=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
via email.
If your changes are in a single git commit, run the following commands
-to write the file as a MIME attachment and send it with a meaningful
-subject:
+to generate the patch file and attach it to your bug report:
- % git format-patch -1 --attach
- % ./perl -Ilib utils/perlbug -s "[PATCH] $(
- git log -1 --oneline HEAD)" -f 0001-*.patch
+ % git format-patch -1
+ % ./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 it
will submit your patch via email.
-If your changes are in multiple commits, generate a patch file
-containing them all, and attach that:
+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 origin/blead --attach --stdout > patches
- % ./perl -Ilib utils/perlbug -f patches
+ % 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 overall and
-has "[PATCH]" at the beginning.
+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
+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:
"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
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>.
+found at L<https://github.com/Perl/perl5>.
=head2 Read access via rsync
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.
+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
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. If you think your patch is appropriate for the maintenance
branch (see L<perlpolicy/MAINTENANCE BRANCHES>), please explain why
when you submit it.
=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 *
=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
+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<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> and avoiding things like C<fork()>
-and C<system()> unless absolutely necessary.
+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
+
+=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
to C<make> utilities to interact with their job schedulers.
Note that currently some test scripts may fail when run in parallel
-(most notably F<ext/IO/t/io_dir.t>). If necessary, run just the
+(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
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:
=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.
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