full runtime dependencies of kernel-10.0

crypto-5.0, erts-15.0, sasl-3.0, stdlib-6.0

megaco-4.6 #

OTP-18806
Related Id(s):

PR-7740

-callback attributes have been added to megaco_transport.

OTP-18920
Related Id(s):

BL-322

Updated types and specs for all API modules.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of megaco-4.6

asn1-3.0, debugger-4.0, erts-12.0, et-1.5, kernel-8.0, runtime_tools-1.8.14, stdlib-2.5

mnesia-4.23.2 #

OTP-18994

The mnesia_registry module have been deprecated.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of mnesia-4.23.2

erts-9.0, kernel-5.3, stdlib-5.0

observer-2.16 #

OTP-18831
Related Id(s):

PR-7441

The dependencies for this application are now listed in the app file.

OTP-18789
Related Id(s):

PR-7720, PR-8003

The new function proc_lib:set_label/1 can be used to add a descriptive term to any process that does not have a registered name. The name will be shown by tools such as \c:i/0, observer, and it will be included in crash reports produced by processes using gen_server, gen_statem, gen_event, and gen_fsm.

The label for a process can be retrieved by calling proc_lib:get_label/1.

Note that those functions work on any process, not only processes that use proc_lib.

Example:

1> self().
<0.90.0>
2> proc_lib:set_label(my_label).
ok
3> i().
    .
    .
    .
<0.90.0>              erlang:apply/2                        2586    75011    0
my_label              c:pinfo/2                               51
4> proc_lib:get_label(self()).
my_label
OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19082
Related Id(s):

PR-8363

m:etop has been updated to use dbg:session/2 in order to not interfere with any other tracing.

Full runtime dependencies of observer-2.16

erts-15.0, et-1.5, kernel-10.0, runtime_tools-2.1, stdlib-5.0, wx-2.3

odbc-2.14.3 #

OTP-19030
Related Id(s):

GH-8244, PR-8258

The order of libs in the Makefile has been changed to avoid finding the system’s libei instead of Erlang’s libei.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of odbc-2.14.3

erts-6.0, kernel-3.0, stdlib-2.0

os_mon-2.10 #

OTP-18913

Function specifications and types have been added to all public API functions.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of os_mon-2.10

erts-14.0, kernel-9.0, sasl-4.2.1, stdlib-5.0

parsetools-2.6 #

OTP-18796
Related Id(s):

PR-7703

The leex documentation has been updated to use specs for documenting the generated interface.

OTP-18912
Related Id(s):

PR-7963

yecc now wraps the -module attribute with -file to indicate the .yrl source file.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of parsetools-2.6

erts-6.0, kernel-3.0, stdlib-3.4

public_key-1.16 #

OTP-18606
HIGHLIGHT
 

The ssl client can negotiate and handle certificate status request (OCSP stapling support on the client side).

Thanks to voltone for interop testing and related discussions.

OTP-18609
Related Id(s):

GH-7295, PR-7302

The exception reason when public_key:cacerts_get/0 failed has been improved.

OTP-18876
Related Id(s):

PR-7475, PR-7898

Key customization support has been extended to allow flexibility for implementers of for instance hardware security modules (HSM) or trusted platform modules (TPM).

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19016
POTENTIAL INCOMPATIBILITY
 

The existing function ssl:key_exporter_materials/4 is now documented and supported.

OTP-19075

Due to another attack on PKCS #1 v1.5 padding, known as the Marvin attack, about which we were alerted by Hubert Kario from Red Hat. You can find more details about the attack at https://people.redhat.com/~hkario/marvin/ Functions that may be vulnerable are now deprecated.

Note that you might mitigate the problem by using appropriate versions of OpenSSL together with our software, but we recommend not using them at all.

Also avoid using TLS versions prior to TLS-1.2 (not supported by default) and do not enable RSA-key exchange cipher suites (not supported by default).

Full runtime dependencies of public_key-1.16

asn1-3.0, crypto-4.6, erts-6.0, kernel-3.0, stdlib-3.5

reltool-1.0.1 #

OTP-18831
Related Id(s):

PR-7441

The dependencies for this application are now listed in the app file.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of reltool-1.0.1

erts-15.0, kernel-9.0, sasl-4.2.1, stdlib-5.0, tools-2.6.14, wx-2.3

runtime_tools-2.1 #

OTP-18577
Related Id(s):

PR-7236

The instrument module can now track allocations on a per-process or per-port basis.

