1CPAN::Meta::Spec(3) User Contributed Perl Documentation CPAN::Meta::Spec(3)
2
6 CPAN::Meta::Spec - specification for CPAN distribution metadata
7
9 version 2.150010
10
12 my $distmeta = {
13 name => 'Module-Build',
14 abstract => 'Build and install Perl modules',
15 description => "Module::Build is a system for "
16 . "building, testing, and installing Perl modules. "
17 . "It is meant to ... blah blah blah ...",
18 version => '0.36',
19 release_status => 'stable',
20 author => [
21 'Ken Williams <kwilliams@cpan.org>',
22 'Module-Build List <module-build@perl.org>', # additional contact
23 ],
24 license => [ 'perl_5' ],
25 prereqs => {
26 runtime => {
27 requires => {
28 'perl' => '5.006',
29 'ExtUtils::Install' => '0',
30 'File::Basename' => '0',
31 'File::Compare' => '0',
32 'IO::File' => '0',
33 },
34 recommends => {
35 'Archive::Tar' => '1.00',
36 'ExtUtils::Install' => '0.3',
37 'ExtUtils::ParseXS' => '2.02',
38 },
39 },
40 build => {
41 requires => {
42 'Test::More' => '0',
43 },
44 }
45 },
46 resources => {
47 license => ['http://dev.perl.org/licenses/'],
48 },
49 optional_features => {
50 domination => {
51 description => 'Take over the world',
52 prereqs => {
53 develop => { requires => { 'Genius::Evil' => '1.234' } },
54 runtime => { requires => { 'Machine::Weather' => '2.0' } },
55 },
56 },
57 },
58 dynamic_config => 1,
59 keywords => [ qw/ toolchain cpan dual-life / ],
60 'meta-spec' => {
61 version => '2',
62 url => 'https://metacpan.org/pod/CPAN::Meta::Spec',
63 },
64 generated_by => 'Module::Build version 0.36',
65 };
66
68 This document describes version 2 of the CPAN distribution metadata
69 specification, also known as the "CPAN Meta Spec".
70 Revisions of this specification for typo corrections and prose
72 clarifications may be issued as CPAN::Meta::Spec 2.x. These revisions
73 will never change semantics or add or remove specified behavior.
74 Distribution metadata describe important properties of Perl
76 distributions. Distribution building tools like Module::Build,
77 Module::Install, ExtUtils::MakeMaker or Dist::Zilla should create a
78 metadata file in accordance with this specification and include it with
79 the distribution for use by automated tools that index, examine,
80 package or install Perl distributions.
81
83 distribution
84 This is the primary object described by the metadata. In the
85 context of this document it usually refers to a collection of
86 modules, scripts, and/or documents that are distributed together
87 for other developers to use. Examples of distributions are
88 "Class-Container", "libwww-perl", or "DBI".
89 module
91 This refers to a reusable library of code contained in a single
92 file. Modules usually contain one or more packages and are often
93 referred to by the name of a primary package that can be mapped to
94 the file name. For example, one might refer to "File::Spec" instead
95 of File/Spec.pm
96 package
98 This refers to a namespace declared with the Perl "package"
99 statement. In Perl, packages often have a version number property
100 given by the $VERSION variable in the namespace.
101 consumer
103 This refers to code that reads a metadata file, deserializes it
104 into a data structure in memory, or interprets a data structure of
105 metadata elements.
106 producer
108 This refers to code that constructs a metadata data structure,
109 serializes into a bytestream and/or writes it to disk.
110 must, should, may, etc.
112 These terms are interpreted as described in IETF RFC 2119.
113
115 Fields in the "STRUCTURE" section describe data elements, each of which
116 has an associated data type as described herein. There are four
117 primitive types: Boolean, String, List and Map. Other types are
118 subtypes of primitives and define compound data structures or define
119 constraints on the values of a data element.
120 Boolean
122 A Boolean is used to provide a true or false value. It must be
123 represented as a defined value that is either "1" or "0" or stringifies
124 to those values.
125 String
127 A String is data element containing a non-zero length sequence of
128 Unicode characters, such as an ordinary Perl scalar that is not a
129 reference.
