{ "content": [ { "type": "text", "text": "# perl5380delta (man)\n\n## NAME\n\nperl5380delta - what is new for perl v5.38.0\n\n## DESCRIPTION\n\nThis document describes differences between the 5.36.0 release and the 5.38.0 release.\n\n## Sections\n\n- **NAME**\n- **DESCRIPTION**\n- **Core Enhancements** (13 subsections)\n- **Incompatible Changes** (5 subsections)\n- **Deprecations** (2 subsections)\n- **Performance Enhancements**\n- **Modules and Pragmata** (1 subsections)\n- **Documentation** (2 subsections)\n- **Diagnostics** (2 subsections)\n- **Configuration and Compilation**\n- **Testing**\n- **Platform Support** (2 subsections)\n- **Internal Changes**\n- **Selected Bug Fixes**\n- **Acknowledgements**\n- **Reporting Bugs**\n- **Give Thanks**\n- **SEE ALSO**\n\nUse structuredContent.sections for detailed options, examples, and full documentation.\n" } ], "structuredContent": { "command": "perl5380delta", "section": "", "mode": "man", "summary": "perl5380delta - what is new for perl v5.38.0", "synopsis": null, "tldr_summary": null, "tldr_examples": [], "tldr_source": null, "flags": [], "examples": [], "see_also": [], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "DESCRIPTION", "lines": 2, "subsections": [] }, { "name": "Core Enhancements", "lines": 1, "subsections": [ { "name": "New \"class\" Feature", "lines": 24 }, { "name": "Unicode 15.0 is supported", "lines": 2 }, { "name": "Deprecation warnings now have specific subcategories", "lines": 29 }, { "name": "%{^HOOK} API introduced", "lines": 29 }, { "name": "Defined-or and logical-or assignment default expressions in signatures", "lines": 5 }, { "name": "@INC Hook Enhancements and $INC and INCDIR", "lines": 23 }, { "name": "Forbidden control flow out of \"defer\" or \"finally\" now detected at compile-time", "lines": 10 }, { "name": "Optimistic Eval in Patterns", "lines": 10 }, { "name": "REG_INF has been raised from 65,536 to 2,147,483,647", "lines": 4 }, { "name": "New API functions optimize_optree and finalize_optree", "lines": 10 }, { "name": "Some \"goto\"s are now permitted in \"defer\" and \"finally\" blocks", "lines": 14 }, { "name": "New regexp variable ${^LAST_SUCCESSFUL_PATTERN}", "lines": 17 }, { "name": "Locale category LC_NAME now supported on participating platforms", "lines": 3 } ] }, { "name": "Incompatible Changes", "lines": 1, "subsections": [ { "name": "readline() no longer clears the stream error and eof flags", "lines": 27 }, { "name": "\"INIT\" blocks no longer run after an exit() in \"BEGIN\"", "lines": 9 }, { "name": "Syntax errors no longer produce \"phantom error messages\"", "lines": 12 }, { "name": "utf8::upgrade()", "lines": 3 }, { "name": "Changes to \"thread-safe\" locales", "lines": 21 } ] }, { "name": "Deprecations", "lines": 1, "subsections": [ { "name": "Use of \"'\" as a package name separator is deprecated", "lines": 4 }, { "name": "Switch and Smart Match operator", "lines": 10 } ] }, { "name": "Performance Enhancements", "lines": 10, "subsections": [] }, { "name": "Modules and Pragmata", "lines": 1, "subsections": [ { "name": "Updated Modules and Pragmata", "lines": 211 } ] }, { "name": "Documentation", "lines": 1, "subsections": [ { "name": "New Documentation", "lines": 8 }, { "name": "Changes to Existing Documentation", "lines": 101 } ] }, { "name": "Diagnostics", "lines": 3, "subsections": [ { "name": "New Diagnostics", "lines": 202 }, { "name": "Changes to Existing Diagnostics", "lines": 128 } ] }, { "name": "Configuration and Compilation", "lines": 27, "subsections": [] }, { "name": "Testing", "lines": 7, "subsections": [] }, { "name": "Platform Support", "lines": 1, "subsections": [ { "name": "Discontinued Platforms", "lines": 5 }, { "name": "Platform-Specific Notes", "lines": 51 } ] }, { "name": "Internal Changes", "lines": 178, "subsections": [] }, { "name": "Selected Bug Fixes", "lines": 141, "subsections": [] }, { "name": "Acknowledgements", "lines": 38, "subsections": [] }, { "name": "Reporting Bugs", "lines": 12, "subsections": [] }, { "name": "Give Thanks", "lines": 7, "subsections": [] }, { "name": "SEE ALSO", "lines": 9, "subsections": [] } ], "sections": { "NAME": { "content": "perl5380delta - what is new for perl v5.38.0\n", "subsections": [] }, "DESCRIPTION": { "content": "This document describes differences between the 5.36.0 release and the 5.38.0 release.\n", "subsections": [] }, "Core Enhancements": { "content": "", "subsections": [ { "name": "New \"class\" Feature", "content": "A new experimental syntax is now available for defining object classes, where per-instance\ndata is stored in \"field\" variables that behave like lexicals.\n\nuse feature 'class';\n\nclass Point\n{\nfield $x;\nfield $y;\n\nmethod zero { $x = $y = 0; }\n}\n\nThis is described in more detail in perlclass. Notes on the internals of its implementation\nand other related details can be found in perlclassguts.\n\nThis remains a new and experimental feature, and is very much still under development. It\nwill be the subject of much further addition, refinement and alteration in future releases.\nAs it is experimental, it yields warnings in the \"experimental::class\" category. These can\nbe silenced by a \"no warnings\" statement.\n\nuse feature 'class';\nno warnings 'experimental::class';\n" }, { "name": "Unicode 15.0 is supported", "content": "See for details.\n" }, { "name": "Deprecation warnings now have specific subcategories", "content": "All deprecation warnings now have their own specific deprecation category which can be\ndisabled individually. You can see a list of all deprecated features in perldeprecation, and\nin warnings. The following list is from warnings:\n\n+- deprecated ----+\n| |\n| +- deprecated::apostropheaspackageseparator\n| |\n| +- deprecated::delimiterwillbepaired\n| |\n| +- deprecated::dotininc\n| |\n| +- deprecated::gotoconstruct\n| |\n| +- deprecated::smartmatch\n| |\n| +- deprecated::unicodepropertyname\n| |\n| +- deprecated::versiondowngrade\n\nIt is still possible to disable all deprecation warnings in a single statement with\n\nno warnings 'deprecated';\n\nbut now is possible to have a finer grained control. As has historically been the case these\nwarnings are automatically enabled with\n\nuse warnings;\n" }, { "name": "%{^HOOK} API introduced", "content": "For various reasons it can be difficult to create subroutine wrappers for some of perls\nkeywords. Any keyword which has an undefined prototype simply cannot be wrapped with a\nsubroutine, and some keywords which perl permits to be wrapped are in practice very tricky to\nwrap. For example \"require\" is tricky to wrap, it is possible but doing so changes the stack\ndepth, and the standard methods of exporting assume that they will be exporting to a package\nat certain stack depth up the stack, and the wrapper will thus change where functions are\nexported to unless implemented with a great deal of care. This can be very awkward to deal\nwith.\n\nAccordingly we have introduced a new hash called \"%{^HOOK}\" which is intended to facilitate\nsuch cases. When a keyword supports any kind of special hook then the hook will live in this\nnew hash. Hooks in this hash will be named after the function they are called by, followed by\ntwo underbars and then the phase they are executed in, currently either before or after the\nkeyword is executed.\n\nIn this initial release we support two hooks \"requirebefore\" and \"requireafter\". These\nare provided to make it easier to perform tasks before and after a require statement.\n\nSee perlvar for more details.\n\nPERLRANDSEED\nAdded a new environment variable \"PERLRANDSEED\" which can be used to cause a perl program\nwhich uses \"rand\" without using srand() explicitly or which uses srand() with no arguments to\nbe repeatable. See perlrun. This feature can be disabled at compile time by passing\n\n-Accflags=-DNOPERLRANDSEED\n\nto Configure during the build process.\n" }, { "name": "Defined-or and logical-or assignment default expressions in signatures", "content": "The default expression for a subroutine signature parameter can now be assigned using the\n\"//=\" or \"||=\" operators, to apply the defaults whenever the caller provided an undefined or\nfalse value (respectively), rather than simply when the parameter is missing entirely. For\nmore detail see the documentation in perlsub.