OTP-18789
Related Id(s):

PR-7720, PR-8003

The new function proc_lib:set_label/1 can be used to add a descriptive term to any process that does not have a registered name. The name will be shown by tools such as \c:i/0, observer, and it will be included in crash reports produced by processes using gen_server, gen_statem, gen_event, and gen_fsm.

The label for a process can be retrieved by calling proc_lib:get_label/1.

Note that those functions work on any process, not only processes that use proc_lib.

Example:

1> self().
<0.90.0>
2> proc_lib:set_label(my_label).
ok
3> i().
    .
    .
    .
<0.90.0>              erlang:apply/2                        2586    75011    0
my_label              c:pinfo/2                               51
4> proc_lib:get_label(self()).
my_label
OTP-18859
Related Id(s):

PR-7782

Type specs had been added to all dbg functions.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19081
Related Id(s):

PR-8363

m:dbg have been updated to use trace sessions.

dbg:session_create/1, dbg:session/2, and dbg:session_destroy/1 have been added to work sessions. See the documentation for details.

Full runtime dependencies of runtime_tools-2.1

erts-15.0, kernel-10.0, mnesia-4.12, stdlib-6.0

sasl-4.2.2 #

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of sasl-4.2.2

erts-15.0, kernel-6.0, stdlib-4.0, tools-2.6.14

snmp-5.16 #

OTP-18785
Related Id(s):

PR-7702

-callback attributes have been added to modules snmpa_network_interface_filter, snmpa_notification_filter, snmpm_network_interface_filter, snmpm_user, and snmpa_notification_delivery_info_receiver.

New -type attributes have also been added to modules snmp, snmpa, snmpm, and snmpa_conf to support the previously mentioned callbacks.

OTP-18934
Related Id(s):

BL-312

Updated types and specs for all API modules.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of snmp-5.16

crypto-4.6, erts-12.0, kernel-8.0, mnesia-4.12, runtime_tools-1.8.14, stdlib-5.0

ssh-5.2 #

OTP-19017
Related Id(s):

PR-8249

SSH processes are now assigned labels for troubleshooting purposes.

OTP-19057
Related Id(s):

GH-7483, PR-8345

With this change, ssh client will automatically adjust transfer window size for commands executed remotely over SSH.

OTP-18846
Related Id(s):

PR-7845

The shell now pages long output from the documentation help command (h(Module)), auto completions and the search command.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-18961

Updated types and specs for all API modules.

Full runtime dependencies of ssh-5.2

crypto-5.0, erts-14.0, kernel-9.0, public_key-1.6.1, runtime_tools-1.15.1, stdlib-5.0, stdlib-6.0

ssl-11.2 #

OTP-18887
Related Id(s):

GH-7493, PR-7918

Starting a TLS server without sufficient credentials (certificate or anonymous cipher) would work, but it was impossible to connect to it.

This has been corrected to return an error instead of starting the server.

OTP-18969
Related Id(s):

GH-8058, PR-8256

ASN.1 decoding errors are handled in more places to ensure that errors are returned instead of cause a crash.

OTP-18992
Related Id(s):

GH-8066, PR-8156

Improved error checking on the API functions.

OTP-18606
HIGHLIGHT
 

The ssl client can negotiate and handle certificate status request (OCSP stapling support on the client side).

Thanks to voltone for interop testing and related discussions.

OTP-18665
Related Id(s):

PR-7447

Memory consumption has been reduced and performance increased by refactoring internal data structures and their usage.

OTP-18788
Related Id(s):

PR-7700

Added ssl_crl_cache_api:lookup/2 as an optional -callback attribute.

OTP-18876
Related Id(s):

PR-7475, PR-7898

Key customization support has been extended to allow flexibility for implementers of for instance hardware security modules (HSM) or trusted platform modules (TPM).

OTP-18879

The proc_lib:set_label/1 function is now used to increase observability of ssl processes.

OTP-18884
Related Id(s):

PR-8056

Brainpool elliptic curves are now supported in TLS-1.3.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19025
HIGHLIGHT, POTENTIAL INCOMPATIBILITY
 

For security reasons, the CBC ciphers are now longer included in the list of default ciphers for TLS-1.2.