130 List
132 A List is an ordered collection of zero or more data elements.
133 Elements of a List may be of mixed types.
134 Producers must represent List elements using a data structure which
136 unambiguously indicates that multiple values are possible, such as a
137 reference to a Perl array (an "arrayref").
138 Consumers expecting a List must consider a String as equivalent to a
140 List of length 1.
141 Map
143 A Map is an unordered collection of zero or more data elements
144 ("values"), indexed by associated String elements ("keys"). The Map's
145 value elements may be of mixed types.
146 License String
148 A License String is a subtype of String with a restricted set of
149 values. Valid values are described in detail in the description of the
150 "license" field.
151 URL
153 URL is a subtype of String containing a Uniform Resource Locator or
154 Identifier. [ This type is called URL and not URI for historical
155 reasons. ]
156 Version
158 A Version is a subtype of String containing a value that describes the
159 version number of packages or distributions. Restrictions on format
160 are described in detail in the "Version Formats" section.
161 Version Range
163 The Version Range type is a subtype of String. It describes a range of
164 Versions that may be present or installed to fulfill prerequisites. It
165 is specified in detail in the "Version Ranges" section.
166
168 The metadata structure is a data element of type Map. This section
169 describes valid keys within the Map.
170 Any keys not described in this specification document (whether top-
172 level or within compound data structures described herein) are
173 considered custom keys and must begin with an "x" or "X" and be
174 followed by an underscore; i.e. they must match the pattern:
175 "qr{\Ax_}i". If a custom key refers to a compound data structure,
176 subkeys within it do not need an "x_" or "X_" prefix.
177 Consumers of metadata may ignore any or all custom keys. All other
179 keys not described herein are invalid and should be ignored by
180 consumers. Producers must not generate or output invalid keys.
181 For each key, an example is provided followed by a description. The
183 description begins with the version of spec in which the key was added
184 or in which the definition was modified, whether the key is required or
185 optional and the data type of the corresponding data element. These
186 items are in parentheses, brackets and braces, respectively.
187 If a data type is a Map or Map subtype, valid subkeys will be described
189 as well.
190 Some fields are marked Deprecated. These are shown for historical
192 context and must not be produced in or consumed from any metadata
193 structure of version 2 or higher.
194 REQUIRED FIELDS
196 abstract
197 Example:
199 abstract => 'Build and install Perl modules'
201 (Spec 1.2) [required] {String}
203 This is a short description of the purpose of the distribution.
205 author
207 Example:
209 author => [ 'Ken Williams <kwilliams@cpan.org>' ]
211 (Spec 1.2) [required] {List of one or more Strings}
213 This List indicates the person(s) to contact concerning the
215 distribution. The preferred form of the contact string is:
216 contact-name <email-address>
218 This field provides a general contact list independent of other
220 structured fields provided within the "resources" field, such as
221 "bugtracker". The addressee(s) can be contacted for any purpose
222 including but not limited to (security) problems with the distribution,
223 questions about the distribution or bugs in the distribution.
224 A distribution's original author is usually the contact listed within
226 this field. Co-maintainers, successor maintainers or mailing lists
227 devoted to the distribution may also be listed in addition to or
228 instead of the original author.
229 dynamic_config
231 Example:
233 dynamic_config => 1
235 (Spec 2) [required] {Boolean}
237 A boolean flag indicating whether a Build.PL or Makefile.PL (or
239 similar) must be executed to determine prerequisites.
240 This field should be set to a true value if the distribution performs
242 some dynamic configuration (asking questions, sensing the environment,
243 etc.) as part of its configuration. This field should be set to a
244 false value to indicate that prerequisites included in metadata may be
245 considered final and valid for static analysis.
246 Note: when this field is true, post-configuration prerequisites are not
248 guaranteed to bear any relation whatsoever to those stated in the
249 metadata, and relying on them doing so is an error. See also
250 "Prerequisites for dynamically configured distributions" in the
251 implementors' notes.
252 This field explicitly does not indicate whether installation may be
254 safely performed without using a Makefile or Build file, as there may
255 be special files to install or custom installation targets (e.g. for
256 dual-life modules that exist on CPAN as well as in the Perl core).
257 This field only defines whether or not prerequisites are exactly as
258 given in the metadata.
