1PERLPOLICY(1)          Perl Programmers Reference Guide          PERLPOLICY(1)
2
3
4

NAME

6       perlpolicy - Various and sundry policies and commitments related to the
7       Perl core
8

DESCRIPTION

10       This document is the master document which records all written policies
11       about how the Perl 5 Porters collectively develop and maintain the Perl
12       core.
13

GOVERNANCE

15   Perl 5 Porters
16       Subscribers to perl5-porters (the porters themselves) come in several
17       flavours.  Some are quiet curious lurkers, who rarely pitch in and
18       instead watch the ongoing development to ensure they're forewarned of
19       new changes or features in Perl.  Some are representatives of vendors,
20       who are there to make sure that Perl continues to compile and work on
21       their platforms.  Some patch any reported bug that they know how to
22       fix, some are actively patching their pet area (threads, Win32, the
23       regexp -engine), while others seem to do nothing but complain.  In
24       other words, it's your usual mix of technical people.
25
26       Among these people are the core Perl team.  These are trusted
27       volunteers involved in the ongoing development of the Perl language and
28       interpreter.  They are not required to be language developers or
29       committers.
30
31       Over this group of porters presides Larry Wall.  He has the final word
32       in what does and does not change in any of the Perl programming
33       languages.  These days, Larry spends most of his time on Raku, while
34       Perl 5 is shepherded by a steering council of porters responsible for
35       deciding what goes into each release and ensuring that releases happen
36       on a regular basis.
37
38       Larry sees Perl development along the lines of the US government:
39       there's the Legislature (the porters, represented by the core team),
40       the Executive branch (the steering council), and the Supreme Court
41       (Larry).  The legislature can discuss and submit patches to the
42       executive branch all they like, but the executive branch is free to
43       veto them.  Rarely, the Supreme Court will side with the executive
44       branch over the legislature, or the legislature over the executive
45       branch.  Mostly, however, the legislature and the executive branch are
46       supposed to get along and work out their differences without
47       impeachment or court cases.
48
49       You might sometimes see reference to Rule 1 and Rule 2.  Larry's power
50       as Supreme Court is expressed in The Rules:
51
52       1.  Larry is always by definition right about how Perl should behave.
53           This means he has final veto power on the core functionality.
54
55       2.  Larry is allowed to change his mind about any matter at a later
56           date, regardless of whether he previously invoked Rule 1.
57
58       Got that?  Larry is always right, even when he was wrong.  It's rare to
59       see either Rule exercised, but they are often alluded to.
60
61       For the specifics on how the members of the core team and steering
62       council are elected or rotated, consult perlgov, which spells it all
63       out in detail.
64

MAINTENANCE AND SUPPORT

66       Perl 5 is developed by a community, not a corporate entity. Every
67       change contributed to the Perl core is the result of a donation.
68       Typically, these donations are contributions of code or time by
69       individual members of our community. On occasion, these donations come
70       in the form of corporate or organizational sponsorship of a particular
71       individual or project.
72
73       As a volunteer organization, the commitments we make are heavily
74       dependent on the goodwill and hard work of individuals who have no
75       obligation to contribute to Perl.
76
77       That being said, we value Perl's stability and security and have long
78       had an unwritten covenant with the broader Perl community to support
79       and maintain releases of Perl.
80
81       This document codifies the support and maintenance commitments that the
82       Perl community should expect from Perl's developers:
83
84       •   We "officially" support the two most recent stable release series.
85           5.30.x and earlier are now out of support.  As of the release of
86           5.36.0, we will "officially" end support for Perl 5.32.x, other
87           than providing security updates as described below.
88
89       •   To the best of our ability, we will attempt to fix critical issues
90           in the two most recent stable 5.x release series.  Fixes for the
91           current release series take precedence over fixes for the previous
92           release series.
93
94       •   To the best of our ability, we will provide "critical" security
95           patches / releases for any major version of Perl whose 5.x.0
96           release was within the past three years.  We can only commit to
97           providing these for the most recent .y release in any 5.x.y series.
98
99       •   We will not provide security updates or bug fixes for development
100           releases of Perl.
101
102       •   We encourage vendors to ship the most recent supported release of
103           Perl at the time of their code freeze.
104
105       •   As a vendor, you may have a requirement to backport security fixes
106           beyond our 3 year support commitment.  We can provide limited
107           support and advice to you as you do so and, where possible will try
108           to apply those patches to the relevant -maint branches in git,
109           though we may or may not choose to make numbered releases or
110           "official" patches available. See "SECURITY VULNERABILITY CONTACT
111           INFORMATION" in perlsec for details on how to begin that process.
112