\n" }, { "name": "@INC Hook Enhancements and $INC and INCDIR", "content": "The internals for @INC hooks have been hardened to handle various edge cases and should no\nlonger segfault or throw assert failures when hooks modify @INC during a require operation.\nAs part of this we now ensure that any given hook is executed at most once during a require\ncall, and that any duplicate directories do not trigger additional directory probes.\n\nTo provide developers more control over dynamic module lookup, a new hook method \"INCDIR\" is\nnow supported. An object supporting this method may be injected into the @INC array, and when\nit is encountered in the module search process it will be executed, just like how INC hooks\nare executed, and its return value used as a list of directories to search for the module.\nReturning an empty list acts as a no-op. Note that since any references returned by this hook\nwill be stringified and used as strings, you may not return a hook to be executed later via\nthis API.\n\nWhen an @INC hook (either \"INC\" or \"INCDIR\") is called during require, the $INC variable will\nbe localized to be the value of the index of @INC that the hook came from. If the hook wishes\nto override what the \"next\" index in @INC should be it may update $INC to be one less than\nthe desired index (\"undef\" is equivalent to -1). This allows an @INC hook to completely\nrewrite the @INC array and have perl restart its directory probes from the beginning of @INC.\n\nBlessed CODE references in @INC that do not support the \"INC\" or \"INCDIR\" methods will no\nlonger trigger an exception, and instead will be treated the same as unblessed coderefs are,\nand executed as though they were an \"INC\" hook.\n" }, { "name": "Forbidden control flow out of \"defer\" or \"finally\" now detected at compile-time", "content": "It is forbidden to attempt to leave a \"defer\" or \"finally\" block by means of control flow\nsuch as \"return\" or \"goto\". Previous versions of perl could only detect this when actually\nattempted at runtime.\n\nThis version of perl adds compile-time detection for many cases that can be statically\ndetermined. This may mean that code which compiled successfully on a previous version of perl\nis now reported as a compile-time error with this one. This only happens in cases where it\nwould have been an error to actually execute the code anyway; the error simply happens at an\nearlier time.\n" }, { "name": "Optimistic Eval in Patterns", "content": "The use of \"(?{ ... })\" and \"(??{ ... })\" in a pattern disables various optimisations\nglobally in that pattern. This may or may not be desired by the programmer. This release adds\nthe \"(*{ ... })\" equivalent. The only difference is that it does not and will never disable\nany optimisations in the regex engine. This may make it more unstable in the sense that it\nmay be called more or less times in the future, however the number of times it executes will\ntruly match how the regex engine functions. For example, certain types of optimisation are\ndisabled when \"(?{ ... })\" is included in a pattern, so that patterns which are O(N) in\nnormal use become O(N*N) with a \"(?{ ... })\" pattern in them. Switching to \"(*{ ... })\" means\nthe pattern will stay O(N).\n" }, { "name": "REG_INF has been raised from 65,536 to 2,147,483,647", "content": "Many regex quantifiers used to be limited to \"U16MAX\" in the past, but are now limited to\n\"I32MAX\", thus it is now possible to write \"/(?:word){1000000}/\" for example. Note that\ndoing so may cause the regex engine to run longer and use more memory.\n" }, { "name": "New API functions optimize_optree and finalize_optree", "content": "There are two new API functions for operating on optree fragments, ensuring you can invoke\nthe required parts of the optree-generation process that might otherwise not get invoked\n(e.g. when creating a custom LOGOP). To get access to these functions, you first need to set\na \"#define\" to opt-in to using these functions.\n\n#define PERLUSEVOLATILEAPI\n\nThese functions are closely tied to the internals of how the interpreter works, and could be\naltered or removed at any time if other internal changes make that necessary.\n" }, { "name": "Some \"goto\"s are now permitted in \"defer\" and \"finally\" blocks", "content": "Perl version 5.36.0 added \"defer\" blocks and permitted the \"finally\" keyword to also add\nsimilar behaviour to \"try\"/\"catch\" syntax. These did not permit any \"goto\" expression within\nthe body, as it could have caused control flow to jump out of the block. Now, some \"goto\"\nexpressions are allowed, if they have a constant target label, and that label is found within\nthe block.\n\nuse feature 'defer';\n\ndefer {\ngoto LABEL;\nprint \"This does not execute\\n\";\nLABEL: print \"This does\\n\";\n}\n" }, { "name": "New regexp variable ${^LAST_SUCCESSFUL_PATTERN}", "content": "This allows access to the last succesful pattern that matched in the current scope. Many\naspects of the regex engine refer to the \"last successful pattern\". The empty pattern reuses\nit, and all of the magic regex vars relate to it. This allows access to its pattern. The\nfollowing code\n\nif (m/foo/ || m/bar/) {\ns//PQR/;\n}\n\ncan be rewritten as follows\n\nif (m/foo/ || m/bar/) {\ns/${^LASTSUCCESSFULPATTERN}/PQR/;\n}\n\nand it will do the exactly same thing.\n" }, { "name": "Locale category LC_NAME now supported on participating platforms", "content": "On platforms that have the GNU extension \"LCNAME\" category, you may now use it as the\ncategory parameter to \"setlocale\" in POSIX to set and query its locale.\n" } ] }, "Incompatible Changes": { "content": "", "subsections": [ { "name": "readline() no longer clears the stream error and eof flags", "content": "readline(), also spelled \"<>\", would clear the handle's error and eof flags after an error\noccurred on the stream.\n\nIn nearly all cases this clear is no longer done, so the error and eof flags now properly\nreflect the status of the stream after readline().\n\nSince the error flag is no longer cleared calling close() on the stream may fail and if the\nstream was not explicitly closed, the implicit close of the stream may produce a warning.\n\nThis has resulted in two main types of problems in downstream CPAN modules, and these may\nalso occur in your code:\n\n• If your code reads to end of file, and then rebinds the handle to a new file descriptor,\npreviously since the eof flag wasn't set you could continue to read from the stream. You\nnow need to clear the eof flag yourself with \"$handle->clearerr()\" to continue reading.\n\n• If your code encounters an error on the stream while reading with readline() you will\nneed to call \"$handle->clearerr\" to continue reading. The one case this occurred the\nunderlying file descriptor was marked non-blocking, so the read() system call was failing\nwith \"EAGAIN\", which resulted in the error flag being set on the stream.\n\nThe only case where error and eof flags continue to cleared on error is when reading from the\nchild process for glob() in miniperl. This allows it to correctly report errors from the\nchild process on close(). This is unlikely to be an issue during normal perl development.\n\n[GH #20060 ]\n" }, { "name": "\"INIT\" blocks no longer run after an exit() in \"BEGIN\"", "content": "\"INIT\" blocks will no longer run after an exit() performed inside of a \"BEGIN\". This means\nthat the combination of the \"-v\" option and the \"-c\" option no longer executes a compile\ncheck as well as showing the perl version. The \"-v\" option executes an exit(0) after printing\nthe version information inside of a \"BEGIN\" block, and the \"-c\" check is implemented by using\n\"INIT\" hooks, resulting in the \"-v\" option taking precedence.\n\n[GH #1537 ] [GH #20181\n]\n" }, { "name": "Syntax errors no longer produce \"phantom error messages\"", "content": "Generally perl will continue parsing the source code even after encountering a compile error.