PEP 426/440 update

pep-0426/pymeta-schema.json

@@ -0,0 +1,244 @@
+{
+  "id": "http://www.python.org/dev/peps/pep-0426/",
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "title": "Metadata for Python Software Packages 2.0",
+  "type": "object",
+  "properties": {
+    "metadata_version": {
+      "description": "Version of the file format",
+      "type": "string",
+      "pattern": "^(\d+(\.\d+)*)$"
+    },
+    "name": {
+      "description": "The name of the distribution.",
+      "type": "string",
+      "pattern": "^[0-9A-Za-z]([0-9A-Za-z_.-]*[0-9A-Za-z])?$"
+    },
+    "version": {
+      "description": "The distribution's public version identifier",
+      "type": "string",
+      "pattern": "^(\d+(\.\d+)*)((a|b|c|rc)(\d+))?(\.(post)(\d+))?(\.(dev)(\d+))?$"
+    },
+    "source_label": {
+      "description": "A constrained identifying text string",
+      "type": "string",
+      "pattern": "^[0-9a-z_.-+]+$"
+    },
+    "source_url": {
+      "description": "A string containing a full URL where the source for this specific version of the distribution can be downloaded.",
+      "type": "string",
+      "format": "uri"
+    },
+    "summary": {
+      "description": "A one-line summary of what the distribution does.",
+      "type": "string"
+    },
+    "document_names": {
+      "description": "Names of supporting metadata documents",
+      "type": "object",
+      "properties": {
+        "description": {
+          "type": "string",
+          "$ref": "#/definitions/document_name"
+        },
+        "changelog": {
+          "type": "string",
+          "$ref": "#/definitions/document_name"
+        },
+        "license": {
+          "type": "string",
+          "$ref": "#/definitions/document_name"
+        }
+      },
+      "additionalProperties": false
+    },
+    "keywords": {
+      "description": "A list of additional keywords to be used to assist searching for the distribution in a larger catalog.",
+      "type": "array",
+      "items": {
+        "type": "string"
+      }
+    },
+    "license": {
+      "description": "A string indicating the license covering the distribution.",
+      "type": "string"
+    },
+    "classifiers": {
+      "description": "A list of strings, with each giving a single classification value for the distribution.",
+      "type": "array",
+      "items": {
+        "type": "string"
+      }
+    },
+    "contacts": {
+      "description": "A list of contributor entries giving the recommended contact points for getting more information about the project.",
+      "type": "array",
+      "items": {
+        "type": "object",
+        "$ref": "#/definitions/contact"
+      }
+    },
+    "contributors": {
+      "description": "A list of contributor entries for other contributors not already listed as current project points of contact.",
+      "type": "array",
+      "items": {
+        "type": "object",
+        "$ref": "#/definitions/contact"
+      }
+    },
+    "project_urls": {
+      "description": "A mapping of arbitrary text labels to additional URLs relevant to the project.",
+      "type": "object"
+    },
+    "extras": {
+      "description": "A list of optional sets of dependencies that may be used to define conditional dependencies in \"may_require\" and similar fields.",
+      "type": "array",
+      "items": {
+        "type": "string",
+        "$ref": "#/definitions/extra_name"
+      }
+    },
+    "distributes": {
+      "description": "A list of subdistributions made available through this metadistribution.",
+      "type": "array",
+      "$ref": "#/definitions/dependencies"
+    },
+    "may_distribute": {
+      "description": "A list of subdistributions that may be made available through this metadistribution, based on the extras requested and the target deployment environment.",
+      "$ref": "#/definitions/conditional_dependencies"
+    },
+    "run_requires": {
+      "description": "A list of other distributions needed when to run this distribution.",
+      "type": "array",
+      "$ref": "#/definitions/dependencies"
+    },
+    "run_may_require": {
+      "description": "A list of other distributions that may be needed when this distribution is deployed, based on the extras requested and the target deployment environment.",
