=head1 DESCRIPTION
-This document explains how Perl development works. It includes details
+This document explains how Perl development works. It includes details
about the Perl 5 Porters email list, the Perl repository, the Perlbug
bug tracker, patch guidelines, and commentary on Perl development
philosophy.
=item * Check out the source repository
-The perl source is in a git repository. You can clone the repository
+The perl source is in a git repository. You can clone the repository
with the following command:
% git clone git://perl5.git.perl.org/perl.git perl
+=item * Ensure you're following the latest advice
+
+In case the advice in this guide has been updated recently, read the
+latest version directly from the perl source:
+
+ % perldoc pod/perlhack.pod
+
=item * Make your change
-Hack, hack, hack.
+Hack, hack, hack. Keep in mind that Perl runs on many different
+platforms, with different operating systems that have different
+capabilities, different filesystem organizations, and even different
+character sets. L<perlhacktips> gives advice on this.
=item * Test your change
% git commit -a -m 'Commit message goes here'
Make sure the commit message describes your change in a single
-sentence. For example, "Fixed spelling errors in perlhack.pod".
+sentence. For example, "Fixed spelling errors in perlhack.pod".
=item * Send your change to perlbug
The next step is to submit your patch to the Perl core ticket system
via email.
-Assuming your patch consists of a single git commit, you can send it to
-perlbug with this command line:
+If your changes are in a single git commit, run the following commands
+to generate the patch file and attach it to your bug report:
% git format-patch -1
- % perlbug -s "[PATCH] $(git log -1 --oneline HEAD)" -f 0001-*.patch
+ % ./perl -Ilib utils/perlbug -p 0001-*.patch
The perlbug program will ask you a few questions about your email
-address and the patch you're submitting. Once you've answered them you
-can submit your patch.
+address and the patch you're submitting. Once you've answered them it
+will submit your patch via email.
+
+If your changes are in multiple commits, generate a patch file for each
+one and provide them to perlbug's C<-p> option separated by commas:
+
+ % git format-patch -3
+ % ./perl -Ilib utils/perlbug -p 0001-fix1.patch,0002-fix2.patch,\
+ > 0003-fix3.patch
+
+When prompted, pick a subject that summarizes your changes.
=item * Thank you
The porters appreciate the time you spent helping to make Perl better.
Thank you!
+=item * Acknowledgement
+
+All contributors are credited (by name and email address) in the
+AUTHORS file, which is part of the perl distribution, as well as the
+Git commit history.
+
+If you don’t want to be included in the AUTHORS file, just let us
+know. Otherwise we will take your submission of a patch as permission
+to credit you in the AUTHORS file.
+
+=item * Next time
+
+The next time you wish to make a patch, you need to start from the
+latest perl in a pristine state. Check you don't have any local changes
+or added files in your perl check-out which you wish to keep, then run
+these commands:
+
+ % git pull
+ % git reset --hard origin/blead
+ % git clean -dxf
+
=back
=head1 BUG REPORTING
-If you want to report a bug in Perl, you must use the F<perlbug> command
-line tool. This tool will ensure that your bug report includes all the
-relevant system and configuration information.
+If you want to report a bug in Perl, you must use the F<perlbug>
+command line tool. This tool will ensure that your bug report includes
+all the relevant system and configuration information.
To browse existing Perl bugs and patches, you can use the web interface
at L<http://rt.perl.org/>.
Please check the archive of the perl5-porters list (see below) and/or
-the bug tracking system before submitting a bug report. Often, you'll
+the bug tracking system before submitting a bug report. Often, you'll
find that the bug has been reported already.
You can log in to the bug tracking system and comment on existing bug
-reports. If you have additional information regarding an existing bug,
-please add it. This will help the porters fix the bug.
+reports. If you have additional information regarding an existing bug,
+please add it. This will help the porters fix the bug.
=head1 PERL 5 PORTERS
The perl5-porters (p5p) mailing list is where the Perl standard
-distribution is maintained and developed. The people who maintain Perl
-are also referred to as the "Perl 5 Porters", or just the "porters".
+distribution is maintained and developed. The people who maintain Perl
+are also referred to as the "Perl 5 Porters", "p5p" or just the
+"porters".
A searchable archive of the list is available at
-L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/>. There is
-also another archive at
+L<http://markmail.org/search/?q=perl5-porters>. There is also an archive at
L<http://archive.develooper.com/perl5-porters@perl.org/>.
=head2 perl-changes mailing list
The perl5-changes mailing list receives a copy of each patch that gets
submitted to the maintenance and development branches of the perl
-repository. See L<http://lists.perl.org/list/perl5-changes.html> for
+repository. See L<https://lists.perl.org/list/perl5-changes.html> for
subscription and archive information.
+=head2 #p5p on IRC
+
+Many porters are also active on the L<irc://irc.perl.org/#p5p> channel.
+Feel free to join the channel and ask questions about hacking on the
+Perl core.
+
=head1 GETTING THE PERL SOURCE
All of Perl's source code is kept centrally in a Git repository at
-I<perl5.git.perl.org>. The repository contains many Perl revisions from
-Perl 1 onwards and all the revisions from Perforce, the previous
+I<perl5.git.perl.org>. The repository contains many Perl revisions
+from Perl 1 onwards and all the revisions from Perforce, the previous
version control system.