\nIn many cases this is helpful, for instance with misspelled variable names it is helpful to\nshow as many examples of the error as possible. But in the case of syntax errors continuing\noften produces bizarre error messages and may even cause segmentation faults during the\ncompile process. In this release the compiler will halt at the first syntax error\nencountered. This means that any code expecting to see the specific error messages we used to\nproduce will be broken. The error that is emitted will be one of the diagnostics that used to\nbe produced, but in some cases some messages that used to be produced will no longer be\ndisplayed.\n\nSee \"Changes to Existing Diagnostics\" for more details.\n" }, { "name": "utf8::upgrade()", "content": "Starting in this release, if the input string is \"undef\", it remains \"undef\". Previously it\nwould be changed into a defined, zero-length string.\n" }, { "name": "Changes to \"thread-safe\" locales", "content": "Perl 5.28 introduced \"thread-safe\" locales on systems that supported them, namely modern\nWindows, and systems supporting POSIX 2008 locale operations. These systems accomplish this\nby having per-thread locales, while continuing to support the older global locale operations\nfor code that doesn't take the steps necessary to use the newer per-thread ones.\n\nIt turns out that some POSIX 2008 platforms have or have had buggy implementations, which\nforced perl to not use them. The \"${^SAFELOCALES}\" scalar variable contains 0 or 1 to\nindicate whether or not the current platform is considered by perl to have a working thread-\nsafe implementation. Some implementations have been fixed already, but FreeBSD and Cygwin\nhave been newly discovered to be sufficiently buggy that the thread-safe operations are no\nlonger used by perl, starting in this release. Hence, \"${^SAFELOCALES}\" is now 0 for them.\nOlder versions of perl can be configured to avoid these buggy implementations by adding the\nConfigure option \"-DNOPOSIX2008LOCALE\".\n\nAnd v5.38 fixes a bug in all previous perls that led to locales not being fully thread-safe.\nThe first thread that finishes caused the main thread (named \"thread0\") to revert to the\nglobal locale in effect at startup, discarding whatever the thread's locale had been\npreviously set to. If any other thread had switched to the global locale by calling\nswitchtogloballocale() in XS code, those threads would all share the global locale, and\n\"thread0\" would not be thread-safe.\n" } ] }, "Deprecations": { "content": "", "subsections": [ { "name": "Use of \"'\" as a package name separator is deprecated", "content": "Using \"'\" as package separator in a variable named in a double-quoted string has warned since\n5.28. It is now deprecated in both string interpolation and non-interpolated contexts, and\nwill be removed in Perl 5.42.\n" }, { "name": "Switch and Smart Match operator", "content": "The \"switch\" feature and the smartmatch operator, \"~~\", were introduced in v5.10. Their\nbehavior was significantly changed in v5.10.1. When the \"experiment\" system was added in\nv5.18.0, switch and smartmatch were retroactively declared experimental. Over the years,\nproposals to fix or supplement the features have come and gone.\n\nIn v5.38.0, we are declaring the experiment a failure. Some future system may take the\nconceptual place of smartmatch, but it has not yet been designed or built.\n\nThese features will be entirely removed from perl in v5.42.0.\n" } ] }, "Performance Enhancements": { "content": "• Additional optree optimizations for common OP patterns. For example, multiple simple OPs\nreplaced by a single streamlined OP, so as to be more efficient at runtime. [GH #19943\n], [GH #20063\n], [GH #20077\n].\n\n• Creating an anonymous sub no longer generates an \"srefgen\" op, the reference generation\nis now done in the \"anoncode\" or \"anonconst\" op, saving runtime. [GH #20290\n]\n", "subsections": [] }, "Modules and Pragmata": { "content": "", "subsections": [ { "name": "Updated Modules and Pragmata", "content": "• Added the istainted() builtin function. [GH #19854\n]\n\n• Added the exportlexically() builtin function as per PPC 0020\n. [GH #19895\n]\n\n• Support for PPC 0018 , \"use feature \"moduletrue\";\" has been added to the default feature bundle for\nv5.38 and later. It may also be used explicitly. When enabled inside of a module the\nmodule does not need to return true explicitly, and in fact the return will be forced to\na simple true value regardless of what it originally was.\n\n• Attribute::Handlers has been upgraded from version 1.02 to 1.03.\n\n• attributes has been upgraded from version 0.34 to 0.35.\n\n• autodie has been upgraded from version 2.34 to 2.36.\n\n• B has been upgraded from version 1.83 to 1.88.\n\n• B::Concise has been upgraded from version 1.006 to 1.007.\n\n• B::Deparse has been upgraded from version 1.64 to 1.74.\n\n• Benchmark has been upgraded from version 1.23 to 1.24.\n\n• bignum has been upgraded from version 0.65 to 0.66.\n\n• Carp has been upgraded from version 1.52 to 1.54.\n\n• Class::Struct has been upgraded from version 0.66 to 0.68.\n\n• Compress::Raw::Bzip2 has been upgraded from version 2.103 to 2.204001.\n\n• Compress::Raw::Zlib has been upgraded from version 2.105 to 2.204001.\n\n• Config::Perl::V has been upgraded from version 0.33 to 0.36.\n\n• CPAN has been upgraded from version 2.33 to 2.36.\n\n• Data::Dumper has been upgraded from version 2.184 to 2.188.\n\n• DBFile has been upgraded from version 1.857 to 1.858.\n\n• Devel::Peek has been upgraded from version 1.32 to 1.33.\n\n• Devel::PPPort has been upgraded from version 3.68 to 3.71.\n\n• Digest::MD5 has been upgraded from version 2.58 to 2.5801.\n\n• Digest::SHA has been upgraded from version 6.02 to 6.04.\n\n• DynaLoader has been upgraded from version 1.52 to 1.54.\n\n• Encode has been upgraded from version 3.17 to 3.19.\n\n• encoding::warnings has been upgraded from version 0.13 to 0.14.\n\n• Env has been upgraded from version 1.05 to 1.06.\n\n• Errno has been upgraded from version 1.36 to 1.37.\n\n• experimental has been upgraded from version 0.028 to 0.031.\n\n• ExtUtils::CBuilder has been upgraded from version 0.280236 to 0.280238.\n\n• ExtUtils::Install has been upgraded from version 2.20 to 2.22.\n\n• ExtUtils::MakeMaker has been upgraded from version 7.64 to 7.70.\n\n• ExtUtils::Miniperl has been upgraded from version 1.11 to 1.13.\n\n• ExtUtils::ParseXS has been upgraded from version 3.45 to 3.51.\n\n• ExtUtils::PL2Bat has been upgraded from version 0.004 to 0.005.\n\n• ExtUtils::Typemaps has been upgraded from version 3.45 to 3.51.\n\n• feature has been upgraded from version 1.72 to 1.82.\n\n• File::Basename has been upgraded from version 2.85 to 2.86.\n\n• File::Copy has been upgraded from version 2.39 to 2.41.\n\n• File::Find has been upgraded from version 1.40 to 1.43.\n\n• File::Glob has been upgraded from version 1.37 to 1.40.\n\n• File::Spec has been upgraded from version 3.84 to 3.89.\n\n• File::stat has been upgraded from version 1.12 to 1.13.\n\n• FileHandle has been upgraded from version 2.03 to 2.05.\n\n• Filter::Util::Call has been upgraded from version 1.60 to 1.64.\n\n• GDBMFile has been upgraded from version 1.23 to 1.24.\n\n• Getopt::Long has been upgraded from version 2.52 to 2.54.\n\n• Hash::Util has been upgraded from version 0.28 to 0.30.\n\n• HTTP::Tiny has been upgraded from version 0.080 to 0.083.\n\n• I18N::Langinfo has been upgraded from version 0.21 to 0.22.\n\n• IO has been upgraded from version 1.50 to 1.52.\n\n• IO-Compress has been upgraded from version 2.106 to 2.204.\n\n• IO::Socket::IP has been upgraded from version 0.41 to 0.4101.\n\nOn DragonflyBSD, detect setsockopt() not actually clearing \"IPV6V6ONLY\" even when\nsetsockopt() returns success. [cpan #148293\n]\n\n• IO::Zlib has been upgraded from version 1.11 to 1.14.\n\n• JSON::PP has been upgraded from version 4.07 to 4.16.\n\n• libnet has been upgraded from version 3.14 to 3.15.\n\n• Locale::Maketext has been upgraded from version 1.31 to 1.33.\n\n• Math::BigInt has been upgraded from version 1.999830 to 1.999837.\n\n• Math::BigInt::FastCalc has been upgraded from version 0.5012 to 0.5013.\n\n• Math::BigRat has been upgraded from version 0.2621 to 0.2624.\n\n• Math::Complex has been upgraded from version 1.5902 to 1.62.