OTP-19027
Related Id(s):

PR-8255

There is a new cert_policy_opts option to configure certificate policy options for the certificate path validation.

Full runtime dependencies of ssl-11.2

crypto-5.0, erts-15.0, inets-5.10.7, kernel-9.0, public_key-1.15, runtime_tools-1.15.1, stdlib-6.0

stdlib-6.0 #

OTP-18684
Related Id(s):

PR-7481

The specs in module binary has been updated to reflect what is allowed by the documentation.

OTP-18743
Related Id(s):

PR-7607, PR-7628

Several functions in the binary module would accept arguments of the wrong type under certain circumstances. In this release, they now raise an exception when incorrect types are given.

The following functions would accept an invalid pattern if the subject binary was empty or if the {scope,{0,0}} option was given: binary:match/2,3, binary:matches/2,3, binary:replace/3,4, and binary:split/2,3

The call binary:copy(<<1:1>>, 0) would return an empty binary instead of raising an exception. Similarly, calls to binary:part/2,3 attempting to extract 0 bytes at position 0 of a bitstring would return an empty binary instead of raising an exception.

OTP-18784
POTENTIAL INCOMPATIBILITY
 

The documentation for the preprocessor now mentions that defined(Name) can be called in the condition for an -if or -elif directive to test whether Name is the name of a defined macro. (This feature was implemented in OTP 21.)

If a function call in an -if or -elif with a name that is not the name of a guard BIF, there would not be a compilation error, but would instead cause the lines following the directive to be skipped. This has now been changed to be a compilation error.

OTP-18930
Related Id(s):

GH-4992, PR-7993

get_until requests using the I/O protocol now correctly return a binary or list when eof is the last item returned by the callback.

OTP-19029
POTENTIAL INCOMPATIBILITY
 

The error handling the simple_one_for_one supervisor has been enhanced. A transient child returning ignore will no longer cause a crash.

Also, automatic shutdown has been disabled because it does not make sense for this supervisor type. That is was allowed is considered a bug. Therefore, we don’t consider this an incompatible change.

OTP-19073
Related Id(s):

GH-8364, GH-8365, GH-8366, PR-8375

Fix shell expansion to not crash when expanding a map with non-atom keys and to not list zero arity functions when an argument has been given.

OTP-18622
HIGHLIGHT
 

The functions is_equal/2, map/2, and filtermap/2 have been added to the modules sets, ordsets, and gb_sets.

OTP-18648
HIGHLIGHT
 

The compiler now emits nicer error message for function head mismatches. For example, given:

a() -> ok;
a(_) -> error.

Erlang/OTP 26 and earlier would emit a diagnostic similar to:

t.erl:6:1: head mismatch
%    6| a(_) -> error.
%     | ^

while in Erlang/OTP 27 the diagnostic is similar to:

t.erl:6:1: head mismatch: function a with arities 0 and 1 is regarded as two distinct functions. Is the number of arguments incorrect or is the semicolon in a/0 unwanted?
%    6| a(_) -> error.
%     | ^
OTP-18668

zip:create/2,3 will now tolerate POSIX timestamps in the provided file_info records.

OTP-18671
Related Id(s):

PR-7419

The callback function gen_statem:handle_event/4 has been cached in the gen_statem engine to optimize callback call speed.

OTP-18716
Related Id(s):

PR-7534

The type beam_lib:beam/0 is now exported.

OTP-18741
Related Id(s):

PR-7585

The documentation for the binary module has been improved.

OTP-18742
Related Id(s):

PR-7590

binary:replace/3,4 now supports using a fun for supplying the replacement binary.

OTP-18750
HIGHLIGHT, POTENTIAL INCOMPATIBILITY
 

Triple-Quoted Strings has been implemented as per EEP 64. See String in the Reference Manual.

Example:

1> """
   a
   b
   c
   """.
"a\nb\nc"

Adjacent string literals without intervening white space is now a syntax error, to avoid possible confusion with triple-quoted strings. For example:

1> "abc""xyz".
"xyz".
* 1:6: adjacent string literals without intervening white space
OTP-18789
Related Id(s):

PR-7720, PR-8003

The new function proc_lib:set_label/1 can be used to add a descriptive term to any process that does not have a registered name. The name will be shown by tools such as \c:i/0, observer, and it will be included in crash reports produced by processes using gen_server, gen_statem, gen_event, and gen_fsm.