For much more detail on using git with the Perl repository, please see
=head2 Read access via Git
-You will need a copy of Git for your computer. You can fetch a copy of
+You will need a copy of Git for your computer. You can fetch a copy of
the repository using the git protocol:
% git clone git://perl5.git.perl.org/perl.git perl
=head2 Read access via the web
-You may access the repository over the web. This allows you to browse
+You may access the repository over the web. This allows you to browse
the tree, see recent commits, subscribe to RSS feeds for the changes,
-search for particular commits and more. You may access it at
-L<http://perl5.git.perl.org/perl.git>. A mirror of the repository is
-found at L<http://github.com/mirrors/perl>.
+search for particular commits and more. You may access it at
+L<http://perl5.git.perl.org/perl.git>. A mirror of the repository is
+found at L<https://github.com/Perl/perl5>.
=head2 Read access via rsync
You can also choose to use rsync to get a copy of the current source
tree for the bleadperl branch and all maintenance branches:
- % rsync -avz rsync://perl5.git.perl.org/perl-current .
- % rsync -avz rsync://perl5.git.perl.org/perl-5.12.x .
- % rsync -avz rsync://perl5.git.perl.org/perl-5.10.x .
- % rsync -avz rsync://perl5.git.perl.org/perl-5.8.x .
- % rsync -avz rsync://perl5.git.perl.org/perl-5.6.x .
- % rsync -avz rsync://perl5.git.perl.org/perl-5.005xx .
+ % rsync -avz rsync://perl5.git.perl.org/perl-current .
+ % rsync -avz rsync://perl5.git.perl.org/perl-5.12.x .
+ % rsync -avz rsync://perl5.git.perl.org/perl-5.10.x .
+ % rsync -avz rsync://perl5.git.perl.org/perl-5.8.x .
+ % rsync -avz rsync://perl5.git.perl.org/perl-5.6.x .
+ % rsync -avz rsync://perl5.git.perl.org/perl-5.005xx .
(Add the C<--delete> option to remove leftover files.)
To get a full list of the available sync points:
- % rsync perl5.git.perl.org::
+ % rsync perl5.git.perl.org::
=head2 Write access via git
=head1 PATCHING PERL
If you're planning to do more extensive work than a single small fix,
-we encourage you to read the documentation below. This will help you
+we encourage you to read the documentation below. This will help you
focus your work and make your patches easier to incorporate into the
Perl source.
=head2 Submitting patches
-If you have a small patch to submit, please submit it via perlbug. You
-can also send email directly to perlbug@perl.org. Please note that
+If you have a small patch to submit, please submit it via perlbug. You
+can also send email directly to perlbug@perl.org. Please note that
messages sent to perlbug may be held in a moderation queue, so you
won't receive a response immediately.
You'll know your submission has been processed when you receive an
-email from our ticket tracking system. This email will give you a
-ticket number. Once your patch has made it to the ticket tracking
+email from our ticket tracking system. This email will give you a
+ticket number. Once your patch has made it to the ticket tracking
system, it will also be sent to the perl5-porters@perl.org list.
-Patches are reviewed and discussed on the p5p list. Simple,
+If your patch is related to an already-opened ticket you can also
+attach your patch to that ticket, without having to use perlbug.
+
+Patches are reviewed and discussed on the p5p list. Simple,
uncontroversial patches will usually be applied without any discussion.
When the patch is applied, the ticket will be updated and you will
-receive email. In addition, an email will be sent to the p5p list.
+receive email. In addition, an email will be sent to the p5p list.
-In other cases, the patch will need more work or discussion. That will
+In other cases, the patch will need more work or discussion. That will
happen on the p5p list.
You are encouraged to participate in the discussion and advocate for
-your patch. Sometimes your patch may get lost in the shuffle. It's
+your patch. Sometimes your patch may get lost in the shuffle. It's
appropriate to send a reminder email to p5p if no action has been taken
-in a month. Please remember that the Perl 5 developers are all
+in a month. Please remember that the Perl 5 developers are all
volunteers, and be polite.
Changes are always applied directly to the main development branch,
-called "blead". Some patches may be backported to a maintenance branch.
-If you think your patch is appropriate for the maintenance branch,
-please explain why when you submit it.
+called "blead". Some patches may be backported to a maintenance
+branch. If you think your patch is appropriate for the maintenance
+branch (see L<perlpolicy/MAINTENANCE BRANCHES>), please explain why
+when you submit it.
=head2 Getting your patch accepted
=head3 Patch style
If you used git to check out the Perl source, then using C<git
-format-patch> will produce a patch in a style suitable for Perl. The
+format-patch> will produce a patch in a style suitable for Perl. The
C<format-patch> command produces one patch file for each commit you
-made. If you prefer to send a single patch for all commits, you can use
-C<git diff>.
+made. If you prefer to send a single patch for all commits, you can
+use C<git diff>.
- % git co blead
+ % git checkout blead
% git pull
% git diff blead my-branch-name
This produces a patch based on the difference between blead and your
-current branch. It's important to make sure that blead is up to date
+current branch. It's important to make sure that blead is up to date
before producing the diff, that's why we call C<git pull> first.
-We strongly recommend that you use git if possible. It will make your
+We strongly recommend that you use git if possible. It will make your
life easier, and ours as well.
However, if you're not using git, you can still produce a suitable
-patch. You'll need a pristine copy of the Perl source to diff against.