\n\n• Memoize has been upgraded from version 1.0301 to 1.16.\n\n• MIME::Base64 has been upgraded from version 3.16 to 3.1601.\n\n• Module::CoreList has been upgraded from version 5.20220520 to 5.20230520.\n\n• mro has been upgraded from version 1.26 to 1.28.\n\n• NDBMFile has been upgraded from version 1.15 to 1.16.\n\n• Net::Ping has been upgraded from version 2.74 to 2.76.\n\n• ODBMFile has been upgraded from version 1.17 to 1.18.\n\n• Opcode has been upgraded from version 1.57 to 1.64.\n\n• overload has been upgraded from version 1.35 to 1.37.\n\n• parent has been upgraded from version 0.238 to 0.241.\n\n• PerlIO::via::QuotedPrint has been upgraded from version 0.09 to 0.10.\n\n• Pod::Checker has been upgraded from version 1.74 to 1.75.\n\n• Pod::Html has been upgraded from version 1.33 to 1.34.\n\n• Pod::Usage has been upgraded from version 2.01 to 2.03.\n\n• podlators has been upgraded from version 4.14 to 5.01.\n\n• POSIX has been upgraded from version 2.03 to 2.13.\n\n• re has been upgraded from version 0.43 to 0.44.\n\n• Safe has been upgraded from version 2.43 to 2.44.\n\n• Scalar::Util has been upgraded from version 1.62 to 1.63.\n\n• SDBMFile has been upgraded from version 1.15 to 1.17.\n\n• Socket has been upgraded from version 2.033 to 2.036.\n\n• Storable has been upgraded from version 3.26 to 3.32.\n\n• Sys::Hostname has been upgraded from version 1.24 to 1.25.\n\n• Term::Cap has been upgraded from version 1.17 to 1.18.\n\n• Test::Simple has been upgraded from version 1.302190 to 1.302194.\n\n• Text::Balanced has been upgraded from version 2.04 to 2.06.\n\n• threads has been upgraded from version 2.27 to 2.36.\n\n• threads::shared has been upgraded from version 1.64 to 1.68.\n\n• Tie::File has been upgraded from version 1.06 to 1.07.\n\n• Time::HiRes has been upgraded from version 1.9770 to 1.9775.\n\n• Time::Piece has been upgraded from version 1.3401 to 1.340101.\n\n• Unicode::Normalize has been upgraded from version 1.31 to 1.32.\n\n• UNIVERSAL has been upgraded from version 1.14 to 1.15.\n\n• User::grent has been upgraded from version 1.03 to 1.04.\n\n• User::pwent has been upgraded from version 1.01 to 1.02.\n\n• utf8 has been upgraded from version 1.24 to 1.25.\n\n• warnings has been upgraded from version 1.58 to 1.65.\n\n• XS::APItest has been upgraded from version 1.22 to 1.32.\n\n• XSLoader has been upgraded from version 0.31 to 0.32.\n" } ] }, "Documentation": { "content": "", "subsections": [ { "name": "New Documentation", "content": "perlclass\n\nDescribes the new \"class\" feature.\n\nperlclassguts\n\nDescribes the internals of the new \"class\" feature.\n" }, { "name": "Changes to Existing Documentation", "content": "We have attempted to update the documentation to reflect the changes listed in this document.\nIf you find any we have missed, open an issue at .\n\nAdditionally, the following selected changes have been made:\n\nperlapi\n\n• Documented \"hvksplit\"\n\n• Documented \"hvnameset\"\n\n• \"hvstore\" and \"hvstores\" documentation have been greatly improved.\n\n• Documented \"gvautoloadpv\"\n\n• Documented \"gvautoloadpvn\"\n\n• Documented \"gvautoloadsv\"\n\n• Documented \"gvnameset\"\n\n• Documented \"startsubparse\"\n\n• Documented \"SVCHECKTHINKFIRSTCOWDROP\"\n\n• Documented \"SVCHECKTHINKFIRST\"\n\n• Documented \"SvPVshrinktocur\"\n\n• Documented \"saveaelem\"\n\n• Documented \"saveaelemflags\"\n\n• Documented \"savehelem\"\n\n• Documented \"savehelemflags\"\n\nperldeprecation\n\n• Added information about unscheduled deprecations and their categories.\n\n• Added category information for existing scheduled deprecations.\n\n• Added smartmatch and apostrophe as a package separator deprecation data.\n\nperlintern\n\n• Documented \"savepushptr\"\n\n• Documented \"savescalarat\"\n\n• Entries have been added to perlguts for the new \"newAVallocx\", \"newAVallocxz\" and\n*simple functions.\n\n• References to the now-defunct PrePAN service have been removed from perlcommunity and\nperlmodstyle.\n\n• A section on symbol naming has been added to perlhacktips.\n\n• perlexperiment has been edited to properly reference the warning categories for the defer\nblock modifier and extra paired delimiters for quote-like operators.\n\nperlexperiment\n\n• Smartmatch has been moved from experimental status to deprecated status. Unfortunately\nthe experiment did not work out.\n\nperlfunc\n\n• Some wording improvements have been made for the \"ucfirst\", \"push\", \"unshift\" and \"bless\"\nfunctions, as well as additional examples added.\n\nperlhacktips\n\n• A new section, \"Writing safer macros\" in perlhacktips has been added to discuss pitfalls\nand solutions to using C macros in C and XS code.\n\n• A new section, \"Choosing good symbol names\" in perlhacktips, has been added to discuss\nunexpected gotchas with names.\n\nperlop\n\n• Document the behavior of matching the empty pattern better and specify its relationship\nto the new \"${^LASTSUCCESSFULPATTERN}\" properly.\n\nperlvar\n\n• Added a section on \"Scoping Rules of Regex Variables\", and other wording improvements\nmade throughout.\n\n• Added information on the new \"%{^HOOK}\" interface, and the new \"requirebefore\" and\n\"requireafter\" hooks which it exposes.\n\n• Correct information on the regex variables \"${^PREMATCH}\", \"${^MATCH}\" and\n\"${^POSTMATCH}\", all of which were incorrectly documented due to an oversight.\nSpecifically they only work properly after a regex operation that used the /p modifier to\nenable them.\n\n• Added information on the new regex variable \"${^LASTSUCCESSFULPATTERN}\", which\nrepresents the pattern of the last successful regex match in scope.\n" } ] }, "Diagnostics": { "content": "The following additions or changes have been made to diagnostic output, including warnings\nand fatal error messages. For the complete list of diagnostic messages, see perldiag.\n", "subsections": [ { "name": "New Diagnostics", "content": "New Errors\n\n• A new syntax error has been added for the error that a \"catch\" block does not have its\nrequired variable declaration. See catch block requires a (VAR)\n\n• Too many nested BEGIN blocks, maximum of %d allowed\n\n• Execution of %s aborted due to compilation errors.\n\n• Can't locate object method \"INC\", nor \"INCDIR\" nor string overload via package \"%s\" %s in\n@INC\n\n• Attempt to bless into a class\n\n(F) You are attempting to call \"bless\" with a package name that is a new-style \"class\".\nThis is not necessary, as instances created by the constructor are already in the correct\nclass. Instances cannot be created by other means, such as \"bless\".\n\n• Cannot assign :param(%s) to field %s because that name is already in use\n\n(F) An attempt was made to apply a parameter name to a field, when the name is already\nbeing used by another field in the same class, or one of its parent classes. This would\ncause a name clash so is not allowed.\n\n• Cannot create class %s as it already has a non-empty @ISA\n\n(F) An attempt was made to create a class out of a package that already has an @ISA\narray, and the array is not empty. This is not permitted, as it would lead to a class\nwith inconsistent inheritance.\n\n• Cannot invoke a method of \"%s\" on an instance of \"%s\"\n\n(F) You tried to directly call a \"method\" subroutine of one class by passing in a value\nthat is an instance of a different class. This is not permitted, as the method would not\nhave access to the correct instance fields.\n\n• Cannot invoke method on a non-instance\n\n(F) You tried to directly call a \"method\" subroutine of a class by passing in a value\nthat is not an instance of that class. This is not permitted, as the method would not\nthen have access to its instance fields.\n\n• Cannot '%s' outside of a 'class'\n\n(F) You attempted to use one of the keywords that only makes sense inside a \"class\"\ndefinition, at a location that is not inside such a class.\n\n• Cannot reopen existing class \"%s\"\n\n(F) You tried to begin a \"class\" definition for a class that already exists. A class may\nonly have one definition block.\n\n• Can't bless an object reference\n\n(F) You attempted to call \"bless\" on a value that already refers to a real object\ninstance.