BACKWARD COMPATIBILITY AND DEPRECATION

114       Our community has a long-held belief that backward-compatibility is a
115       virtue, even when the functionality in question is a design flaw.
116
117       We would all love to unmake some mistakes we've made over the past
118       decades.  Living with every design error we've ever made can lead to
119       painful stagnation.  Unwinding our mistakes is very, very difficult.
120       Doing so without actively harming our users is nearly impossible.
121
122       Lately, ignoring or actively opposing compatibility with earlier
123       versions of Perl has come into vogue.  Sometimes, a change is proposed
124       which wants to usurp syntax which previously had another meaning.
125       Sometimes, a change wants to improve previously-crazy semantics.
126
127       Down this road lies madness.
128
129       Requiring end-user programmers to change just a few language
130       constructs, even language constructs which no well-educated developer
131       would ever intentionally use is tantamount to saying "you should not
132       upgrade to a new release of Perl unless you have 100% test coverage and
133       can do a full manual audit of your codebase."  If we were to have tools
134       capable of reliably upgrading Perl source code from one version of Perl
135       to another, this concern could be significantly mitigated.
136
137       We want to ensure that Perl continues to grow and flourish in the
138       coming years and decades, but not at the expense of our user community.
139
140       Existing syntax and semantics should only be marked for destruction in
141       very limited circumstances.  If they are believed to be very rarely
142       used, stand in the way of actual improvement to the Perl language or
143       perl interpreter, and if affected code can be easily updated to
144       continue working, they may be considered for removal.  When in doubt,
145       caution dictates that we will favor backward compatibility.  When a
146       feature is deprecated, a statement of reasoning describing the decision
147       process will be posted, and a link to it will be provided in the
148       relevant perldelta documents.
149
150       Using a lexical pragma to enable or disable legacy behavior should be
151       considered when appropriate, and in the absence of any pragma legacy
152       behavior should be enabled.  Which backward-incompatible changes are
153       controlled implicitly by a 'use v5.x.y' is a decision which should be
154       made by the steering council in consultation with the community.
155
156       Historically, we've held ourselves to a far higher standard than
157       backward-compatibility -- bugward-compatibility.  Any accident of
158       implementation or unintentional side-effect of running some bit of code
159       has been considered to be a feature of the language to be defended with
160       the same zeal as any other feature or functionality.  No matter how
161       frustrating these unintentional features may be to us as we continue to
162       improve Perl, these unintentional features often deserve our
163       protection.  It is very important that existing software written in
164       Perl continue to work correctly.  If end-user developers have adopted a
165       bug as a feature, we need to treat it as such.
166
167       New syntax and semantics which don't break existing language constructs