-The porters prefer unified diffs. Using GNU C<diff>, you can produce a
+patch. You'll need a pristine copy of the Perl source to diff against.
+The porters prefer unified diffs. Using GNU C<diff>, you can produce a
diff like this:
% diff -Npurd perl.pristine perl.mine
=head3 Commit message
As you craft each patch you intend to submit to the Perl core, it's
-important to write a good commit message. This is especially important
+important to write a good commit message. This is especially important
if your submission will consist of a series of commits.
The first line of the commit message should be a short description
-without a period. It should be no longer than the subject line of an
+without a period. It should be no longer than the subject line of an
email, 50 characters being a good rule of thumb.
A lot of Git tools (Gitweb, GitHub, git log --pretty=oneline, ...) will
=item * Why
Your commit message should describe why the change you are making is
-important. When someone looks at your change in six months or six
+important. When someone looks at your change in six months or six
years, your intent should be clear.
If you're deprecating a feature with the intent of later simplifying
-another bit of code, say so. If you're fixing a performance problem or
+another bit of code, say so. If you're fixing a performance problem or
adding a new feature to support some other bit of the core, mention
that.
=back
A commit message isn't intended to take the place of comments in your
-code. Commit messages should describe the change you made, while code
+code. Commit messages should describe the change you made, while code
comments should describe the current state of the code.
If you've just implemented a new feature, complete with doc, tests and
-well-commented code, a brief commit message will often suffice. If,
+well-commented code, a brief commit message will often suffice. If,
however, you've just changed a single character deep in the parser or
lexer, you might need to write a small novel to ensure that future
readers understand what you did and why you did it.
=head3 Comments, Comments, Comments
-Be sure to adequately comment your code. While commenting every line is
-unnecessary, anything that takes advantage of side effects of
+Be sure to adequately comment your code. While commenting every line
+is unnecessary, anything that takes advantage of side effects of
operators, that creates changes that will be felt outside of the
function being patched, or that others may find confusing should be
-documented. If you are going to err, it is better to err on the side of
-adding too many comments than too few.
+documented. If you are going to err, it is better to err on the side
+of adding too many comments than too few.
The best comments explain I<why> the code does what it does, not I<what
it does>.
=item *
-8-wide tabs (no exceptions!)
+4-wide indents for code, 2-wide indents for nested CPP C<#define>s,
+with 8-wide tabstops.
=item *
-4-wide indents for code, 2-wide indents for nested CPP #defines
+Use spaces for indentation, not tab characters.
+
+The codebase is a mixture of tabs and spaces for indentation, and we
+are moving to spaces only. Converting lines you're patching from 8-wide
+tabs to spaces will help this migration.
=item *
=item *
-In function definitions, name starts in column 0 (return value is on
+In function definitions, name starts in column 0 (return value-type is on
previous line)
=item *
"if (!foo) ..." rather than "if (foo == FALSE) ..." etc.
+=item *
+
+Do not declare variables using "register". It may be counterproductive
+with modern compilers, and is deprecated in C++, under which the Perl
+source is regularly compiled.
+
+=item *
+
+In-line functions that are in headers that are accessible to XS code
+need to be able to compile without warnings with commonly used extra
+compilation flags, such as gcc's C<-Wswitch-default> which warns
+whenever a switch statement does not have a "default" case. The use of
+these extra flags is to catch potential problems in legal C code, and
+is often used by Perl aggregators, such as Linux distributors.
+
=back
=head3 Test suite
If your patch changes code (rather than just changing documentation),
you should also include one or more test cases which illustrate the bug
-you're fixing or validate the new functionality you're adding. In
+you're fixing or validate the new functionality you're adding. In
general, you should update an existing test file rather than create a
new one.
=item *
-Know what you're testing. Read the docs, and the source.
+Know what you're testing. Read the docs, and the source.
=item *
=item *
-Avoid using qx// and system() unless you are testing for them. If you
+Avoid using qx// and system() unless you are testing for them. If you
do use them, make sure that you cover _all_ perl platforms.
=item *
=item *
-Make updating the '1..42' string unnecessary. Or make sure that you
+Make updating the '1..42' string unnecessary. Or make sure that you
update it.
=item *
This works just like patching anything else, with one extra
consideration.
-Some core modules also live on CPAN and are maintained outside of the
-Perl core. When the author updates the module, the updates are simply
-copied into the core.
-
Modules in the F<cpan/> directory of the source tree are maintained
-outside of the Perl core. See that module's listing on documentation or
-its listing on L<http://search.cpan.org/> for more information on
-reporting bugs and submitting patches.
+outside of the Perl core. When the author updates the module, the
+updates are simply copied into the core. See that module's
+documentation or its listing on L<http://search.cpan.org/> for more
+information on reporting bugs and submitting patches.
+
+In most cases, patches to modules in F<cpan/> should be sent upstream
+and should not be applied to the Perl core individually. If a patch to
+a file in F<cpan/> absolutely cannot wait for the fix to be made
+upstream, released to CPAN and copied to blead, you must add (or
+update) a C<CUSTOMIZED> entry in the F<"Porting/Maintainers.pl"> file
+to flag that a local modification has been made. See
+F<"Porting/Maintainers.pl"> for more details.
In contrast, modules in the F<dist/> directory are maintained in the
core.