259 generated_by
261 Example:
263 generated_by => 'Module::Build version 0.36'
265 (Spec 1.0) [required] {String}
267 This field indicates the tool that was used to create this metadata.
269 There are no defined semantics for this field, but it is traditional to
270 use a string in the form "Generating::Package version 1.23" or the
271 author's name, if the file was generated by hand.
272 license
274 Example:
276 license => [ 'perl_5' ]
278 license => [ 'apache_2_0', 'mozilla_1_0' ]
280 (Spec 2) [required] {List of one or more License Strings}
282 One or more licenses that apply to some or all of the files in the
284 distribution. If multiple licenses are listed, the distribution
285 documentation should be consulted to clarify the interpretation of
286 multiple licenses.
287 The following list of license strings are valid:
289 string description
291 ------------- -----------------------------------------------
292 agpl_3 GNU Affero General Public License, Version 3
293 apache_1_1 Apache Software License, Version 1.1
294 apache_2_0 Apache License, Version 2.0
295 artistic_1 Artistic License, (Version 1)
296 artistic_2 Artistic License, Version 2.0
297 bsd BSD License (three-clause)
298 freebsd FreeBSD License (two-clause)
299 gfdl_1_2 GNU Free Documentation License, Version 1.2
300 gfdl_1_3 GNU Free Documentation License, Version 1.3
301 gpl_1 GNU General Public License, Version 1
302 gpl_2 GNU General Public License, Version 2
303 gpl_3 GNU General Public License, Version 3
304 lgpl_2_1 GNU Lesser General Public License, Version 2.1
305 lgpl_3_0 GNU Lesser General Public License, Version 3.0
306 mit MIT (aka X11) License
307 mozilla_1_0 Mozilla Public License, Version 1.0
308 mozilla_1_1 Mozilla Public License, Version 1.1
309 openssl OpenSSL License
310 perl_5 The Perl 5 License (Artistic 1 & GPL 1 or later)
311 qpl_1_0 Q Public License, Version 1.0
312 ssleay Original SSLeay License
313 sun Sun Internet Standards Source License (SISSL)
314 zlib zlib License
315 The following license strings are also valid and indicate other
317 licensing not described above:
318 string description
320 ------------- -----------------------------------------------
321 open_source Other Open Source Initiative (OSI) approved license
322 restricted Requires special permission from copyright holder
323 unrestricted Not an OSI approved license, but not restricted
324 unknown License not provided in metadata
325 All other strings are invalid in the license field.
327 meta-spec
329 Example:
331 'meta-spec' => {
333 version => '2',
334 url => 'http://search.cpan.org/perldoc?CPAN::Meta::Spec',
335 }
336 (Spec 1.2) [required] {Map}
338 This field indicates the version of the CPAN Meta Spec that should be
340 used to interpret the metadata. Consumers must check this key as soon
341 as possible and abort further metadata processing if the meta-spec
342 version is not supported by the consumer.
343 The following keys are valid, but only "version" is required.
345 version
347 This subkey gives the integer Version of the CPAN Meta Spec against
348 which the document was generated.
349 url This is a URL of the metadata specification document corresponding
351 to the given version. This is strictly for human-consumption and
352 should not impact the interpretation of the document.
353 For the version 2 spec, either of these are recommended:
355 • "https://metacpan.org/pod/CPAN::Meta::Spec"
357 • "http://search.cpan.org/perldoc?CPAN::Meta::Spec"
359 name
361 Example:
363 name => 'Module-Build'
365 (Spec 1.0) [required] {String}
367 This field is the name of the distribution. This is often created by
369 taking the "main package" in the distribution and changing "::" to "-",
370 but the name may be completely unrelated to the packages within the
371 distribution. For example, LWP::UserAgent is distributed as part of
372 the distribution name "libwww-perl".
373 release_status
375 Example:
377 release_status => 'stable'
379 (Spec 2) [required] {String}
381 This field provides the release status of this distribution. If the
383 "version" field contains an underscore character, then "release_status"
384 must not be "stable."
385 The "release_status" field must have one of the following values:
387 stable
389 This indicates an ordinary, "final" release that should be indexed
390 by PAUSE or other indexers.