\n\n• can't convert empty path\n\n(F) On Cygwin, you called a path conversion function with an empty path. Only non-empty\npaths are legal.\n\n• Class already has a superclass, cannot add another\n\n(F) You attempted to specify a second superclass for a \"class\" by using the \":isa\"\nattribute, when one is already specified. Unlike classes whose instances are created\nwith \"bless\", classes created via the \"class\" keyword cannot have more than one\nsuperclass.\n\n• Class attribute %s requires a value\n\n(F) You specified an attribute for a class that would require a value to be passed in\nparentheses, but did not provide one. Remember that whitespace is not permitted between\nthe attribute name and its value; you must write this as\n\nclass Example::Class :attr(VALUE) ...\n\n• Class :isa attribute requires a class but \"%s\" is not one\n\n(F) When creating a subclass using the \"class\" \":isa\" attribute, the named superclass\nmust also be a real class created using the \"class\" keyword.\n\n• Field already has a parameter name, cannot add another\n\n(F) A field may have at most one application of the \":param\" attribute to assign a\nparameter name to it; once applied a second one is not allowed.\n\n• Field attribute %s requires a value\n\n(F) You specified an attribute for a field that would require a value to be passed in\nparentheses, but did not provide one. Remember that whitespace is not permitted between\nthe attribute name and its value; you must write this as\n\nfield $var :attr(VALUE) ...\n\n• Field %s is not accessible outside a method\n\n(F) An attempt was made to access a field variable of a class from code that does not\nappear inside the body of a \"method\" subroutine. This is not permitted, as only methods\nwill have access to the fields of an instance.\n\n• Field %s of \"%s\" is not accessible in a method of \"%s\"\n\n(F) An attempt was made to access a field variable of a class, from a method of another\nclass nested inside the one that actually defined it. This is not permitted, as only\nmethods defined by a given class are permitted to access fields of that class.\n\n• Only scalar fields can take a :param attribute\n\n(F) You tried to apply the \":param\" attribute to an array or hash field. Currently this\nis not permitted.\n\n• Required parameter '%s' is missing for %s constructor\n\n(F) You called the constructor for a class that has a required named parameter, but did\nnot pass that parameter at all.\n\n• Unexpected characters while parsing class :isa attribute: %s\n\n(F) You tried to specify something other than a single class name with an optional\ntrailing version number as the value for a \"class\" \":isa\" attribute. This confused the\nparser.\n\n• Unrecognized class attribute %s\n\n(F) You attempted to add a named attribute to a \"class\" definition, but perl does not\nrecognise the name of the requested attribute.\n\n• Unrecognized field attribute %s\n\n(F) You attempted to add a named attribute to a \"field\" definition, but perl does not\nrecognise the name of the requested attribute.\n\n• ${^HOOK}{%s} may only be a CODE reference or undef\n\n• Attempt to set unknown hook '%s' in %{^HOOK}\n\n• Missing or undefined argument to %s via %{^HOOK}{requirebefore}\n\n• Too many capture groups (limit is %d) in regex m/%s/\n\nNew Warnings\n\n• Unknown locale category %d\n\nThis is a shortened form of an already existing diagnostic, for use when there is no new\nlocale being switched to. The previous diagnostic was misleading in such circumstances.\n\n• Locale '%s' is unsupported, and may crash the interpreter.\n\n• Treating %s::INIT block as BEGIN block as workaround\n\n• Filehandle STD%s reopened as %s only for input\n\n• %s on BEGIN block ignored\n\n• ADJUST is experimental\n\n(S experimental::class) This warning is emitted if you use the \"ADJUST\" keyword of \"use\nfeature 'class'\". This keyword is currently experimental and its behaviour may change in\nfuture releases of Perl.\n\n• class is experimental\n\n(S experimental::class) This warning is emitted if you use the \"class\" keyword of \"use\nfeature 'class'\". This keyword is currently experimental and its behaviour may change in\nfuture releases of Perl.\n\n• Method %s redefined\n\n(W redefine) You redefined a method. To suppress this warning, say\n\n{\nno warnings 'redefine';\n*name = method { ... };\n}\n\n• Odd number of elements in hash field initialization\n\n(W misc) You specified an odd number of elements to initialise a hash field of an object.\nHashes are initialised from a list of key/value pairs so there must be a corresponding\nvalue to every key. The final missing value will be filled in with undef instead.\n\n• Old package separator \"'\" deprecated\n\n(W deprecated, syntax) You used the old package separator \"'\" in a variable, subroutine\nor package name. Support for the old package separator will be removed in Perl 5.40.\n\n• field is experimental\n\n(S experimental::class) This warning is emitted if you use the \"field\" keyword of \"use\nfeature 'class'\". This keyword is currently experimental and its behaviour may change in\nfuture releases of Perl.\n\n• method is experimental\n\n(S experimental::class) This warning is emitted if you use the \"method\" keyword of \"use\nfeature 'class'\". This keyword is currently experimental and its behaviour may change in\nfuture releases of Perl.\n\n• Can't call destructor for 0x%p in global destruction\n" }, { "name": "Changes to Existing Diagnostics", "content": "• The compiler will now stop parsing on the first syntax error it encounters. Historically\nthe compiler would attempt to \"skip past\" the error and continue parsing so that it could\nlist multiple errors. For things like undeclared variables under strict this makes sense.\nFor syntax errors however it has been found that continuing tends to result in a storm of\nunrelated or bizarre errors that mostly just obscure the true error. In extreme cases it\ncan even lead to segfaults and other incorrect behavior.\n\nTherefore we have reformed the continuation logic so that the parse will stop after the\nfirst seen syntax error. Semantic errors like undeclared variables will not stop the\nparse, so you may still see multiple errors when compiling code. However if there is a\nsyntax error it will be the last error message reported by perl and all of the errors\nthat you see will be something that actually needs to be fixed.\n\n• Error messages that output class or package names have been modified to output double\nquoted strings with various characters escaped so as to make the exact value clear to a\nreader. The exact rules on which characters are escaped may change over time but\ncurrently are that printable ASCII codepoints, with the exception of \"\"\" and \"\\\", and\nunicode word characters whose codepoint is over 255 are output raw, and any other symbols\nare escaped much as Data::Dumper might escape them, using \"\\n\" for newline and \"\\\"\" for\ndouble quotes, etc. Codepoints in the range 128-255 are always escaped as they can cause\ntrouble on unicode terminals when output raw.\n\nIn older versions of perl the one liner\n\n$ perl -le'\"thing\\n\"->foo()'\n\nwould output the following error message exactly as shown here, with text spread over\nmultiple lines because the \"\\n\" would be emitted as a raw newline character:\n\nCan't locate object method \"foo\" via package \"thing\n\" (perhaps you forgot to load \"thing\n\"?) at -e line 1.\n\nAs of this release we would output this instead (as one line):\n\nCan't locate object method \"foo\" via package \"thing\\n\"\n(perhaps you forgot to load \"thing\\n\"?) at -e line 1.\n\nNotice the newline in the package name has been quoted and escaped, and thus the error\nmessage is a single line. The text is shown here wrapped to two lines only for\nreadability.\n\n• When package or class names in errors are very large the middle excess portion will be\nelided from the message. As of this release error messages will show only up to the first\n128 characters and the last 128 characters in a package or class name in error messages.