+      "$ref": "#/definitions/conditional_dependencies"
+    },
+    "test_requires": {
+      "description": "A list of other distributions needed when this distribution is tested.",
+      "type": "array",
+      "$ref": "#/definitions/dependencies"
+    },
+    "test_may_require": {
+      "description": "A list of other distributions that may be needed when this distribution is tested, based on the extras requested and the target deployment environment.",
+      "type": "array",
+      "$ref": "#/definitions/conditional_dependencies"
+    },
+    "build_requires": {
+      "description": "A list of other distributions needed when this distribution is built.",
+      "type": "array",
+      "$ref": "#/definitions/dependencies"
+    },
+    "build_may_require": {
+      "description": "A list of other distributions that may be needed when this distribution is built, based on the extras requested and the target deployment environment.",
+      "type": "array",
+      "$ref": "#/definitions/conditional_dependencies"
+    },
+    "dev_requires": {
+      "description": "A list of other distributions needed when this distribution is developed.",
+      "type": "array",
+      "$ref": "#/definitions/dependencies"
+    },
+    "dev_may_require": {
+      "description": "A list of other distributions that may be needed when this distribution is developed, based on the extras requested and the target deployment environment.",
+      "type": "array",
+      "$ref": "#/definitions/conditional_dependencies"
+    },
+    "provides": {
+      "description": "A list of strings naming additional dependency requirements that are satisfied by installing this distribution. These strings must be of the form Name or Name (Version), as for the requires field.",
+      "type": "array",
+      "items": {
+        "type": "string"
+      }
+    },
+    "obsoleted_by": {
+      "description": "A string that indicates that this project is no longer being developed. The named project provides a substitute or replacement.",
+      "type": "string",
+      "$ref": "#/definitions/version_specifier"
+    },
+    "supports_environments": {
+      "description": "A list of strings specifying the environments that the distribution explicitly supports.",
+      "type": "array",
+      "items": {
+        "type": "string",
+        "$ref": "#/definitions/environment_marker"
+      }
+    },
+    "metabuild_hooks": {
+      "description": "The metabuild_hooks field is used to define various operations that may be invoked on a distribution in a platform independent manner.",
+      "type": "object"
+    },
+    "extensions": {
+      "description": "Extensions to the metadata may be present in a mapping under the 'extensions' key.",
+      "type": "object"
+    }
+  },
+
+  "required": ["metadata_version", "name", "version"],
+  "additionalProperties": false,
+
+  "definitions": {
+    "contact": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "type": "string"
+        },
+        "email": {
+          "type": "string"
+        },
+        "url": {
+          "type": "string"
+        },
+        "role": {
+          "type": "string"
+        }
+      },
+      "required": ["name"],
+      "additionalProperties": false
+    },
+    "dependencies": {
+      "type": "array",
+      "items": {
+        "type": "string",
+        "$ref": "#/definitions/version_specifier"
+      }
+    },
+    "conditional_dependencies": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "properties": {
+          "extra": {
+            "type": "string",
+            "$ref": "#/definitions/extra_name"
+          },
+          "environment": {
+            "type": "string",
+            "$ref": "#/definitions/environment_marker"
+          },
+          "dependencies": {
+            "type": "array",
+            "$ref": "#/definitions/dependencies"
+          }
+        },
+        "required": ["dependencies"],
+        "additionalProperties": false
+      }
+    },
+    "version_specifier": {
+        "type": "string"
+    },
+    "extra_name": {
+        "type": "string"
+    },
+    "environment_marker": {
+        "type": "string"
+    },
+    "document_name": {
+        "type": "string"
+    }
+  }
+}