For changes significant enough to warrant a F<pod/perldelta.pod> entry,
the porters will greatly appreciate it if you submit a delta entry
-along with your actual change. Significant changes include, but are not
-limited to:
+along with your actual change. Significant changes include, but are
+not limited to:
=over 4
=back
Please make sure you add the perldelta entry to the right section
-within F<pod/perldelta.pod>. More information on how to write good
+within F<pod/perldelta.pod>. More information on how to write good
perldelta entries is available in the C<Style> section of
F<Porting/how_to_write_a_perldelta.pod>.
=head2 What makes for a good patch?
-New features and extensions to the language can be contentious. There
+New features and extensions to the language can be contentious. There
is no specific set of criteria which determine what features get added,
but here are some questions to consider when developing a patch:
=head3 Where is the implementation?
-All the talk in the world is useless without an implementation. In
+All the talk in the world is useless without an implementation. In
almost every case, the person or people who argue for a new feature
-will be expected to be the ones who implement it. Porters capable of
+will be expected to be the ones who implement it. Porters capable of
coding new features have their own agendas, and are not available to
implement your (possibly good) idea.
=head3 Backwards compatibility
-It's a cardinal sin to break existing Perl programs. New warnings can
+It's a cardinal sin to break existing Perl programs. New warnings can
be contentious--some say that a program that emits warnings is not
-broken, while others say it is. Adding keywords has the potential to
+broken, while others say it is. Adding keywords has the potential to
break programs, changing the meaning of existing token sequences or
functions might break programs.
The Perl 5 core includes mechanisms to help porters make backwards
incompatible changes more compatible such as the L<feature> and
-L<deprecate> modules. Please use them when appropriate.
+L<deprecate> modules. Please use them when appropriate.
=head3 Could it be a module instead?
Perl 5 has extension mechanisms, modules and XS, specifically to avoid
-the need to keep changing the Perl interpreter. You can write modules
+the need to keep changing the Perl interpreter. You can write modules
that export functions, you can give those functions prototypes so they
can be called like built-in functions, you can even write XS code to
mess with the runtime data structures of the Perl interpreter if you
=head3 How big is it?
-The smaller and more localized the change, the better. Similarly, a
+The smaller and more localized the change, the better. Similarly, a
series of small patches is greatly preferred over a single large patch.
=head3 Does it preclude other desirable features?
A patch is likely to be rejected if it closes off future avenues of
-development. For instance, a patch that placed a true and final
+development. For instance, a patch that placed a true and final
interpretation on prototypes is likely to be rejected because there are
still options for the future of prototypes that haven't been addressed.
=head3 Is the implementation robust?
Good patches (tight code, complete, correct) stand more chance of going
-in. Sloppy or incorrect patches might be placed on the back burner
+in. Sloppy or incorrect patches might be placed on the back burner
until the pumpking has time to fix, or might be discarded altogether
without further notice.
=head3 Is the implementation generic enough to be portable?
-The worst patches make use of system-specific features. It's highly
+The worst patches make use of system-specific features. It's highly
unlikely that non-portable additions to the Perl language will be
accepted.
=head3 Is there enough documentation?
Patches without documentation are probably ill-thought out or
-incomplete. No features can be added or changed without documentation,
+incomplete. No features can be added or changed without documentation,
so submitting a patch for the appropriate pod docs as well as the
source code is important.
=head3 Is there another way to do it?
Larry said "Although the Perl Slogan is I<There's More Than One Way to
-Do It>, I hesitate to make 10 ways to do something". This is a tricky
+Do It>, I hesitate to make 10 ways to do something". This is a tricky
heuristic to navigate, though--one man's essential addition is another
man's pointless cruft.
=head3 Patches speak louder than words
-Working code is always preferred to pie-in-the-sky ideas. A patch to
+Working code is always preferred to pie-in-the-sky ideas. A patch to
add a feature stands a much higher chance of making it to the language
than does a random feature request, no matter how fervently argued the
-request might be. This ties into "Will it be useful?", as the fact that
-someone took the time to make the patch demonstrates a strong desire
-for the feature.
+request might be. This ties into "Will it be useful?", as the fact
+that someone took the time to make the patch demonstrates a strong
+desire for the feature.
=head1 TESTING
"ok/not ok" run through Test::Harness, but there are a few special
considerations.
-There are three ways to write a test in the core. L<Test::More>,
-F<t/test.pl> and ad hoc C<print $test ? "ok 42\n" : "not ok 42\n">. The
-decision of which to use depends on what part of the test suite you're
-working on. This is a measure to prevent a high-level failure (such as
-Config.pm breaking) from causing basic functionality tests to fail.
+There are three ways to write a test in the core: L<Test::More>,
+F<t/test.pl> and ad hoc C<print $test ? "ok 42\n" : "not ok 42\n">.
+The decision of which to use depends on what part of the test suite
+you're working on. This is a measure to prevent a high-level failure
+(such as Config.pm breaking) from causing basic functionality tests to
+fail.
The F<t/test.pl> library provides some of the features of
L<Test::More>, but avoids loading most modules and uses as few core
features as possible.
-If you write your own test, use the L<Test Anything Protocol|http://testanything.org>.
+If you write your own test, use the L<Test Anything
+Protocol|http://testanything.org>.
=over 4
-=item * F<t/base> and F<t/comp>
+=item * F<t/base>, F<t/comp> and F<t/opbasic>
-Since we don't know if require works, or even subroutines, use ad hoc
-tests for these two. Step carefully to avoid using the feature being
-tested.