\nFor example\n\n$ perl -le'(\"Foo\" x 1000)->new()'\n\nwill output the following as one line:\n\nCan't locate object method \"new\" via package \"FooFooFooFooFooFooFoo\nFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo\nFooFooFooFooFooFooFooFooFooFooFooFooFooFo\"...\"oFooFooFooFooFooFooFoo\nFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo\nFooFooFooFooFooFooFooFooFooFooFooFooFoo\" (perhaps you forgot to load\n\"FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo\nFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFo\"...\n\"oFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo\nFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo\"?)\nat -e line 1.\n\nNotice the \"prefix\"...\"suffix\" form of the package name in this case. In previous\nversions of perl the complete string would have been shown making the error message over\n6k long and there was no upper limit on the length of the error message at all. If you\naccidentally used a 1MB string as a class name then the error message would be over 2MB\nlong. In this perl the upper limit should be around 2k when eliding and escaping are\ntaken into account.\n\n• Removed \"Complex regular subexpression recursion limit (%d) exceeded\"\n\nThe regular expresion engine has not used recursion in some time. This warning no longer\nmakes sense.\n\nSee [GH #19636 ].\n\n• Various warnings that used to produce parenthesized hints underneath the main warning\nmessage and after its \"location data\" were chanaged to put the hint inline with the main\nmessage. For instance:\n\nBareword found where operator expected at -e line 1, near \"foo bar\"\n(Do you need to predeclare foo?)\n\nwill now look like this but as one line:\n\nBareword found where operator expected (Do you need to predeclare\nfoo?) at -e line 1, near \"foo bar\"\n\nas a result such warnings will no longer trigger $SIG{WARN} twice, and the hint will\nbe visible when fatal warnings is in effect.\n\n• The error message that is produced when a \"require\" or \"use\" statement fails has been\nchanged. It used to contain the words \"@INC contains:\", and it used to show the state of\n@INC *after* the require had completed and failed. The error message has been changed to\nsay \"@INC entries checked:\" and to reflect the actual directories or hooks that were\nexecuted during the require statement. For example:\n\nperl -e'push @INC, sub {@INC=()}; eval \"require Frobnitz\"\nor die $@'\nCan't locate Frobnitz.pm in @INC (you may need to install the\nFrobnitz module) (@INC contains:) at (eval 1) line 1.\n\nWill change to (with some output elided for clarity):\n\nperl -e'push @INC, sub {@INC=()}; eval \"require Frobnitz\"\nor die $@'\nCan't locate Frobnitz.pm in @INC (you may need to install the\nFrobnitz module) (@INC entries checked:\n.../siteperl/5.38.0/x8664-linux .../siteperl/5.38.0\n.../5.38.0/x8664-linux .../5.38.0 CODE(0x562745e684b8))\nat (eval 1) line 1.\n\nthus showing the actual directories checked. Code that checks for \"@INC contains:\" in\nerror messages should be hardened against any future wording changes between the @INC and\n\":\", for instance use \"qr/\\@INC[ \\w]+:/\" instead of using \"qr/\\@INC contains:/\" or\n\"qr/\\@INC entries checked:/\" in tests as this will ensure both forward and backward\ncompatibility.\n\n• Old package separator used in string\n\nThis diagnostic is now also part of the \"deprecated\" category.\n\n• given is deprecated replaces \"given is experimental\".\n\n• when is deprecated replaces \"when is experimental\".\n\n• Smartmatch is deprecated replaces \"Smartmatch is experimental\".\n" } ] }, "Configuration and Compilation": { "content": "• \"make -j6 minitest\" could fail due to a build conflict in building \"$(MINIPERLEXE)\"\nbetween the main make process and a child process. [GH #19829\n]\n\n• Properly populate osvers on Dragonfly BSD when the hostname isn't set.\n\n• Fix typos for C99 macro name \"PRIX64\".\n\n• Remove ancient and broken GCC for VMS support\n\n• Remove vestigial reference to \"/VAXC\" qualifier\n\n• Remove sharedperl option on VMS\n\n• VMS now has mkostemp\n\n• \"Configure\" now properly handles quoted elements outputted by gcc. [GH #20606\n]\n\n• \"Configure\" probed for the return type of malloc() and free() by testing whether\ndeclarations for those functions produced a function type mismatch with the\nimplementation. On Solaris, with a C++ compiler, this check always failed, since Solaris\ninstead imports malloc() and free() from \"std::\" with \"using\" for C++ builds. Since the\nreturn types of malloc() and free() are well defined by the C standard, skip probing for\nthem. \"Configure\" command-line arguments and hints can still override these type in the\nunlikely case that is needed. [GH #20806 ]\n", "subsections": [] }, "Testing": { "content": "Tests were added and changed to reflect the other additions and changes in this release.\nFurthermore, these significant changes were made:\n\n• Unicode normalization tests have been added.\n\n• t/test.pl: Add ability to cancel an watchdog timer\n", "subsections": [] }, "Platform Support": { "content": "", "subsections": [ { "name": "Discontinued Platforms", "content": "Ultrix\nSupport code for DEC Ultrix has been removed. Ultrix was the native Unix-like operating\nsystem for various Digital Equipment Corporation machines. Its final release was in\n1995.\n" }, { "name": "Platform-Specific Notes", "content": "DragonflyBSD\nSkip tests to workaround an apparent bug in setproctitle(). [GH #19894\n]\n\nFreeBSD\nFreeBSD no longer uses thread-safe locale operations, to avoid a bug in FreeBSD\n\n\nReplace the first part of archname with \"uname -p\" [GH #19791\n]\n\nSolaris\nAvoid some compiler and compilation issues on NetBSD/Solaris from regexec.c and\nregcomp.c.\n\nSynology\nUpdate Synology Readme for DSM 7.\n\nWindows\nFix win32 memory alignment needed for gcc-12 from vmem.h.\n\nutimes() on Win32 would print a message to stderr if it failed to convert a supplied\n\"timet\" to to a \"FILETIME\". [GH #19668 ]\n\nIn some cases, timestamps returned by stat() and lstat() failed to take daylight saving\ntime into account. [GH #20018 ] [GH #20061\n]\n\nstat() now works on \"AFUNIX\" socket files. [GH #20204\n]\n\nreadlink() now returns the \"PrintName\" from a symbolic link reparse point instead of the\n\"SubstituteName\", which should make it better match the name the link was created with.\n[GH #20271 ]\n\nlstat() on Windows now returns the length of the link target as the size of the file, as\nit does on POSIX systems. [GH #20476 ]\n\nsymlink() on Windows now replaces any \"/\" in the target with \"\\\", since Windows does not\nrecognise \"/\" in symbolic links. The reverse translation is not done by readlink(). [GH\n#20506 ]\n\nsymlink() where the target was an absolute path to a directory was incorrectly created as\na file symbolic link. [GH #20533 ]\n\n\"POSIX::dup2\" no longer creates broken sockets. [GH #20920\n]\n\nClosing a busy pipe could cause Perl to hang. [GH #19963\n]\n" } ] }, "Internal Changes": { "content": "• Removed many deprecated C functions.\n\nThese have been deprecated for a long time. See\n for a\nfull list.\n\n• \"getopdescs\", \"getopnames\", \"getopargs\", \"getnomodify\" and \"getppaddr\" have been\nmarked deprecated.\n\n• \"hvfreeent\" has been marked as internal API.\n\n• \"savepushptr\", \"savepushptrptr\", and \"savepushi32ptr\" have been marked as internal\nAPI.\n\n• New bool related functions and macros have been added to complement the new bool type\nintroduced in 5.36:\n\nThe functions are:\n\n\"newSVbool(const bool boolval)\"\nnewSVtrue()\nnewSVfalse()\n\"svsettrue(SV *sv)\"\n\"svsetfalse(SV *sv)\"\n\"svsetbool(SV *sv, const bool boolval)\"\n\nThe macros are:\n\nSvIandPOK(sv)\nSvIandPOKoff(sv)\n\"SvIandPOKon\"\n• Perl is no longer manipulating the \"environ\" array directly. The variable\n\"PLusesafeputenv\" has been removed and \"PERLUSESAFEPUTENV\" is always defined. This\nmeans XS modules can now call \"setenv\" and \"putenv\" without causing segfaults. [perl\n#19399 ]\n\n• Internal C API functions are now hidden with \"attribute((hidden))\" on the platforms\nthat support it. This means they are no longer callable from XS modules on those\nplatforms.