168       and syntax have a much lower bar.  They merely need to prove themselves
169       to be useful, elegant, well designed, and well tested.  In most cases,
170       these additions will be marked as experimental for some time.  See
171       below for more on that.
172
173   Terminology
174       To make sure we're talking about the same thing when we discuss the
175       removal of features or functionality from the Perl core, we have
176       specific definitions for a few words and phrases.
177
178       experimental
179           If something in the Perl core is marked as experimental, we may
180           change its behaviour, deprecate or remove it without notice. While
181           we'll always do our best to smooth the transition path for users of
182           experimental features, you should contact the perl5-porters
183           mailinglist if you find an experimental feature useful and want to
184           help shape its future.
185
186           Experimental features must be experimental in two stable releases
187           before being marked non-experimental.  Experimental features will
188           only have their experimental status revoked when they no longer
189           have any design-changing bugs open against them and when they have
190           remained unchanged in behavior for the entire length of a
191           development cycle.  In other words, a feature present in v5.20.0
192           may be marked no longer experimental in v5.22.0 if and only if its
193           behavior is unchanged throughout all of v5.21.
194
195       deprecated
196           If something in the Perl core is marked as deprecated, we may
197           remove it from the core in the future, though we might not.
198           Generally, backward incompatible changes will have deprecation
199           warnings for two release cycles before being removed, but may be
200           removed after just one cycle if the risk seems quite low or the
201           benefits quite high.
202
203           As of Perl 5.12, deprecated features and modules warn the user as
204           they're used.  When a module is deprecated, it will also be made
205           available on CPAN.  Installing it from CPAN will silence
206           deprecation warnings for that module.
207
208           If you use a deprecated feature or module and believe that its
209           removal from the Perl core would be a mistake, please contact the
210           perl5-porters mailinglist and plead your case.  We don't deprecate
211           things without a good reason, but sometimes there's a
212           counterargument we haven't considered.  Historically, we did not
213           distinguish between "deprecated" and "discouraged" features.
214
215       discouraged
216           From time to time, we may mark language constructs and features
217           which we consider to have been mistakes as discouraged.
218           Discouraged features aren't currently candidates for removal, but
219           we may later deprecate them if they're found to stand in the way of
220           a significant improvement to the Perl core.
221
222       removed
223           Once a feature, construct or module has been marked as deprecated,
224           we may remove it from the Perl core.  Unsurprisingly, we say we've
225           removed these things.  When a module is removed, it will no longer
226           ship with Perl, but will continue to be available on CPAN.
227