391 testing
393 This indicates a "beta" release that is substantially complete, but
394 has an elevated risk of bugs and requires additional testing. The
395 distribution should not be installed over a stable release without
396 an explicit request or other confirmation from a user. This
397 release status may also be used for "release candidate" versions of
398 a distribution.
399 unstable
401 This indicates an "alpha" release that is under active development,
402 but has been released for early feedback or testing and may be
403 missing features or may have serious bugs. The distribution should
404 not be installed over a stable release without an explicit request
405 or other confirmation from a user.
406 Consumers may use this field to determine how to index the distribution
408 for CPAN or other repositories in addition to or in replacement of
409 heuristics based on version number or file name.
410 version
412 Example:
414 version => '0.36'
416 (Spec 1.0) [required] {Version}
418 This field gives the version of the distribution to which the metadata
420 structure refers.
421 OPTIONAL FIELDS
423 description
424 Example:
426 description => "Module::Build is a system for "
428 . "building, testing, and installing Perl modules. "
429 . "It is meant to ... blah blah blah ...",
430 (Spec 2) [optional] {String}
432 A longer, more complete description of the purpose or intended use of
434 the distribution than the one provided by the "abstract" key.
435 keywords
437 Example:
439 keywords => [ qw/ toolchain cpan dual-life / ]
441 (Spec 1.1) [optional] {List of zero or more Strings}
443 A List of keywords that describe this distribution. Keywords must not
445 include whitespace.
446 no_index
448 Example:
450 no_index => {
452 file => [ 'My/Module.pm' ],
453 directory => [ 'My/Private' ],
454 package => [ 'My::Module::Secret' ],
455 namespace => [ 'My::Module::Sample' ],
456 }
457 (Spec 1.2) [optional] {Map}
459 This Map describes any files, directories, packages, and namespaces
461 that are private to the packaging or implementation of the distribution
462 and should be ignored by indexing or search tools. Note that this is a
463 list of exclusions, and the spec does not define what to include - see
464 "Indexing distributions a la PAUSE" in the implementors notes for more
465 information.
466 Valid subkeys are as follows:
468 file
470 A List of relative paths to files. Paths must be specified with
471 unix conventions.
472 directory
474 A List of relative paths to directories. Paths must be specified
475 with unix conventions.
476 [ Note: previous editions of the spec had "dir" instead of
478 "directory" ]
479 package
481 A List of package names.
482 namespace
484 A List of package namespaces, where anything below the namespace
485 must be ignored, but not the namespace itself.
486 In the example above for "no_index", "My::Module::Sample::Foo"
488 would be ignored, but "My::Module::Sample" would not.
489 optional_features
491 Example:
493 optional_features => {
495 sqlite => {
496 description => 'Provides SQLite support',
497 prereqs => {
498 runtime => {
499 requires => {
500 'DBD::SQLite' => '1.25'
501 }
502 }
503 }
504 }
505 }
506 (Spec 2) [optional] {Map}
508 This Map describes optional features with incremental prerequisites.
510 Each key of the "optional_features" Map is a String used to identify
511 the feature and each value is a Map with additional information about
512 the feature. Valid subkeys include:
513 description
515 This is a String describing the feature. Every optional feature
516 should provide a description
517 prereqs
519 This entry is required and has the same structure as that of the
520 "prereqs" key. It provides a list of package requirements that
521 must be satisfied for the feature to be supported or enabled.
522 There is one crucial restriction: the prereqs of an optional
524 feature must not include "configure" phase prereqs.
525 Consumers must not include optional features as prerequisites without
527 explicit instruction from users (whether via interactive prompting, a
528 function parameter or a configuration value, etc. ).
529 If an optional feature is used by a consumer to add additional
531 prerequisites, the consumer should merge the optional feature
532 prerequisites into those given by the "prereqs" key using the same
533 semantics. See "Merging and Resolving Prerequisites" for details on
534 merging prerequisites.
535 Suggestion for disuse: Because there is currently no way for a
537 distribution to specify a dependency on an optional feature of another
538 dependency, the use of "optional_feature" is discouraged. Instead,
539 create a separate, installable distribution that ensures the desired
540 feature is available. For example, if "Foo::Bar" has a "Baz" feature,
541 release a separate "Foo-Bar-Baz" distribution that satisfies
542 requirements for the feature.