\n\nIt should be noted that those functions have always been hidden on Windows. This change\nmerely brings that to the other platforms. [perl #19655\n]\n\n• New formatting symbols were added for printing values declared as \"U32\" or \"I32\":\n\nI32df -- Like %d\nU32of -- Like %o\nU32uf -- Like %u\nU32xf -- Like %x\nU32Xf -- Like %X\n\nThese are used in the same way already existing similar symbols, such as \"IVdf\", are\nused. See \"I/O Formats\" in perlapi.\n\n• new 'HvHasAUX' macro\n\n• regexec.c: Add some branch predictions reorder conds\n\n• locale: Change macro name to be C conformant\n\n• Rename the \"PADNAMEt*\" constants to \"PADNAMEf*\"\n\n• Changes all the API macros that retrieve a PV into a call to an inline function so as to\nevaluate the parameter just once.\n\n• regexec.c: multiple code refactor to make the code more readable\n\n• perl.h: Change macro name to be C conformant (remove leading from NOTINNUMERIC\nmacros)\n\n• regcomp.h: add new \"BITMAPBIT\" macro in addition to the existing \"BITMAPBYTE\" and\n\"BITMAPTEST\" ones.\n\n• Create new regnode type ANYOFH. populateANYOFfrominvlist was renamed to\npopulatebitmapfrominvlist\n\n• regex: Refactor bitmap vs non-bitmap of qr/[]/\n\n• regcomp.c: add new functions to convert from an inversion list to a bitmap (and vice\nversa) \"populatebitmapfrominvlist\" and \"populateinvlistfrombitmap\".\n\n• Add newAVav() to create an AV from an existing AV. Add newAVhv() to create an AV using\nkeys and values from an existing HV.\n\n• Fix definition of \"Perlatof\".\n\n• Fix undefined behavior with overflow related \"OPTIMIZEINFTY\" and delta in regcomp.c.\n\n• Fix regnode pointer alignment issue in regcomp.h.\n\n• The \"CVfMETHOD\" CV flag and associated \"CvMETHOD\" macro has been renamed to\n\"CVfNOWARNAMBIGUOUS\" and \"CvNOWARNAMBIGUOUS\". This closer reflects its actual\nbehaviour (it suppresses a warning that would otherwise be generated about ambiguous\nnames), in order to be less confusing with \"CvIsMETHOD\", which indicates that a CV is a\n\"method\" subroutine relating to the \"class\" feature.\n\n• The \"OPfSPECIAL\" flag is no longer set on the \"OPENTERSUB\" op constructed to call the\n\"VERSION\", \"import\" and \"unimport\" methods as part of a \"use\" statement and attribute\napplication, nor when assigning to an \":lvalue\" subroutine.\n\n• A new CV flag \"CVfREFCOUNTEDANYSV\" has been added, which indicates that the CV is an\nXSUB and stores an SV pointer in the \"CvXSUBANY.anysv\" union field. Perl core\noperations such as cloning or destroying the CV will maintain the reference count of the\npointed-to SV, destroying it when required.\n\n• A new API function \"\"Perllocaleconv\"\" in perlapi is added. This is the same as\n\"POSIX::localeconv\" (returning a hash of the localeconv() fields), but directly callable\nfrom XS code.\n\n• A new API function, \"\"Perllanginfo8\"\" in perlapi is added. This is the same as plain\n\"\"Perllanginfo\"\" in perlapi, but with an extra parameter that allows the caller to\nsimply and reliably know if the returned string is UTF-8.\n\n• We have introduced a limit on the number of nested \"eval EXPR\"/\"BEGIN\" blocks and\n\"require\"/\"BEGIN\" (and thus \"use\" statements as well) to prevent C stack overflows. This\nvariable can also be used to forbid \"BEGIN\" blocks from executing during \"eval EXPR\"\ncompilation. The limit defaults to 1000 but can be overridden by setting the\n\"${^MAXNESTEDEVALBEGINBLOCKS}\" variable. The default itself can be changed at compile\ntime with\n\n-Accflags='-DPERLMAXNESTEDEVALBEGINBLOCKSDEFAULT=12345'\n\nNote that this value relates to the size of your C stack and if you choose an\ninappropriately large value Perl may segfault, be conservative about what you choose.\n\n• A new magic type \"PERLMAGICextvalue\" has been added. This is available for use like\n\"PERLMAGICext\", but is a value magic: upon localization the new value will not be\nmagical.\n\n• The SSNEW(), SSNEWt(), SSNEWa() and SSNEWat() APIs now return a \"SSizet\" value. The\nSSPTR() and SSPTRt() macros now expect a \"SSizet\" parameter, and enforce that on\ndebugging builds. [GH #20411 ]\n\n• Filenames in cops are now refcounted under threads. Under threads we were copying the\nfilenames into each opcode. This is because in theory opcodes created in one thread can\nbe destroyed in another. The change adds a new struct/type \"RCPV\", which is a refcounted\nstring using shared memory. This is implemented in such a way that code that previously\nused a char * can continue to do so, as the refcounting data is located a specific offset\nbefore the char * pointer itself.\n\n• Added \"HvNAMEf\" and \"HvNAMEfQUOTEDPREFIX\" special formats. They take an \"HV *\" as an\nargument and use HvNAME() and related macros to determine the string, its length, and\nwhether it is utf8.\n\n• The underlying \"Perldowantarray\" function implementing the long-deprecated \"GIMME\" macro\nhas been marked as deprecated, so that use of the macro emits a compile-time warning.\n\"GIMME\" has been documented as deprecated in favour of \"GIMMEV\" since Perl v5.6.0, but\nhad not previously issued a warning.\n\n• The API function \"utf8length\" in perlapi is now more efficient.\n\n• Added SAVERCPV() and SAVEFREERCPV() for better support for working with \"RCPV\" (reference\ncounted string/pointer value) structures which currently are used in opcodes to share\nfilename and warning bit data in a memory efficient manner.\n\n• Added MORTALSVFUNCSV() and MORTALDESTRUCTORSV() macros, which make it possible to\ncreate a destructor which is fired at the end of the current statement. This uses the\n\"PERLMAGICdestruct\" magic to use \"free\" magic to trigger an action when a variable is\nfreed. The action can be specified as a C function or as a Perl code reference.\n\n• Added the \"%{^HOOK}\" api and related \"PERLMAGIChook\" and \"PERLMAGIChookelem\" for\nproviding ways to hook selected perl functions which for one reason or another are\nproblematic to wrap with a customized subroutine.\n\n• Added support for \"${^HOOK}{requirebefore}\" which can be used to rewrite the filename\nthat \"require\" will try to load, and also to block \"require\" from loading a specific\nmodule, even via fully qualified filename. The hook can also be used to perform \"pre-\nrequire\" and \"post-require\" actions.\n\n• Added support for \"${^HOOK}{requireafter}\" which can be used to track what modules have\nbeen required after the fact.\n\n• Regular expression opcodes (regops) now use a standardized structure layout that uses\nunions to expose data in different format. This means it should be much easier to extend\nor modify regops to use more memory. This has been used to make a number of regops track\nhow many parens they contain.\n", "subsections": [] }, "Selected Bug Fixes": { "content": "• Avoid recursion and stack overflow parsing 'pack' template\n\n[GH #16319 ]\n\n• An eval() as the last statement in a regex code block could trigger an interpreter panic;\ne.g.\n\n/(?{ ...; eval {....}; })/\n\n[GH #19680 ]\n\n• Disabling the \"barewordfilehandles\" feature no longer treats \"print Class->method\" as an\nerror. [GH #19704 ]\n\n• When a Perl subroutine tail-calls an XS subroutine using \"goto &xssub\", the XS\nsubroutine can now correctly determine its calling context. Previously it was always\nreported as scalar.\n\nIn addition, where the Perl subroutine is freed at the same time:\n\nsub foo { *foo = sub {}; goto &xssub }\n\nthis formerly could lead to crashes if the XS subroutine tried to use the value of\n\"PLop\", since this was being set to NULL. This is now fixed.\n\n[GH #19936 ]\n\n• setsockopt() now uses the mechanism added in 5.36 to better distinguish between numeric\nand string values supplied as the \"OPTVAL\" parameter. [GH #18761\n]\n\n• 4-argument select() now rejects strings with code points above 255. Additionally, for\ncode points 128-255, this operator will now always give the corresponding octet to the\nOS, regardless of how Perl stores such code points in memory. (Previously Perl leaked its\ninternal string storage to the OS.) [GH #19882\n]\n\n• Fix panic issue from \"val {} inside /(?{...})/\" [GH #19390\n]\n\n• Fix multiple compiler warnings from regexp.c, locale.c [GH #19915\n]\n\n• Fix a bug with querying locales on platforms that don't have \"LCNUMERIC\" [GH #19890\n]\n\n• Prevent undefined behaviour in Smaybemultideref().