MAINTENANCE BRANCHES

229       New releases of maintenance branches should only contain changes that
230       fall into one of the "acceptable" categories set out below, but must
231       not contain any changes that fall into one of the "unacceptable"
232       categories.  (For example, a fix for a crashing bug must not be
233       included if it breaks binary compatibility.)
234
235       It is not necessary to include every change meeting these criteria, and
236       in general the focus should be on addressing security issues, crashing
237       bugs, regressions and serious installation issues.  The temptation to
238       include a plethora of minor changes that don't affect the installation
239       or execution of perl (e.g. spelling corrections in documentation)
240       should be resisted in order to reduce the overall risk of overlooking
241       something.  The intention is to create maintenance releases which are
242       both worthwhile and which users can have full confidence in the
243       stability of.  (A secondary concern is to avoid burning out the maint-
244       release manager or overwhelming other committers voting on changes to
245       be included (see "Getting changes into a maint branch" below).)
246
247       The following types of change may be considered acceptable, as long as
248       they do not also fall into any of the "unacceptable" categories set out
249       below:
250
251       •   Patches that fix CVEs or security issues.  These changes should be
252           passed using the security reporting mechanism rather than applied
253           directly; see "SECURITY VULNERABILITY CONTACT INFORMATION" in
254           perlsec.
255
256       •   Patches that fix crashing bugs, assertion failures and memory
257           corruption but which do not otherwise change perl's functionality
258           or negatively impact performance.
259
260       •   Patches that fix regressions in perl's behavior relative to
261           previous releases, no matter how old the regression, since some
262           people may upgrade from very old versions of perl to the latest
263           version.
264
265       •   Patches that fix bugs in features that were new in the
266           corresponding 5.x.0 stable release.
267
268       •   Patches that fix anything which prevents or seriously impacts the
269           build or installation of perl.
270
271       •   Portability fixes, such as changes to Configure and the files in
272           the hints/ folder.
273
274       •   Minimal patches that fix platform-specific test failures.
275
276       •   Documentation updates that correct factual errors, explain
277           significant bugs or deficiencies in the current implementation, or
278           fix broken markup.
279
280       •   Updates to dual-life modules should consist of minimal patches to
281           fix crashing bugs or security issues (as above).  Any changes made
282           to dual-life modules for which CPAN is canonical should be
283           coordinated with the upstream author.
284
285       The following types of change are NOT acceptable:
286
287       •   Patches that break binary compatibility.  (Please talk to the
288           steering council.)
289
290       •   Patches that add or remove features.
291
292       •   Patches that add new warnings or errors or deprecate features.
293
294       •   Ports of Perl to a new platform, architecture or OS release that
295           involve changes to the implementation.
296
297       •   New versions of dual-life modules should NOT be imported into
298           maint.  Those belong in the next stable series.
299
300       If there is any question about whether a given patch might merit
301       inclusion in a maint release, then it almost certainly should not be
302       included.
303
304   Getting changes into a maint branch
305       Historically, only the single-person project manager cherry-picked
306       changes from bleadperl into maintperl.  This has scaling problems.  At
307       the same time, maintenance branches of stable versions of Perl need to
308       be treated with great care.  To that end, as of Perl 5.12, we have a
309       new process for maint branches.
310
311       Any committer may cherry-pick any commit from blead to a maint branch
312       by first adding an entry to the relevant voting file in the maint-votes
313       branch announcing the commit as a candidate for back-porting, and then
314       waiting for at least two other committers to add their votes in support
315       of this (i.e. a total of at least three votes is required before a
316       commit may be back-ported).
317
318       Most of the work involved in both rounding up a suitable set of
319       candidate commits and cherry-picking those for which three votes have
320       been cast will be done by the maint branch release manager, but anyone
321       else is free to add other proposals if they're keen to ensure certain
322       fixes don't get overlooked or fear they already have been.
323
324       Other voting mechanisms may also be used instead (e.g. sending mail to
325       perl5-porters and at least two other committers responding to the list
326       giving their assent), as long as the same number of votes is gathered
327       in a transparent manner.  Specifically, proposals of which changes to
328       cherry-pick must be visible to everyone on perl5-porters so that the
329       views of everyone interested may be heard.
330
331       It is not necessary for voting to be held on cherry-picking perldelta
332       entries associated with changes that have already been cherry-picked,
333       nor for the maint-release manager to obtain votes on changes required
334       by the Porting/release_managers_guide.pod where such changes can be
335       applied by the means of cherry-picking from blead.
336