543 prereqs
545 Example:
547 prereqs => {
549 runtime => {
550 requires => {
551 'perl' => '5.006',
552 'File::Spec' => '0.86',
553 'JSON' => '2.16',
554 },
555 recommends => {
556 'JSON::XS' => '2.26',
557 },
558 suggests => {
559 'Archive::Tar' => '0',
560 },
561 },
562 build => {
563 requires => {
564 'Alien::SDL' => '1.00',
565 },
566 },
567 test => {
568 recommends => {
569 'Test::Deep' => '0.10',
570 },
571 }
572 }
573 (Spec 2) [optional] {Map}
575 This is a Map that describes all the prerequisites of the distribution.
577 The keys are phases of activity, such as "configure", "build", "test"
578 or "runtime". Values are Maps in which the keys name the type of
579 prerequisite relationship such as "requires", "recommends", or
580 "suggests" and the value provides a set of prerequisite relations. The
581 set of relations must be specified as a Map of package names to version
582 ranges.
583 The full definition for this field is given in the "Prereq Spec"
585 section.
586 provides
588 Example:
590 provides => {
592 'Foo::Bar' => {
593 file => 'lib/Foo/Bar.pm',
594 version => '0.27_02',
595 },
596 'Foo::Bar::Blah' => {
597 file => 'lib/Foo/Bar/Blah.pm',
598 },
599 'Foo::Bar::Baz' => {
600 file => 'lib/Foo/Bar/Baz.pm',
601 version => '0.3',
602 },
603 }
604 (Spec 1.2) [optional] {Map}
606 This describes all packages provided by this distribution. This
608 information is used by distribution and automation mechanisms like
609 PAUSE, CPAN, metacpan.org and search.cpan.org to build indexes saying
610 in which distribution various packages can be found.
611 The keys of "provides" are package names that can be found within the
613 distribution. If a package name key is provided, it must have a Map
614 with the following valid subkeys:
615 file
617 This field is required. It must contain a Unix-style relative file
618 path from the root of the distribution directory to a file that
619 contains or generates the package. It may be given as "META.yml"
620 or "META.json" to claim a package for indexing without needing a
621 "*.pm".
622 version
624 If it exists, this field must contains a Version String for the
625 package. If the package does not have a $VERSION, this field must
626 be omitted.
627 resources
629 Example:
631 resources => {
633 license => [ 'http://dev.perl.org/licenses/' ],
634 homepage => 'http://sourceforge.net/projects/module-build',
635 bugtracker => {
636 web => 'http://rt.cpan.org/Public/Dist/Display.html?Name=CPAN-Meta',
637 mailto => 'meta-bugs@example.com',
638 },
639 repository => {
640 url => 'git://github.com/dagolden/cpan-meta.git',
641 web => 'http://github.com/dagolden/cpan-meta',
642 type => 'git',
643 },
644 x_twitter => 'http://twitter.com/cpan_linked/',
645 }
646 (Spec 2) [optional] {Map}
648 This field describes resources related to this distribution.
650 Valid subkeys include:
652 homepage
654 The official home of this project on the web.
655 license
657 A List of URL's that relate to this distribution's license. As
658 with the top-level "license" field, distribution documentation
659 should be consulted to clarify the interpretation of multiple
660 licenses provided here.
661 bugtracker
663 This entry describes the bug tracking system for this distribution.
664 It is a Map with the following valid keys:
665 web - a URL pointing to a web front-end for the bug tracker
667 mailto - an email address to which bugs can be sent
668 repository
670 This entry describes the source control repository for this
671 distribution. It is a Map with the following valid keys:
672 url - a URL pointing to the repository itself
674 web - a URL pointing to a web front-end for the repository
675 type - a lowercase string indicating the VCS used
676 Because a url like "http://myrepo.example.com/" is ambiguous as to
678 type, producers should provide a "type" whenever a "url" key is
679 given. The "type" field should be the name of the most common
680 program used to work with the repository, e.g. "git", "svn", "cvs",
681 "darcs", "bzr" or "hg".