The label for a process can be retrieved by calling proc_lib:get_label/1.

Note that those functions work on any process, not only processes that use proc_lib.

Example:

1> self().
<0.90.0>
2> proc_lib:set_label(my_label).
ok
3> i().
    .
    .
    .
<0.90.0>              erlang:apply/2                        2586    75011    0
my_label              c:pinfo/2                               51
4> proc_lib:get_label(self()).
my_label
OTP-18793
Related Id(s):

PR-7703

-callback attributes has been added to modules sys and erl_error.

OTP-18808
HIGHLIGHT
 

Several new functions that accept funs have been added to module timer.

Functions apply_after/2, apply_interval/2, and apply_repeatedly/2 accept a nullary fun as the second argument, while functions apply_after/3, apply_interval/3, and apply_repeatedly/3 accept an n-ary fun as the second and a list of n arguments for the fun as the third argument.

OTP-18825
HIGHLIGHT
 

Sigils on string literals have been implemented as per EEP 66, that is: binary and string sigils in verbatim and escape characters variants, as well as a default (vanilla) Sigil. All for ordinary strings and for triple-quoted strings (EEP 64). See Sigils in the Reference Manual.

Examples:

1> ~"Björn".
<<"Björn"/utf8>>
2> ~b"Björn".
<<"Björn"/utf8>>
3> ~S"\s*(\w+)".
"\\s*(\\w+)"
4> ~B"\s*(\w+)".
<<"\\s*(\\w+)">>
OTP-18834
Related Id(s):

PR-7675, PR-7816

Functions shell:default_multiline_prompt/1, shell:inverted_space_prompt/1, and shell:prompt_width/1 have been exported to help with custom prompt implementations.

OTP-18846
Related Id(s):

PR-7845

The shell now pages long output from the documentation help command (h(Module)), auto completions and the search command.

OTP-18847
Related Id(s):

PR-7846

The M-h hotkey (Alt/Option-h) now outputs help for the module or function directly before the cursor.

OTP-18848
Related Id(s):

PR-7847

Added support for adding a custom code formatter that formats your multi-line shell commands in your preferred formatting on submission. See shell:format_shell_func/ and shell:erl_pp_format_func/1.

OTP-18852
Related Id(s):

PR-7844

Added shell functions for viewing, forgetting and saving locally defined functions, types and records.

OTP-18865
Related Id(s):

PR-7879

Added string:jaro_similarity/2, which can be used to calculate the similarity between two strings.

OTP-18870
Related Id(s):

PR-7857

The new function ets:update_element/4 is similar to ets:update_element/3, but takes a default tuple as the fourth argument, which will be inserted if no previous record with that key exists.

OTP-18874
Related Id(s):

PR-7745

Added functions to retrieve the next higher or lower key/element from gb_trees and gb_sets, as well as returning iterators that start at given keys/elements.

OTP-18908
Related Id(s):

PR-7957

When the shell built-in function c/1,2 is used to re-compile a module, the current working directory of the original compilation is now added to the include path.

OTP-18914
Related Id(s):

PR-7973

The timer module now uses a private table for its internal state, slightly improving its performance.

OTP-18916
HIGHLIGHT
 

EEP-59 - Documentation Attributes has been implemented.

Documentation attributes can be used to document functions, types, callbacks, and modules. The keyword -moduledoc "Documentation here". is used to document modules, while -doc "Documentation here". can be used on top of functions, types, and callbacks to document them, respectively.

  • Types, callbacks, and function documentation can be set to hidden either via -doc false or -doc hidden. When documentation attributes mark a type as hidden, they will not be part of the documentation.
  • The documentation from moduledoc and doc gets added by default to the binary beam file, following the format of EEP-48.
  • Using the compiler flag warn_missing_doc will raise a warning when -doc attributes are missing in exported functions, types, and callbacks.
  • Using the compiler flag warn_missing_spec_documented will raise a warning when spec attributes are missing in documented functions, types, and callbacks.
  • moduledocs and docs may refer to external files to be embedded, such as -doc {file, "README.md"}., which refers to the file README.md found in the current working directory.
  • The compiler warns about exported functions whose specs refer to hidden types. Thus, there will be warnings when a hidden type (meaning, the type is not part of the documentation) gets used in an exported function.
OTP-18923
HIGHLIGHT
 

New ets functions ets:first_lookup/1, ets:next_lookup/2, ets:prev_lookup/2 and ets:last_lookup/1. Example: ets:next_lookup/1 is equivalent to ets:next/2 followed by ets:lookup/2 with the next key. The new combined functions are more efficient and with guaranteed atomicity.