CONTRIBUTED MODULES

338   A Social Contract about Artistic Control
339       What follows is a statement about artistic control, defined as the
340       ability of authors of packages to guide the future of their code and
341       maintain control over their work.  It is a recognition that authors
342       should have control over their work, and that it is a responsibility of
343       the rest of the Perl community to ensure that they retain this control.
344       It is an attempt to document the standards to which we, as Perl
345       developers, intend to hold ourselves.  It is an attempt to write down
346       rough guidelines about the respect we owe each other as Perl
347       developers.
348
349       This statement is not a legal contract.  This statement is not a legal
350       document in any way, shape, or form.  Perl is distributed under the GNU
351       Public License and under the Artistic License; those are the precise
352       legal terms.  This statement isn't about the law or licenses.  It's
353       about community, mutual respect, trust, and good-faith cooperation.
354
355       We recognize that the Perl core, defined as the software distributed
356       with the heart of Perl itself, is a joint project on the part of all of
357       us.  From time to time, a script, module, or set of modules (hereafter
358       referred to simply as a "module") will prove so widely useful and/or so
359       integral to the correct functioning of Perl itself that it should be
360       distributed with the Perl core.  This should never be done without the
361       author's explicit consent, and a clear recognition on all parts that
362       this means the module is being distributed under the same terms as Perl
363       itself.  A module author should realize that inclusion of a module into
364       the Perl core will necessarily mean some loss of control over it, since
365       changes may occasionally have to be made on short notice or for
366       consistency with the rest of Perl.
367
368       Once a module has been included in the Perl core, however, everyone
369       involved in maintaining Perl should be aware that the module is still
370       the property of the original author unless the original author
371       explicitly gives up their ownership of it.  In particular:
372
373       •   The version of the module in the Perl core should still be
374           considered the work of the original author.  All patches, bug
375           reports, and so forth should be fed back to them.  Their
376           development directions should be respected whenever possible.
377
378       •   Patches may be applied by the steering council without the explicit
379           cooperation of the module author if and only if they are very
380           minor, time-critical in some fashion (such as urgent security
381           fixes), or if the module author cannot be reached.  Those patches
382           must still be given back to the author when possible, and if the
383           author decides on an alternate fix in their version, that fix
384           should be strongly preferred unless there is a serious problem with
385           it.  Any changes not endorsed by the author should be marked as
386           such, and the contributor of the change acknowledged.
387
388       •   The version of the module distributed with Perl should, whenever
389           possible, be the latest version of the module as distributed by the
390           author (the latest non-beta version in the case of public Perl
391           releases), although the steering council may hold off on upgrading
392           the version of the module distributed with Perl to the latest
393           version until the latest version has had sufficient testing.
394
395       In other words, the author of a module should be considered to have
396       final say on modifications to their module whenever possible (bearing
397       in mind that it's expected that everyone involved will work together
398       and arrive at reasonable compromises when there are disagreements).
399
400       As a last resort, however:
401
402       If the author's vision of the future of their module is sufficiently
403       different from the vision of the steering council and perl5-porters as
404       a whole so as to cause serious problems for Perl, the steering council
405       may choose to formally fork the version of the module in the Perl core
406       from the one maintained by the author.  This should not be done lightly
407       and should always if at all possible be done only after direct input
408       from Larry.  If this is done, it must then be made explicit in the
409       module as distributed with the Perl core that it is a forked version
410       and that while it is based on the original author's work, it is no
411       longer maintained by them.  This must be noted in both the
412       documentation and in the comments in the source of the module.
413
414       Again, this should be a last resort only.  Ideally, this should never
415       happen, and every possible effort at cooperation and compromise should
416       be made before doing this.  If it does prove necessary to fork a module
417       for the overall health of Perl, proper credit must be given to the
418       original author in perpetuity and the decision should be constantly re-
419       evaluated to see if a remerging of the two branches is possible down
420       the road.
421
422       In all dealings with contributed modules, everyone maintaining Perl
423       should keep in mind that the code belongs to the original author, that
424       they may not be on perl5-porters at any given time, and that a patch is
425       not official unless it has been integrated into the author's copy of
426       the module.  To aid with this, and with points #1, #2, and #3 above,
427       contact information for the authors of all contributed modules should
428       be kept with the Perl distribution.
429
430       Finally, the Perl community as a whole recognizes that respect for
431       ownership of code, respect for artistic control, proper credit, and
432       active effort to prevent unintentional code skew or communication gaps
433       is vital to the health of the community and Perl itself.  Members of a
434       community should not normally have to resort to rules and laws to deal
435       with each other, and this document, although it contains rules so as to
436       be clear, is about an attitude and general approach.  The first step in
437       any dispute should be open communication, respect for opposing views,
438       and an attempt at a compromise.  In nearly every circumstance nothing
439       more will be necessary, and certainly no more drastic measure should be
440       used until every avenue of communication and discussion has failed.
441