682 DEPRECATED FIELDS
684 build_requires
685 (Deprecated in Spec 2) [optional] {String}
687 Replaced by "prereqs"
689 configure_requires
691 (Deprecated in Spec 2) [optional] {String}
693 Replaced by "prereqs"
695 conflicts
697 (Deprecated in Spec 2) [optional] {String}
699 Replaced by "prereqs"
701 distribution_type
703 (Deprecated in Spec 2) [optional] {String}
705 This field indicated 'module' or 'script' but was considered
707 meaningless, since many distributions are hybrids of several kinds of
708 things.
709 license_uri
711 (Deprecated in Spec 1.2) [optional] {URL}
713 Replaced by "license" in "resources"
715 private
717 (Deprecated in Spec 1.2) [optional] {Map}
719 This field has been renamed to "no_index".
721 recommends
723 (Deprecated in Spec 2) [optional] {String}
725 Replaced by "prereqs"
727 requires
729 (Deprecated in Spec 2) [optional] {String}
731 Replaced by "prereqs"
733
735 Version Formats
736 This section defines the Version type, used by several fields in the
737 CPAN Meta Spec.
738 Version numbers must be treated as strings, not numbers. For example,
740 1.200 must not be serialized as 1.2. Version comparison should be
741 delegated to the Perl version module, version 0.80 or newer.
742 Unless otherwise specified, version numbers must appear in one of two
744 formats:
745 Decimal versions
747 Decimal versions are regular "decimal numbers", with some
748 limitations. They must be non-negative and must begin and end with
749 a digit. A single underscore may be included, but must be between
750 two digits. They must not use exponential notation ("1.23e-2").
751 version => '1.234' # OK
753 version => '1.23_04' # OK
754 version => '1.23_04_05' # Illegal
756 version => '1.' # Illegal
757 version => '.1' # Illegal
758 Dotted-integer versions
760 Dotted-integer (also known as dotted-decimal) versions consist of
761 positive integers separated by full stop characters (i.e. "dots",
762 "periods" or "decimal points"). This are equivalent in format to
763 Perl "v-strings", with some additional restrictions on form. They
764 must be given in "normal" form, which has a leading "v" character
765 and at least three integer components. To retain a one-to-one
766 mapping with decimal versions, all components after the first
767 should be restricted to the range 0 to 999. The final component
768 may be separated by an underscore character instead of a period.
769 version => 'v1.2.3' # OK
771 version => 'v1.2_3' # OK
772 version => 'v1.2.3.4' # OK
773 version => 'v1.2.3_4' # OK
774 version => 'v2009.10.31' # OK
775 version => 'v1.2' # Illegal
777 version => '1.2.3' # Illegal
778 version => 'v1.2_3_4' # Illegal
779 version => 'v1.2009.10.31' # Not recommended
780 Version Ranges
782 Some fields (prereq, optional_features) indicate the particular
783 version(s) of some other module that may be required as a prerequisite.
784 This section details the Version Range type used to provide this
785 information.
786 The simplest format for a Version Range is just the version number
788 itself, e.g. 2.4. This means that at least version 2.4 must be
789 present. To indicate that any version of a prerequisite is okay, even
790 if the prerequisite doesn't define a version at all, use the version 0.
791 Alternatively, a version range may use the operators < (less than), <=
793 (less than or equal), > (greater than), >= (greater than or equal), ==
794 (equal), and != (not equal). For example, the specification "< 2.0"
795 means that any version of the prerequisite less than 2.0 is suitable.
796 For more complicated situations, version specifications may be AND-ed
798 together using commas. The specification >= 1.2, != 1.5, < 2.0
799 indicates a version that must be at least 1.2, less than 2.0, and not
800 equal to 1.5.
801
803 Prereq Spec
804 The "prereqs" key in the top-level metadata and within
805 "optional_features" define the relationship between a distribution and
806 other packages. The prereq spec structure is a hierarchical data
807 structure which divides prerequisites into Phases of activity in the
808 installation process and Relationships that indicate how prerequisites
809 should be resolved.
810 For example, to specify that "Data::Dumper" is "required" during the
812 "test" phase, this entry would appear in the distribution metadata:
813 prereqs => {
815 test => {
816 requires => {
817 'Data::Dumper' => '2.00'
818 }
819 }
820 }
821 Phases
823 Requirements for regular use must be listed in the "runtime" phase.
825 Other requirements should be listed in the earliest stage in which they
826 are required and consumers must accumulate and satisfy requirements
827 across phases before executing the activity. For example, "build"
828 requirements must also be available during the "test" phase.