+Since we don't know if C<require> works, or even subroutines, use ad hoc
+tests for these three. Step carefully to avoid using the feature being
+tested. Tests in F<t/opbasic>, for instance, have been placed there
+rather than in F<t/op> because they test functionality which
+F<t/test.pl> presumes has already been demonstrated to work.
=item * F<t/cmd>, F<t/run>, F<t/io> and F<t/op>
=item * Everything else
Now that the core of Perl is tested, L<Test::More> can and should be
-used. You can also use the full suite of core modules in the tests.
+used. You can also use the full suite of core modules in the tests.
=back
When you say "make test", Perl uses the F<t/TEST> program to run the
-test suite (except under Win32 where it uses F<t/harness> instead). All
-tests are run from the F<t/> directory, B<not> the directory which
-contains the test. This causes some problems with the tests in F<lib/>,
-so here's some opportunity for some patching.
+test suite (except under Win32 where it uses F<t/harness> instead).
+All tests are run from the F<t/> directory, B<not> the directory which
+contains the test. This causes some problems with the tests in
+F<lib/>, so here's some opportunity for some patching.
+
+You must be triply conscious of cross-platform concerns. This usually
+boils down to using L<File::Spec>, avoiding things like C<fork()>
+and C<system()> unless absolutely necessary, and not assuming that a
+given character has a particular ordinal value (code point) or that its
+UTF-8 representation is composed of particular bytes.
+
+There are several functions available to specify characters and code
+points portably in tests. The always-preloaded functions
+C<utf8::unicode_to_native()> and its inverse
+C<utf8::native_to_unicode()> take code points and translate
+appropriately. The file F<t/charset_tools.pl> has several functions
+that can be useful. It has versions of the previous two functions
+that take strings as inputs -- not single numeric code points:
+C<uni_to_native()> and C<native_to_uni()>. If you must look at the
+individual bytes comprising a UTF-8 encoded string,
+C<byte_utf8a_to_utf8n()> takes as input a string of those bytes encoded
+for an ASCII platform, and returns the equivalent string in the native
+platform. For example, C<byte_utf8a_to_utf8n("\xC2\xA0")> returns the
+byte sequence on the current platform that form the UTF-8 for C<U+00A0>,
+since C<"\xC2\xA0"> are the UTF-8 bytes on an ASCII platform for that
+code point. This function returns C<"\xC2\xA0"> on an ASCII platform, and
+C<"\x80\x41"> on an EBCDIC 1047 one.
+
+But easiest is, if the character is specifiable as a literal, like
+C<"A"> or C<"%">, to use that; if not so specificable, you can use use
+C<\N{}> , if the side effects aren't troublesome. Simply specify all
+your characters in hex, using C<\N{U+ZZ}> instead of C<\xZZ>. C<\N{}>
+is the Unicode name, and so it
+always gives you the Unicode character. C<\N{U+41}> is the character
+whose Unicode code point is C<0x41>, hence is C<'A'> on all platforms.
+The side effects are:
+
+=over 4
-You must be triply conscious of cross-platform concerns. This usually
-boils down to using L<File::Spec> and avoiding things like C<fork()>
-and C<system()> unless absolutely necessary.
+=item *
+
+These select Unicode rules. That means that in double-quotish strings,
+the string is always converted to UTF-8 to force a Unicode
+interpretation (you can C<utf8::downgrade()> afterwards to convert back
+to non-UTF8, if possible). In regular expression patterns, the
+conversion isn't done, but if the character set modifier would
+otherwise be C</d>, it is changed to C</u>.
+
+=item *
+
+If you use the form C<\N{I<character name>}>, the L<charnames> module
+gets automatically loaded. This may not be suitable for the test level
+you are doing.
+
+=back
+
+If you are testing locales (see L<perllocale>), there are helper
+functions in F<t/loc_tools.pl> to enable you to see what locales there
+are on the current platform.
=head2 Special C<make test> targets
There are various special make targets that can be used to test Perl
-slightly differently than the standard "test" target. Not all them are
-expected to give a 100% success rate. Many of them have several
+slightly differently than the standard "test" target. Not all them are
+expected to give a 100% success rate. Many of them have several
aliases, and many of them are not available on certain operating
systems.
This runs some basic sanity tests on the source tree and helps catch
basic errors before you submit a patch.
-=item * coretest
-
-Run F<perl> on all core tests (F<t/*> and F<lib/[a-z]*> pragma tests).
-
-(Not available on Win32)
-
-=item * test.deparse
-
-Run all the tests through L<B::Deparse>. Not all tests will succeed.
-
-(Not available on Win32)
-
-=item * test.taintwarn
-
-Run all tests with the B<-t> command-line switch. Not all tests are
-expected to succeed (until they're specifically fixed, of course).
-
-(Not available on Win32)
-
=item * minitest
Run F<miniperl> on F<t/base>, F<t/comp>, F<t/cmd>, F<t/run>, F<t/io>,
F<t/op>, F<t/uni> and F<t/mro> tests.
-=item * test.valgrind check.valgrind utest.valgrind ucheck.valgrind
+=item * test.valgrind check.valgrind
(Only in Linux) Run all the tests using the memory leak + naughty
-memory access tool "valgrind". The log files will be named
+memory access tool "valgrind". The log files will be named
F<testname.valgrind>.