OTP-18944
HIGHLIGHT
 

The maybe expression is now enabled by default.

To use maybe as an atom, it needs to be single-quoted. Alternatively, the maybe expression can be disabled by disabling the maybe_expr feature. That can be done by placing the following the line at the beginning of an Erlang source file:

-feature(maybe_expr, disable).

Another way to disable the maybe_expr feature is by passing the -disable-feature option to erlc:

erlc -disable-feature maybe_expr some_file.erl
OTP-18951
Related Id(s):

PR-8069

The compiler will now raise a warning when updating record/map literals. As an example, consider this module:

-module(t).
-export([f/0]).
-record(r, {a,b,c}).

f() ->
    #r{a=1}#r{b=2}.

The compiler raises the following warning:

1> c(t).
t.erl:6:12: Warning: expression updates a literal
%    6|     #r{a=1}#r{b=2}.
%     |            ^
OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-18993
Related Id(s):

PR-8048

Optimized ets:foldl and ets:foldr to use new ets:next_lookup. Also made them immune against table renaming.

OTP-19001
Related Id(s):

PR-8164

Windows now supports all functions in math.

OTP-19010
Related Id(s):

PR-8205

m:erl_lint (and by extension the compiler) will now warn for code using deprecated callbacks.

The only callback currenly deprecated is format_status/2 in gen_server, gen_event and gen_statem.

You can use nowarn_deprecated_callback to silence the warning.

OTP-19020
HIGHLIGHT
 

There is a new module json for encoding and decoding JSON.

Both encoding and decoding can be customized. Decoding can be done in a SAX-like fashion and handle multiple documents and streams of data.

Full runtime dependencies of stdlib-6.0

compiler-5.0, crypto-4.5, erts-15.0, kernel-10.0, sasl-3.0

syntax_tools-3.2 #

OTP-18608
Related Id(s):

GH-7266, PR-7267

The epp_dodger module can now handle the maybe and else keywords.

OTP-18805
Related Id(s):

PR-7398

Reverting a #wrapper will no longer throw away changes made to positions/annotations.

OTP-18715
Related Id(s):

PR-7535

The type erl_syntax:annotation_or_location/0 is now exported.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of syntax_tools-3.2

compiler-7.0, erts-9.0, kernel-5.0, stdlib-4.0

tftp-1.2 #

OTP-18787
Related Id(s):

PR-7700

There is a new tftp_logger callback behavior module.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of tftp-1.2

erts-6.0, kernel-6.0, stdlib-5.0

tools-4.0 #

OTP-18860

Dialyzer warnings due to type specs added in dbg have been eliminated.

OTP-18998
Related Id(s):

GH-8159, PR-8182

In Erlang/OTP 26, doing a cover analysis on the line level would return multiple entries for lines on which multiple functions were defined.

For example, consider this module:

-module(foo).
-export([bar/0, baz/0]).

bar() -> ok. baz() -> not_ok.

{% raw %}

In Erlang/OTP 26, analysing on the line level would return two entries for line 4:

1> cover:compile_module(foo).
{ok,foo}
2> foo:bar().
ok
3> cover:analyse(foo, coverage, line).
{ok,[{{foo,4},{1,0}},{{foo,4},{0,1}}]}
4> cover:analyse(foo, calls, line).
{ok,[{{foo,4},1},{{foo,4},0}]}

In Erlang/OTP 27, there will only be a single entry for line 4:

1> cover:compile_module(foo).
{ok,foo}
2> foo:bar().
ok
3> cover:analyse(foo, coverage, line).
{ok,[{{foo,4},{1,0}}]}
4> cover:analyse(foo, calls, line).
{ok,[{{foo,4},1}]}

{% endraw %}

OTP-19026
Related Id(s):

PR-8155

Fixed align command in emacs mode.