829 before action requirements that must be met
831 ---------------- --------------------------------
832 perl Build.PL configure
833 perl Makefile.PL
834 make configure, runtime, build
836 Build
837 make test configure, runtime, build, test
839 Build test
840 Consumers that install the distribution must ensure that runtime
842 requirements are also installed and may install dependencies from other
843 phases.
844 after action requirements that must be met
846 ---------------- --------------------------------
847 make install runtime
848 Build install
849 configure
851 The configure phase occurs before any dynamic configuration has
852 been attempted. Libraries required by the configure phase must be
853 available for use before the distribution building tool has been
854 executed.
855 build
857 The build phase is when the distribution's source code is compiled
858 (if necessary) and otherwise made ready for installation.
859 test
861 The test phase is when the distribution's automated test suite is
862 run. Any library that is needed only for testing and not for
863 subsequent use should be listed here.
864 runtime
866 The runtime phase refers not only to when the distribution's
867 contents are installed, but also to its continued use. Any library
868 that is a prerequisite for regular use of this distribution should
869 be indicated here.
870 develop
872 The develop phase's prereqs are libraries needed to work on the
873 distribution's source code as its author does. These tools might
874 be needed to build a release tarball, to run author-only tests, or
875 to perform other tasks related to developing new versions of the
876 distribution.
877 Relationships
879 requires
881 These dependencies must be installed for proper completion of the
882 phase.
883 recommends
885 Recommended dependencies are strongly encouraged and should be
886 satisfied except in resource constrained environments.
887 suggests
889 These dependencies are optional, but are suggested for enhanced
890 operation of the described distribution.
891 conflicts
893 These libraries cannot be installed when the phase is in operation.
894 This is a very rare situation, and the "conflicts" relationship
895 should be used with great caution, or not at all.
896 Merging and Resolving Prerequisites
898 Whenever metadata consumers merge prerequisites, either from different
899 phases or from "optional_features", they should merged in a way which
900 preserves the intended semantics of the prerequisite structure.
901 Generally, this means concatenating the version specifications using
902 commas, as described in the "Version Ranges" section.
903 Another subtle error that can occur in resolving prerequisites comes
905 from the way that modules in prerequisites are indexed to distribution
906 files on CPAN. When a module is deleted from a distribution,
907 prerequisites calling for that module could indicate an older
908 distribution should be installed, potentially overwriting files from a
909 newer distribution.
910 For example, as of Oct 31, 2009, the CPAN index file contained these
912 module-distribution mappings:
913 Class::MOP 0.94 D/DR/DROLSKY/Class-MOP-0.94.tar.gz
915 Class::MOP::Class 0.94 D/DR/DROLSKY/Class-MOP-0.94.tar.gz
916 Class::MOP::Class::Immutable 0.04 S/ST/STEVAN/Class-MOP-0.36.tar.gz
917 Consider the case where "Class::MOP" 0.94 is installed. If a
919 distribution specified "Class::MOP::Class::Immutable" as a
920 prerequisite, it could result in Class-MOP-0.36.tar.gz being installed,
921 overwriting any files from Class-MOP-0.94.tar.gz.
922 Consumers of metadata should test whether prerequisites would result in
924 installed module files being "downgraded" to an older version and may
925 warn users or ignore the prerequisite that would cause such a result.
926
928 Distribution metadata should be serialized (as a hashref) as JSON-
929 encoded data and packaged with distributions as the file META.json.
930 In the past, the distribution metadata structure had been packed with
932 distributions as META.yml, a file in the YAML Tiny format (for which,
933 see YAML::Tiny). Tools that consume distribution metadata from disk
934 should be capable of loading META.yml, but should prefer META.json if
935 both are found.
936
938 Extracting Version Numbers from Perl Modules
939 To get the version number from a Perl module, consumers should use the
940 "MM->parse_version($file)" method provided by ExtUtils::MakeMaker or
941 Module::Metadata. For example, for the module given by $mod, the
942 version may be retrieved in one of the following ways:
943 # via ExtUtils::MakeMaker
945 my $file = MM->_installed_file_for_module($mod);
946 my $version = MM->parse_version($file)
947 The private "_installed_file_for_module" method may be replaced with
949 other methods for locating a module in @INC.