pep-0440.txt

@@ -27,7 +27,7 @@ standardised approach to versioning, as described in PEP 345 and PEP 386.
    This PEP was broken out of the metadata 2.0 specification in PEP 426.
 
    Unlike PEP 426, the notes that remain in this document are intended as
-   part of the final specification.
+   part of the final specification (except for this one).
 
 
 Definitions
@@ -40,7 +40,7 @@ document are to be interpreted as described in RFC 2119.
 The following terms are to be interpreted as described in PEP 426:
 
 * "Distributions"
-* "Versions"
+* "Releases"
 * "Build tools"
 * "Index servers"
 * "Publication tools"
@@ -52,9 +52,13 @@ The following terms are to be interpreted as described in PEP 426:
 Version scheme
 ==============
 
-Distribution versions are identified by both a public version identifier,
+Distributions are identified by a public version identifier which
-which supports all defined version comparison operations, and a build
+supports all defined version comparison operations
-label, which supports only strict equality comparisons.
+
+Distributions may also define a source label, which is not used by
+automated tools. Source labels are useful when a project internal
+versioning scheme requires translation to create a compliant public
+version identifier.
 
 The version scheme is used both to describe the distribution version
 provided by a particular distribution archive, as well as to place
@@ -84,7 +88,7 @@ Public version identifiers are separated into up to four segments:
 * Post-release segment: ``.postN``
 * Development release segment: ``.devN``
 
-Any given version will be a "release", "pre-release", "post-release" or
+Any given release will be a "final release", "pre-release", "post-release" or
 "developmental release" as defined in the following sections.
 
 .. note::
@@ -105,28 +109,37 @@ Source labels
 Source labels are text strings with minimal defined semantics.
 
 To ensure source labels can be readily incorporated as part of file names
-and URLs, they MUST be comprised of only ASCII alphanumerics, plus signs,
+and URLs, and to avoid formatting inconsistences in hexadecimal hash
-periods and hyphens.
+representations they MUST be limited to the following set of permitted
+characters:
 
-In addition, source labels MUST be unique within a given distribution.
+* Lowercase ASCII letters (``[a-z]``)
+* ASCII digits (``[0-9]``)
+* underscores (``_``)
+* hyphens (``-``)
+* periods (``.``)
+* plus signs (``+``)
 
-As with distribution names, all comparisons of source labels MUST be case
+Source labels MUST start and end with an ASCII letter or digit.
-insensitive.
+
+Source labels MUST be unique within each project and MUST NOT match any
+defined version for the project.
 
 
-Releases
+Final releases
---------
+--------------
 
-A version identifier that consists solely of a release segment is termed
+A version identifier that consists solely of a release segment is
-a "release".
+termed a "final release".
 
-The release segment consists of one or more non-negative integer values,
+The release segment consists of one or more non-negative integer
-separated by dots::
+values, separated by dots::
 
     N[.N]+
 
-Releases within a project will typically be numbered in a consistently
+Final releases within a project MUST be numbered in a consistently
-increasing fashion.
+increasing fashion, otherwise automated tools will not be able to upgrade
+them correctly.
 
 Comparison and ordering of release segments considers the numeric value
 of each component of the release segment in turn. When comparing release
@@ -157,8 +170,8 @@ For example::
     2.0
     2.0.1
 
-A release series is any set of release numbers that start with a common
+A release series is any set of final release numbers that start with a
-prefix. For example, ``3.3.1``, ``3.3.5`` and ``3.3.9.45`` are all
+common prefix. For example, ``3.3.1``, ``3.3.5`` and ``3.3.9.45`` are all
 part of the ``3.3`` release series.
 
 .. note::
@@ -206,8 +219,8 @@ of both ``c`` and ``rc`` releases for a common release segment.
 Post-releases
 -------------
 
-Some projects use post-releases to address minor errors in a release that
+Some projects use post-releases to address minor errors in a final release
-do not affect the distributed software (for example, correcting an error
+that do not affect the distributed software (for example, correcting an error
 in the release notes).
 
 If used as part of a project's development cycle, these post-releases are
@@ -371,7 +384,7 @@ are permitted and MUST be ordered as shown::
    .devN, aN, bN, cN, rcN, <no suffix>, .postN
 
 Note that `rc` will always sort after `c` (regardless of the numeric
-component) although they are semantically equivalent. Tools are free to
+component) although they are semantically equivalent. Tools MAY
 reject this case as ambiguous and remain in compliance with the PEP.
 
 Within an alpha (``1.0a1``), beta (``1.0b1``), or release candidate
@@ -506,6 +519,22 @@ numbering based on API compatibility, as well as triggering more appropriate
 version comparison semantics.
 