DOCUMENTATION

443       Perl's documentation is an important resource for our users. It's
444       incredibly important for Perl's documentation to be reasonably coherent
445       and to accurately reflect the current implementation.
446
447       Just as P5P collectively maintains the codebase, we collectively
448       maintain the documentation.  Writing a particular bit of documentation
449       doesn't give an author control of the future of that documentation.  At
450       the same time, just as source code changes should match the style of
451       their surrounding blocks, so should documentation changes.
452
453       Examples in documentation should be illustrative of the concept they're
454       explaining.  Sometimes, the best way to show how a language feature
455       works is with a small program the reader can run without modification.
456       More often, examples will consist of a snippet of code containing only
457       the "important" bits.  The definition of "important" varies from
458       snippet to snippet.  Sometimes it's important to declare "use strict"
459       and "use warnings", initialize all variables and fully catch every
460       error condition.  More often than not, though, those things obscure the
461       lesson the example was intended to teach.
462
463       As Perl is developed by a global team of volunteers, our documentation
464       often contains spellings which look funny to somebody.  Choice of
465       American/British/Other spellings is left as an exercise for the author
466       of each bit of documentation.  When patching documentation, try to
467       emulate the documentation around you, rather than changing the existing
468       prose.
469
470       In general, documentation should describe what Perl does "now" rather
471       than what it used to do.  It's perfectly reasonable to include notes in
472       documentation about how behaviour has changed from previous releases,
473       but, with very few exceptions, documentation isn't "dual-life" -- it
474       doesn't need to fully describe how all old versions used to work.
475

STANDARDS OF CONDUCT

477       The official forum for the development of perl is the perl5-porters
478       mailing list, mentioned above, and its bugtracker at GitHub.  Posting
479       to the list and the bugtracker is not a right: all participants in
480       discussion are expected to adhere to a standard of conduct.
481
482       •   Always be civil.
483
484       •   Heed the moderators.
485
486       Civility is simple: stick to the facts while avoiding demeaning
487       remarks, belittling other individuals, sarcasm, or a presumption of bad
488       faith. It is not enough to be factual.  You must also be civil.
489       Responding in kind to incivility is not acceptable.  If you relay
490       otherwise-unposted comments to the list from a third party, you take
491       responsibility for the content of those comments, and you must
492       therefore ensure that they are civil.
493
494       While civility is required, kindness is encouraged; if you have any
495       doubt about whether you are being civil, simply ask yourself, "Am I
496       being kind?" and aspire to that.
497
498       If the list moderators tell you that you are not being civil, carefully
499       consider how your words have appeared before responding in any way.
500       Were they kind?  You may protest, but repeated protest in the face of a
501       repeatedly reaffirmed decision is not acceptable.  Repeatedly
502       protesting about the moderators' decisions regarding a third party is
503       also unacceptable, as is continuing to initiate off-list contact with
504       the moderators about their decisions.
505
506       Unacceptable behavior will result in a public and clearly identified
507       warning.  A second instance of unacceptable behavior from the same
508       individual will result in removal from the mailing list and GitHub
509       issue tracker, for a period of one calendar month.  The rationale for
510       this is to provide an opportunity for the person to change the way they
511       act.
512
513       After the time-limited ban has been lifted, a third instance of
514       unacceptable behavior will result in a further public warning.  A
515       fourth or subsequent instance will result in an indefinite ban.  The
516       rationale is that, in the face of an apparent refusal to change
517       behavior, we must protect other community members from future
518       unacceptable actions.  The moderators may choose to lift an indefinite
519       ban if the person in question affirms they will not transgress again.
520
521       Removals, like warnings, are public.
522
523       The list of moderators will be public knowledge.  At present, it is:
524       Karen Etheridge, Neil Bowers, Nicholas Clark, Ricardo Signes, Todd
525       Rinaldo.
526

CREDITS

528       "Social Contract about Contributed Modules" originally by Russ Allbery
529       <rra@stanford.edu> and the perl5-porters.
530
531
532
533perl v5.38.2                      2023-11-30                     PERLPOLICY(1)
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