\n\n• Avoid signed integer overflow in \"use integer\" ops.\n\n• Avoid adding an offset to a NULL pointer in \"hvdeletecommon\".\n\n• PerlIO::getlayers will now accept IO references too\n\nPreviously it would only take glob references or names of globs. Now it will also accept\nIO references.\n\n• Fixes to memory handling for \"PLsplitstr\":\n\n• If a thread was created the allocated string would be freed twice.\n\n• If two \"-F\" switches were supplied the memory allocated for the first switch wouldn't\nbe freed.\n\n• Correctly handle \"OPANONCODE\" ops generated by CPAN modules that don't include the\nOPfREF flag when propagating lvalue context. [GH #20532\n]\n\n• POSIX::strxfrm now uses the \"LCCTYPE\" locale category to specify its collation, ignoring\nany differing \"LCCOLLATE\". It doesn't make sense for a string to be encoded in one\nlocale (say, ISO-8859-6, Arabic) and to collate it based on another (like ISO-8859-7,\nGreek). Perl assumes that the current \"LCCTYPE\" locale correctly represents the\nencoding, and collates accordingly.\n\nAlso, embedded \"NUL\" characters are now allowed in the input.\n\nIf locale collation is not enabled on the platform (\"LCCOLLATE\"), the input is returned\nunchanged.\n\n• Double FETCH during stringification of tied scalars returning an overloaded object have\nbeen fixed. The FETCH method should only be called once, but prior to this release was\nactually called twice. [GH #20574 ]\n\n• Writing to a magic variables associated with the selected output handle, $^, $~, $=, \"$-\"\nand $%, no longer crashes perl if the IO object has been cleared from the selected output\nhandle. [GH #20733 ]\n\n• Redefining a \"use constant\" list constant with \"use constant\" now properly warns. This\nchanges the behaviour of \"use constant\" but is a core change, not a change to\nconstant.pm. [GH #20742 ]\n\n• Redefining a \"use constant\" list constant with an empty prototype constant sub would\nresult in an assertion failure. [GH #20742 ]\n\n• Fixed a regression where the \"INC\" method for objects in @INC would not be resolved by\n\"AUTOLOAD\", while it was in 5.36. The \"INCDIR\" method for objects in @INC cannot be\nresolved by \"AUTOLOAD\" as \"INC\" would have been resolved first. [GH #20665\n]\n\n• $SIG{DIE} will now be called from eval when the code dies during compilation\nregardless of how it dies. This means that code expecting to be able to upgrade $@ into\nan object will be called consistently. In earlier versions of perl $SIG{DIE} would\nnot be called for certain compilation errors, for instance undeclared variables. For\nother errors it might be called if there were more than a certain number of errors, but\nnot if there were less. Now you can expect that it will be called in every case.\n\n• Compilation of code with errors used to inconsistently stop depending on the count and\ntype of errors encountered. The intent was that after 10 errors compilation would halt,\nbut bugs in this logic meant that certain types of error would be counted, but would not\ntrigger the threshold check to stop compilation. Other errors would. With this release\nafter at most 10 errors compilation will terminate, regardless of what type of error they\nwere.\n\nNote that you can change the maximum count by defining \"PERLSTOPPARSINGAFTERNERRORS\"\nto be something else during the configuration process. For instance\n\n./Configure ... -Accflags='-DPERLSTOPPARSINGAFTERNERRORS=100'\n\nwould allow up to 100 errors.\n\n• The API function \"mysnprintf\" in perlapi now prints a non-dot decimal point if the perl\ncode it ultimately is called from is in the scope of \"use locale\" and the locale in\neffect calls for that.\n\n• A number of bugs related to capture groups in quantified groups in regular expression\nhave been fixed, especially in alternations. For example in a pattern like:\n\n\"foobazfoobar\" =~ /((foo)baz|foo(bar))+/\n\nthe regex variable $2 will not be \"foo\" as it once was, it will be undef.\n\n• Bugs with regex backreference operators that are inside of a capture group have been\nfixed. For instance:\n\n\"xa=xaaa\" =~ /^(xa|=?\\1a){2}\\z/\n\nwill now correctly not match. [GH #10073 ]\n\n• SSGROW() and SSCHECK() have been reworked to ensure that the requested space is actually\nallocated. SSCHECK() is now an alias for SSGROW().\n", "subsections": [] }, "Acknowledgements": { "content": "Perl 5.38.0 represents approximately 12 months of development since Perl 5.36.0 and contains\napproximately 290,000 lines of changes across 1,500 files from 100 authors.\n\nExcluding auto-generated files, documentation and release tools, there were approximately\n190,000 lines of changes to 970 .pm, .t, .c and .h files.\n\nPerl continues to flourish into its fourth decade thanks to a vibrant community of users and\ndevelopers. The following people are known to have contributed the improvements that became\nPerl 5.38.0:\n\nAlex, Alexander Nikolov, Alex Davies, Andreas König, Andrew Fresh, Andrew Ruthven, Andy\nLester, Aristotle Pagaltzis, Arne Johannessen, A. Sinan Unur, Bartosz Jarzyna, Bart Van\nAssche, Benjamin Smith, Bram, Branislav Zahradník, Brian Greenfield, Bruce Gray, Chad Granum,\nChris 'BinGOs' Williams, chromatic, Clemens Wasser, Craig A. Berry, Dagfinn Ilmari Mannsåker,\nDan Book, danielnachun, Dan Jacobson, Dan Kogai, David Cantrell, David Golden, David\nMitchell, E. Choroba, Ed J, Ed Sabol, Elvin Aslanov, Eric Herman, Felipe Gasper, Ferenc Erki,\nFiras Khalil Khana, Florian Weimer, Graham Knop, Håkon Hægland, Harald Jörg, H.Merijn Brand,\nHugo van der Sanden, James E Keenan, James Raspass, jkahrman, Joe McMahon, Johan Vromans,\nJonathan Stowe, Jon Gentle, Karen Etheridge, Karl Williamson, Kenichi Ishigaki, Kenneth\nÖlwing, Kurt Fitzner, Leon Timmermans, Li Linjie, Loren Merritt, Lukas Mai, Marcel Telka,\nMark Jason Dominus, Mark Shelor, Matthew Horsfall, Matthew O. Persico, Mattia Barbon, Max\nMaischein, Mohammad S Anwar, Nathan Mills, Neil Bowers, Nicholas Clark, Nicolas Mendoza,\nNicolas R, Paul Evans, Paul Marquess, Peter John Acklam, Peter Levine, Philippe Bruhat\n(BooK), Reini Urban, Renee Baecker, Ricardo Signes, Richard Leach, Russ Allbery, Scott Baker,\nSevan Janiyan, Sidney Markowitz, Sisyphus, Steve Hay, TAKAI Kousuke, Todd Rinaldo, Tomasz\nKonojacki, Tom Stellard, Tony Cook, Tsuyoshi Watanabe, Unicode Consortium, vsfos, Yves Orton,\nZakariyya Mughal, Zefram, 小鸡.\n\nThe list above is almost certainly incomplete as it is automatically generated from version\ncontrol history. In particular, it does not include the names of the (very much appreciated)\ncontributors who reported issues to the Perl bug tracker.\n\nMany of the changes included in this version originated in the CPAN modules included in\nPerl's core. We're grateful to the entire CPAN community for helping Perl to flourish.\n\nFor a more complete list of all of Perl's historical contributors, please see the AUTHORS\nfile in the Perl source distribution.\n", "subsections": [] }, "Reporting Bugs": { "content": "If you find what you think is a bug, you might check the perl bug database at\n. There may also be information at\n, the Perl Home Page.\n\nIf you believe you have an unreported bug, please open an issue at\n. Be sure to trim your bug down to a tiny but\nsufficient test case.\n\nIf the bug you are reporting has security implications which make it inappropriate to send to\na public issue tracker, then see \"SECURITY VULNERABILITY CONTACT INFORMATION\" in perlsec for\ndetails of how to report the issue.\n", "subsections": [] }, "Give Thanks": { "content": "If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, you can do so by\nrunning the \"perlthanks\" program:\n\nperlthanks\n\nThis will send an email to the Perl 5 Porters list with your show of thanks.\n", "subsections": [] }, "SEE ALSO": { "content": "The Changes file for an explanation of how to view exhaustive details on what changed.\n\nThe INSTALL file for how to build Perl.\n\nThe README file for general stuff.\n\nThe Artistic and Copying files for copyright information.\n\nperl v5.38.2 2026-06-12 PERL5380DELTA(1)", "subsections": [] } } } }