 
+Olson database versioning
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The ``pytz`` project inherits its versioning scheme from the corresponding
+Olson timezone database versioning scheme: the year followed by a lowercase
+character indicating the version of the database within that year.
+
+This can be translated to a compliant 3-part version identifier as
+``0.<year>.<serial>``, where the serial starts at zero (for the '<year>a'
+release) and is incremented with each subsequent database update within the
+year.
+
+As with other translated version identifiers, the corresponding Olson
+database version would be recorded in the source label field.
+
+
 Version specifiers
 ==================
 
@@ -521,7 +550,7 @@ clause:
 * ``~=``: `Compatible release`_ clause
 * ``==``: `Version matching`_ clause
 * ``!=``: `Version exclusion`_ clause
-* ``is``: `Source reference`_ clause
+* ``is``: `Direct reference`_ clause
 * ``<=``, ``>=``: `Inclusive ordered comparison`_ clause
 * ``<``, ``>``: `Exclusive ordered comparison`_ clause
 
@@ -605,6 +634,11 @@ version. The *only* substitution performed is the zero padding of the
 release segment to ensure the release segments are compared with the same
 length.
 
+Whether or not strict version matching is appropriate depends on the specific
+use case for the version specifier. Automated tools SHOULD at least issue
+warnings and MAY reject them entirely when strict version matches are used
+inappropriately.
+
 Prefix matching may be requested instead of strict comparison, by appending
 a trailing ``.*`` to the version identifier in the version matching clause.
 This means that additional trailing segments will be ignored when
@@ -645,49 +679,42 @@ match or not as shown::
     != 1.1.*      # Same prefix, so 1.1.post1 does not match clause
 
 
-Source reference
+Direct reference
 ----------------
 
-A source reference includes the source reference operator ``is`` and
+A direct reference includes the direct reference operator ``is`` and
-a source label or a source URL.
+an explicit URL.
 
-Installation tools MAY also permit direct references to a platform
+Whether or not direct references are appropriate depends on the specific
-appropriate binary archive in a source reference clause.
+use case for the version specifier. Automated tools SHOULD at least issue
+warnings and MAY reject them entirely when direct references are used
+inappropriately.
 
-Publication tools and public index servers SHOULD NOT permit direct
+Depending on the use case, some appropriate targets for a direct URL
-references to a platform appropriate binary archive in a source
+reference are a source archive, an sdist, a wheel binary archive or a
-reference clause.
+direct reference to a tag or specific commit in an online version control
-
+system. The exact URLs and targets supported will be automated tool
-Source label matching works solely on strict equality comparisons: the
+specific.
-candidate source label must be exactly the same as the source label in the
-version clause for the clause to match the candidate distribution.
-
-For example, a source reference could be used to depend directly on a
-version control hash based identifier rather than the translated public
-version::
-
-    exact-dependency (is 1.3.7+build.11.e0f985a)
-
-A source URL is distinguished from a source label by the presence of
-``:`` and ``/`` characters in the source reference. As these characters
-are not permitted in source labels, they indicate that the reference uses
-a source URL.
-
-Some appropriate targets for a source URL are a source tarball, an sdist
-archive or a direct reference to a tag or specific commit in an online
-version control system. The exact URLs and
-targets supported will be installation tool specific.
 
 For example, a local source archive may be referenced directly::
 
     pip (is file:///localbuilds/pip-1.3.1.zip)
 
-All source URL references SHOULD either specify a local file URL, a secure
+Alternatively, a prebuilt archive may also be referenced::
-transport mechanism (such as ``https``) or else include an expected hash
+
-value in the URL for verification purposes. If an insecure network
+    pip (is file:///localbuilds/pip-1.3.1-py33-none-any.whl)
-transport is specified without any hash information (or with hash
+
-information that the tool doesn't understand), automated tools SHOULD
+
-at least emit a warning and MAY refuse to rely on the URL.
+All direct URL references that do not refer to a local file URL SHOULD
+specify a secure transport mechanism (such as ``https``), include an
+expected hash value in the URL for verification purposes, or both. If an
+insecure transport is specified without any hash information, with hash
+information that the tool doesn't understand, or with a selected hash
+algortihm that the tool considers too weak to trust, automated tools
+SHOULD at least emit a warning and MAY refuse to rely on the URL.
+
+Index servers MAY place additional restrictions on direct references (such
+as requiring all references be to files hosted on the index server itself).
 
 It is RECOMMENDED that only hashes which are unconditionally provided by
 the latest version of the standard library's ``hashlib`` module be used
@@ -695,24 +722,17 @@ for source archive hashes. At time of writing, that list consists of
 ``'md5'``, ``'sha1'``, ``'sha224'``, ``'sha256'``, ``'sha384'``, and
 ``'sha512'``.
 