-=item * test.torture torturetest
-
-Run all the usual tests and some extra tests. As of Perl 5.8.0, the only
-extra tests are Abigail's JAPHs, F<t/japh/abigail.t>.
-
-You can also run the torture test with F<t/harness> by giving
-C<-torture> argument to F<t/harness>.
-
-=item * utest ucheck test.utf8 check.utf8
-
-Run all the tests with -Mutf8. Not all tests will succeed.
-
-(Not available on Win32)
-
-=item * minitest.utf16 test.utf16
-
-Runs the tests with UTF-16 encoded scripts, encoded with different
-versions of this encoding.
-
-C<make utest.utf16> runs the test suite with a combination of C<-utf8>
-and C<-utf16> arguments to F<t/TEST>.
-
-(Not available on Win32)
-
=item * test_harness
Run the test suite with the F<t/harness> controlling program, instead
-of F<t/TEST>. F<t/harness> is more sophisticated, and uses the
+of F<t/TEST>. F<t/harness> is more sophisticated, and uses the
L<Test::Harness> module, thus using this test target supposes that perl
-mostly works. The main advantage for our purposes is that it prints a
-detailed summary of failed tests at the end. Also, unlike F<t/TEST>, it
-doesn't redirect stderr to stdout.
+mostly works. The main advantage for our purposes is that it prints a
+detailed summary of failed tests at the end. Also, unlike F<t/TEST>,
+it doesn't redirect stderr to stdout.
Note that under Win32 F<t/harness> is always used instead of F<t/TEST>,
so there is no special "test_harness" target.
Under Win32's "test" target you may use the TEST_SWITCHES and
TEST_FILES environment variables to control the behaviour of
-F<t/harness>. This means you can say
+F<t/harness>. This means you can say
nmake test TEST_FILES="op/*.t"
nmake test TEST_SWITCHES="-torture" TEST_FILES="op/*.t"
=head2 Parallel tests
The core distribution can now run its regression tests in parallel on
-Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS>
+Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS>
in your environment to the number of tests to run in parallel, and run
-C<make test_harness>. On a Bourne-like shell, this can be done as
+C<make test_harness>. On a Bourne-like shell, this can be done as
TEST_JOBS=3 make test_harness # Run 3 tests in parallel
non-conflicting test scripts itself, and there is no standard interface
to C<make> utilities to interact with their job schedulers.
-Note that currently some test scripts may fail when run in parallel (most
-notably C<ext/IO/t/io_dir.t>). If necessary, run just the failing scripts
-again sequentially and see if the failures go away.
+Note that currently some test scripts may fail when run in parallel
+(most notably F<dist/IO/t/io_dir.t>). If necessary, run just the
+failing scripts again sequentially and see if the failures go away.
=head2 Running tests by hand
-You can run part of the test suite by hand by using one of the following
-commands from the F<t/> directory:
+You can run part of the test suite by hand by using one of the
+following commands from the F<t/> directory:
./perl -I../lib TEST list-of-.t-files
=head2 Using F<t/harness> for testing
-If you use C<harness> for testing, you have several command line options
-available to you. The arguments are as follows, and are in the order
-that they must appear if used together.
+If you use C<harness> for testing, you have several command line
+options available to you. The arguments are as follows, and are in the
+order that they must appear if used together.
harness -v -torture -re=pattern LIST OF FILES TO TEST
harness -v -torture -re LIST OF PATTERNS TO MATCH
If C<LIST OF FILES TO TEST> is omitted, the file list is obtained from
-the manifest. The file list may include shell wildcards which will be
+the manifest. The file list may include shell wildcards which will be
expanded out.
=over 4
=item * -re=PATTERN
-Filter the file list so that all the test files run match PATTERN. Note
-that this form is distinct from the B<-re LIST OF PATTERNS> form below
-in that it allows the file list to be provided as well.
+Filter the file list so that all the test files run match PATTERN.
+Note that this form is distinct from the B<-re LIST OF PATTERNS> form
+below in that it allows the file list to be provided as well.
=item * -re LIST OF PATTERNS
Filter the file list so that all the test files run match
-/(LIST|OF|PATTERNS)/. Note that with this form the patterns are joined
+/(LIST|OF|PATTERNS)/. Note that with this form the patterns are joined
by '|' and you cannot supply a list of files, instead the test files
are obtained from the MANIFEST.
=item * PERL_CORE=1
indicates that we're running this test as part of the perl core test
-suite. This is useful for modules that have a dual life on CPAN.
+suite. This is useful for modules that have a dual life on CPAN.
=item * PERL_DESTRUCT_LEVEL=2
=item * PERL_SKIP_TTY_TEST
-if set, tells to skip the tests that need a terminal. It's actually set
-automatically by the Makefile, but can also be forced artificially by
-running 'make test_notty'.
+if set, tells to skip the tests that need a terminal. It's actually
+set automatically by the Makefile, but can also be forced artificially
+by running 'make test_notty'.
=back
=item * PERL_TEST_Net_Ping
Setting this variable runs all the Net::Ping modules tests, otherwise
-some tests that interact with the outside world are skipped. See
+some tests that interact with the outside world are skipped. See
L<perl58delta>.
=item * PERL_TEST_NOVREXX
This sets a variable in op/numconvert.t.