950 # via Module::Metadata
952 my $info = Module::Metadata->new_from_module($mod);
953 my $version = $info->version;
954 If only a filename is available, the following approach may be used:
956 # via Module::Build
958 my $info = Module::Metadata->new_from_file($file);
959 my $version = $info->version;
960 Comparing Version Numbers
962 The version module provides the most reliable way to compare version
963 numbers in all the various ways they might be provided or might exist
964 within modules. Given two strings containing version numbers, $v1 and
965 $v2, they should be converted to "version" objects before using
966 ordinary comparison operators. For example:
967 use version;
969 if ( version->new($v1) <=> version->new($v2) ) {
970 print "Versions are not equal\n";
971 }
972 If the only comparison needed is whether an installed module is of a
974 sufficiently high version, a direct test may be done using the string
975 form of "eval" and the "use" function. For example, for module $mod
976 and version prerequisite $prereq:
977 if ( eval "use $mod $prereq (); 1" ) {
979 print "Module $mod version is OK.\n";
980 }
981 If the values of $mod and $prereq have not been scrubbed, however, this
983 presents security implications.
984 Prerequisites for dynamically configured distributions
986 When "dynamic_config" is true, it is an error to presume that the
987 prerequisites given in distribution metadata will have any relationship
988 whatsoever to the actual prerequisites of the distribution.
989 In practice, however, one can generally expect such prerequisites to be
991 one of two things:
992 • The minimum prerequisites for the distribution, to which dynamic
994 configuration will only add items
995 • Whatever the distribution configured with on the releaser's machine
997 at release time
998 The second case often turns out to have identical results to the first
1000 case, albeit only by accident.
1001 As such, consumers may use this data for informational analysis, but
1003 presenting it to the user as canonical or relying on it as such is
1004 invariably the height of folly.
1005 Indexing distributions a la PAUSE
1007 While no_index tells you what must be ignored when indexing, this spec
1008 holds no opinion on how you should get your initial candidate list of
1009 things to possibly index. For "normal" distributions you might consider
1010 simply indexing the contents of lib/, but there are many fascinating
1011 oddities on CPAN and many dists from the days when it was normal to put
1012 the main .pm file in the root of the distribution archive - so PAUSE
1013 currently indexes all .pm and .PL files that are not either (a)
1014 specifically excluded by no_index (b) in "inc", "xt", or "t"
1015 directories, or common 'mistake' directories such as "perl5".
1016 Or: If you're trying to be PAUSE-like, make sure you skip "inc", "xt"
1018 and "t" as well as anything marked as no_index.
1019 Also remember: If the META file contains a provides field, you
1021 shouldn't be indexing anything in the first place - just use that.
1022
1024 • CPAN, <http://www.cpan.org/>
1025 • JSON, <http://json.org/>
1027 • YAML, <http://www.yaml.org/>
1029 • CPAN
1031 • CPANPLUS
1033 • ExtUtils::MakeMaker
1035 • Module::Build
1037 • Module::Install
1039 • CPAN::Meta::History::Meta_1_4
1041
1043 Ken Williams wrote the original CPAN Meta Spec (also known as the
1044 "META.yml spec") in 2003 and maintained it through several revisions
1045 with input from various members of the community. In 2005, Randy Sims
1046 redrafted it from HTML to POD for the version 1.2 release. Ken
1047 continued to maintain the spec through version 1.4.
1048 In late 2009, David Golden organized the version 2 proposal review
1050 process. David and Ricardo Signes drafted the final version 2 spec in
1051 April 2010 based on the version 1.4 spec and patches contributed during
1052 the proposal process.
1053
1055 • David Golden <dagolden@cpan.org>
1056 • Ricardo Signes <rjbs@cpan.org>
1058 • Adam Kennedy <adamk@cpan.org>
1060
1062 This software is copyright (c) 2010 by David Golden, Ricardo Signes,
1063 Adam Kennedy and Contributors.
1064 This is free software; you can redistribute it and/or modify it under
1066 the same terms as the Perl 5 programming language system itself.
1067perl v5.36.0 2023-01-20 CPAN::Meta::Spec(3)