OTP-18750
HIGHLIGHT, POTENTIAL INCOMPATIBILITY
 

Triple-Quoted Strings has been implemented as per EEP 64. See String in the Reference Manual.

Example:

1> """
   a
   b
   c
   """.
"a\nb\nc"

Adjacent string literals without intervening white space is now a syntax error, to avoid possible confusion with triple-quoted strings. For example:

1> "abc""xyz".
"xyz".
* 1:6: adjacent string literals without intervening white space
OTP-18756
HIGHLIGHT
 

There is a new tool tprof, which combines the functionality of eprof and cprof under one interface and adds heap profiling. It also has functionality to help with profiling process hierarchies.

Example:

1> tprof:profile(lists, seq, [1, 16], #{type => call_memory}).

****** Process <0.92.0>  --  100.00% of total ***
FUNCTION          CALLS  WORDS  PER CALL  [     %]
lists:seq_loop/3      5     32      6.40  [100.00]
                            32            [ 100.0]
ok
OTP-18856
HIGHLIGHT
 

Native coverage support has been implemented in the JIT. It will automatically be used by the cover tool to reduce the execution overhead when running cover-compiled code.

There are also new APIs to support native coverage without using the cover tool.

To instrument code for native coverage it must be compiled with the line_coverage option.

To enable native coverage in the runtime system, start it like so:

$ erl +JPcover true

There are also the following new functions for supporting native coverage:

  • code:coverage_support/0
  • code:get_coverage/2
  • code:reset_coverage/1
  • code:get_coverage_mode/0
  • code:get_coverage_mode/1
  • code:set_coverage_mode/1
OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

OTP-19080
Related Id(s):

PR-8288

Improved the align command in emacs mode.

Full runtime dependencies of tools-4.0

compiler-8.5, erts-15.0, erts-15.0, kernel-10.0, runtime_tools-2.1, stdlib-6.0

wx-2.4.2 #

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of wx-2.4.2

erts-12.0, kernel-8.0, stdlib-5.0

xmerl-2.0 #

OTP-19079
POTENTIAL INCOMPATIBILITY
 

Some default values in Xmerl has been changed to avoid XML External Entity (XXE) vulnerabilities if you’re parsing untrusted XML.

xmerl_scan: the default value for allow_entities has changed to false. xmerl_sax_parser: the default value for external_entities has changed to none.

OTP-19086
Related Id(s):

GH-8452

An event state in xmerl_sax_parser which was updated in the event callback for a startEntity was not saved.

OTP-18913

Function specifications and types have been added to all public API functions.

OTP-18922
Related Id(s):

PR-7942

As an alternative to xmerl_xml, a new export module xmerl_xml_indent that provides out-of-the box indented output has been added.

OTP-18955
HIGHLIGHT
 

The documentation has been migrated to use Markdown and ExDoc.

Full runtime dependencies of xmerl-2.0

erts-6.0, kernel-3.0, stdlib-2.5

Thanks To #

Alexander Clouter, Andrea Leopardi, Angelo Lakra, Anshul Mittal (WhatsApp), Anupama Singh, Artem Solomatin, Benjamin Philip, chiroptical, Christian Flicker, Fabian N.C. van ‘t Hooft, Frej Drejhammar, Gilbert, Guilherme Andrade, Gustaw Lippa, Ildar Khizbulin, Ilya Klyuchnikov, Ivan Sokolov, Jakub Witczak, Jan Uhlig, jdamanalo, jianhui, João Henrique Ferreira de Freitas, Johannes Christ, Jonatan Männchen, Jonathan Arnett, José Valim, Jurek Michal-AMJ018, lexprfuncall, LJZN, Luca Succi, Łukasz Niemier, Marcelino Alberdi Pereira, Maria Scott, Marko Mindek, Matthew Pope, Maxim Fedorov, Max Nordlund kivra, M-I, Michael Davis, Michal Jurek, Michal Kuratczyk, Michał Muskała, Nelson Vides, neo, Nikolay Amiantov, Paul Guyot, Paulo F. Oliveira, Richard Carlsson, Roberto Aloi, Robin Morisset, Ryota Kinukawa, Sacha, Sergey Yelin, Takeru Ohta, Tomas Abrahamsson, William Fank Thomé, WLSF, yastanotheruser, zeyun chen, Zeyu Zhang