+=item * PERL_TEST_MEMORY
+
+Setting this variable includes the tests in F<t/bigmem/>. This should
+be set to the number of gigabytes of memory available for testing, eg.
+C<PERL_TEST_MEMORY=4> indicates that tests that require 4GiB of
+available memory can be run safely.
+
=back
See also the documentation for the Test and Test::Harness modules, for
more environment variables that affect testing.
+=head2 Performance testing
+
+The file F<t/perf/benchmarks> contains snippets of perl code which are
+intended to be benchmarked across a range of perls by the
+F<Porting/bench.pl> tool. If you fix or enhance a performance issue, you
+may want to add a representative code sample to the file, then run
+F<bench.pl> against the previous and current perls to see what difference
+it has made, and whether anything else has slowed down as a consequence.
+
+The file F<t/perf/opcount.t> is designed to test whether a particular
+code snippet has been compiled into an optree containing specified
+numbers of particular op types. This is good for testing whether
+optimisations which alter ops, such as converting an C<aelem> op into an
+C<aelemfast> op, are really doing that.
+
+The files F<t/perf/speed.t> and F<t/re/speed.t> are designed to test
+things that run thousands of times slower if a particular optimisation
+is broken (for example, the utf8 length cache on long utf8 strings).
+Add a test that will take a fraction of a second normally, and minutes
+otherwise, causing the test file to time out on failure.
+
+=head2 Building perl at older commits
+
+In the course of hacking on the Perl core distribution, you may have occasion
+to configure, build and test perl at an old commit. Sometimes C<make> will
+fail during this process. If that happens, you may be able to salvage the
+situation by using the Devel::PatchPerl library from CPAN (not included in the
+core) to bring the source code at that commit to a buildable state.
+
+Here's a real world example, taken from work done to resolve
+L<perl #72414|https://rt.perl.org/Ticket/Display.html?id=72414>.
+Use of F<Porting/bisect.pl> had identified commit
+C<ba77e4cc9d1ceebf472c9c5c18b2377ee47062e6> as the commit in which a bug was
+corrected. To confirm, a P5P developer wanted to configure and build perl at
+commit C<ba77e4c^> (presumably "bad") and then at C<ba77e4c> (presumably
+"good"). Normal configuration and build was attempted:
+
+ $ sh ./Configure -des -Dusedevel
+ $ make test_prep
+
+C<make>, however, failed with output (excerpted) like this:
+
+ cc -fstack-protector -L/usr/local/lib -o miniperl \
+ gv.o toke.o perly.o pad.o regcomp.o dump.o util.o \
+ mg.o reentr.o mro.o hv.o av.o run.o pp_hot.o sv.o \
+ pp.o scope.o pp_ctl.o pp_sys.o doop.o doio.o regexec.o \
+ utf8.o taint.o deb.o universal.o globals.o perlio.o \
+ perlapi.o numeric.o mathoms.o locale.o pp_pack.o pp_sort.o \
+ miniperlmain.o opmini.o perlmini.o
+ pp.o: In function `Perl_pp_pow':
+ pp.c:(.text+0x2db9): undefined reference to `pow'
+ ...
+ collect2: error: ld returned 1 exit status
+ makefile:348: recipe for target 'miniperl' failed
+ make: *** [miniperl] Error 1
+
+Another P5P contributor recommended installation and use of Devel::PatchPerl
+for this situation, first to determine the version of perl at the commit in
+question, then to patch the source code at that point to facilitate a build.
+
+ $ perl -MDevel::PatchPerl -e \
+ 'print Devel::PatchPerl->determine_version("/path/to/sourcecode"), "\n";'
+ 5.11.1
+ $ perl -MDevel::PatchPerl -e \
+ 'Devel::PatchPerl->patch_source("5.11.1", "/path/to/sourcecode");'
+
+Once the source was patched, C<./Configure> and C<make test_prep> were called
+and completed successfully, enabling confirmation of the findings in RT
+#72414.
+
=head1 MORE READING FOR GUTS HACKERS
To hack on the Perl guts, you'll need to read the following things:
=item * L<perlsource>
-An overview of the Perl source tree. This will help you find the files
+An overview of the Perl source tree. This will help you find the files
you're looking for.
=item * L<perlinterp>
=item * L<perlhacktut>
This document walks through the creation of a small patch to Perl's C
-code. If you're just getting started with Perl core hacking, this will
+code. If you're just getting started with Perl core hacking, this will
help you understand how it works.
=item * L<perlhacktips>
-More details on hacking the Perl core. This document focuses on lower
+More details on hacking the Perl core. This document focuses on lower
level details such as how to write tests, compilation issues,
portability, debugging, etc.
=item * L<perlguts>
This is of paramount importance, since it's the documentation of what
-goes where in the Perl source. Read it over a couple of times and it
+goes where in the Perl source. Read it over a couple of times and it
might start to make sense - don't worry if it doesn't yet, because the
best way to study it is to read it in conjunction with poking at Perl
source, and we'll do that later on.
A working knowledge of XSUB programming is incredibly useful for core
hacking; XSUBs use techniques drawn from the PP code, the portion of
-the guts that actually executes a Perl program. It's a lot gentler to
+the guts that actually executes a Perl program. It's a lot gentler to
learn those techniques from simple examples and explanation than from
the core itself.
is only useful to the pumpkin holder, but most of it applies to anyone
wanting to go about Perl development.
-=item * The perl5-porters FAQ
-
-This should be available from
-http://dev.perl.org/perl5/docs/p5p-faq.html . It contains hints on
-reading perl5-porters, information on how perl5-porters works and how
-Perl development in general works.
-
=back
=head1 CPAN TESTERS AND PERL SMOKERS
-The CPAN testers ( http://testers.cpan.org/ ) are a group of volunteers
+The CPAN testers ( L<http://testers.cpan.org/> ) are a group of volunteers
who test CPAN modules on a variety of platforms.
-Perl Smokers ( http://www.nntp.perl.org/group/perl.daily-build/ and
-http://www.nntp.perl.org/group/perl.daily-build.reports/ )
+Perl Smokers ( L<http://www.nntp.perl.org/group/perl.daily-build/> and
+L<http://www.nntp.perl.org/group/perl.daily-build.reports/> )
automatically test Perl source releases on platforms with various
configurations.
-Both efforts welcome volunteers. In order to get involved in smoke
+Both efforts welcome volunteers. In order to get involved in smoke
testing of the perl itself visit
-L<http://search.cpan.org/dist/Test-Smoke/>. In order to start smoke
+L<http://search.cpan.org/dist/Test-Smoke/>. In order to start smoke
testing CPAN modules visit
L<http://search.cpan.org/dist/CPANPLUS-YACSmoke/> or
L<http://search.cpan.org/dist/minismokebox/> or
=item *
Do read the README associated with your operating system, e.g.
-README.aix on the IBM AIX OS. Don't hesitate to supply patches to that
+README.aix on the IBM AIX OS. Don't hesitate to supply patches to that
README if you find anything missing or changed over a new OS release.
=item *
Find an area of Perl that seems interesting to you, and see if you can
-work out how it works. Scan through the source, and step over it in the
-debugger. Play, poke, investigate, fiddle! You'll probably get to
+work out how it works. Scan through the source, and step over it in
+the debugger. Play, poke, investigate, fiddle! You'll probably get to
understand not just your chosen area but a much wider range of
F<perl>'s activity as well, and probably sooner than you'd think.
=head2 "The Road goes ever on and on, down from the door where it began."
If you can do these things, you've started on the long road to Perl
-porting. Thanks for wanting to help make Perl better - and happy
+porting. Thanks for wanting to help make Perl better - and happy
hacking!
=head2 Metaphoric Quotations
If you recognized the quote about the Road above, you're in luck.
Most software projects begin each file with a literal description of
-each file's purpose. Perl instead begins each with a literary allusion
+each file's purpose. Perl instead begins each with a literary allusion
to that file's purpose.
Like chapters in many books, all top-level Perl source files (along
-with a few others here and there) begin with an epigramic inscription
-that alludes, indirectly and metaphorically, to the material you're
-about to read.
+with a few others here and there) begin with an epigrammatic
+inscription that alludes, indirectly and metaphorically, to the
+material you're about to read.
Quotations are taken from writings of J.R.R. Tolkien pertaining to his
-Legendarium, almost always from I<The Lord of the Rings>. Chapters and
+Legendarium, almost always from I<The Lord of the Rings>. Chapters and
page numbers are given using the following editions:
=over 4
=item *
-I<The Hobbit>, by J.R.R. Tolkien. The hardcover, 70th-anniversary
+I<The Hobbit>, by J.R.R. Tolkien. The hardcover, 70th-anniversary
edition of 2007 was used, published in the UK by Harper Collins
Publishers and in the US by the Houghton Mifflin Company.
=item *
-I<The Lord of the Rings>, by J.R.R. Tolkien. The hardcover,
+I<The Lord of the Rings>, by J.R.R. Tolkien. The hardcover,
50th-anniversary edition of 2004 was used, published in the UK by
Harper Collins Publishers and in the US by the Houghton Mifflin
Company.
I<The Lays of Beleriand>, by J.R.R. Tolkien and published posthumously
by his son and literary executor, C.J.R. Tolkien, being the 3rd of the
-12 volumes in Christopher's mammoth I<History of Middle Earth>. Page
+12 volumes in Christopher's mammoth I<History of Middle Earth>. Page
numbers derive from the hardcover edition, first published in 1983 by
George Allen & Unwin; no page numbers changed for the special 3-volume
omnibus edition of 2002 or the various trade-paper editions, all again
Other JRRT books fair game for quotes would thus include I<The
Adventures of Tom Bombadil>, I<The Silmarillion>, I<Unfinished Tales>,
and I<The Tale of the Children of Hurin>, all but the first
-posthumously assembled by CJRT. But I<The Lord of the Rings> itself is
+posthumously assembled by CJRT. But I<The Lord of the Rings> itself is
perfectly fine and probably best to quote from, provided you can find a
suitable quote there.
to Perl, you should conform to this peculiar practice by yourself
selecting an appropriate quotation from Tolkien, retaining the original
spelling and punctuation and using the same format the rest of the
-quotes are in. Indirect and oblique is just fine; remember, it's a
+quotes are in. Indirect and oblique is just fine; remember, it's a
metaphor, so being meta is, after all, what it's for.
=head1 AUTHOR
This document was originally written by Nathan Torkington, and is
maintained by the perl5-porters mailing list.
-
https://perl5.git.perl.org / perl5.git / blobdiff