-For source archive references, an expected hash value may be
+For source archive and wheel references, an expected hash value may be
 specified by including a ``<hash-algorithm>=<expected-hash>`` as part of
 the URL fragment.
 
-For version control references, the ``VCS+protocol`` scheme SHOULD be
+Version control references, the ``VCS+protocol`` scheme SHOULD be
 used to identify both the version control system and the secure transport.
 
 To support version control systems that do not support including commit or
 tag references directly in the URL, that information may be appended to the
 end of the URL using the ``@<tag>`` notation.
 
-The use of ``is`` when defining dependencies for published distributions
-is strongly discouraged as it greatly complicates the deployment of
-security fixes. The source label matching operator is intended primarily
-for use when defining dependencies for repeatable *deployments of
-applications* while using a shared distribution index, as well as to
-reference dependencies which are not published through an index server.
-
 
 Inclusive ordered comparison
 ----------------------------
@@ -752,62 +772,47 @@ Handling of pre-releases
 ------------------------
 
 Pre-releases of any kind, including developmental releases, are implicitly
-excluded from all version specifiers, *unless* a pre-release or developmental
+excluded from all version specifiers, *unless* they are already present
-release is explicitly mentioned in one of the clauses. For example, these
+on the system, explicitly requested by the user, or if the only available
-specifiers implicitly exclude all pre-releases and development
+version that satisfies the version specifier is a pre-release.
-releases of later versions::
-
-    2.2
-    >= 1.0
-
-While these specifiers would include at least some of them::
-
-    2.2.dev0
-    2.2, != 2.3b2
-    >= 1.0a1
-    >= 1.0c1
-    >= 1.0, != 1.0b2
-    >= 1.0, < 2.0.dev123
 
 By default, dependency resolution tools SHOULD:
 
 * accept already installed pre-releases for all version specifiers
-* accept remotely available pre-releases for version specifiers which
+* accept remotely available pre-releases for version specifiers where
-  include at least one version clauses that references a pre-release
+  there is no final or post release that satisfies the version specifier
 * exclude all other pre-releases from consideration
 
+Dependency resolution tools MAY issue a warning if a pre-release is needed
+to satisfy a version specifier.
+
 Dependency resolution tools SHOULD also allow users to request the
 following alternative behaviours:
 
 * accepting pre-releases for all version specifiers
 * excluding pre-releases for all version specifiers (reporting an error or
-  warning if a pre-release is already installed locally)
+  warning if a pre-release is already installed locally, or if a
+  pre-release is the only way to satisfy a particular specifier)
 
 Dependency resolution tools MAY also allow the above behaviour to be
 controlled on a per-distribution basis.
 
-Post-releases and purely numeric releases receive no special treatment in
+Post-releases and final releases receive no special treatment in version
-version specifiers - they are always included unless explicitly excluded.
+specifiers - they are always included unless explicitly excluded.
 
 
 Examples
 --------
 
-* ``3.1``: version 3.1 or later, but not
+* ``3.1``: version 3.1 or later, but not version 4.0 or later.
-   version 4.0 or later. Excludes pre-releases and developmental releases.
+* ``3.1.2``: version 3.1.2 or later, but not version 3.2.0 or later.
-* ``3.1.2``: version 3.1.2 or later, but not
+* ``3.1a1``: version 3.1a1 or later, but not version 4.0 or later.
-   version 3.2.0 or later. Excludes pre-releases and developmental releases.
-* ``3.1a1``: version 3.1a1 or later, but not
-   version 4.0 or later. Allows pre-releases like 3.2a4 and developmental
-   releases like 3.2.dev1.
 * ``== 3.1``: specifically version 3.1 (or 3.1.0), excludes all pre-releases,
   post releases, developmental releases and any 3.1.x maintenance releases.
-* ``== 3.1.*``: any version that starts with 3.1, excluding pre-releases and
+* ``== 3.1.*``: any version that starts with 3.1. Equivalent to the
-  developmental releases. Equivalent to the ``3.1.0`` compatible release
+  ``3.1.0`` compatible release clause.
-  clause.
 * ``3.1.0, != 3.1.3``: version 3.1.0 or later, but not version 3.1.3 and
-  not version 3.2.0 or later. Excludes pre-releases and developmental
+  not version 3.2.0 or later.
-  releases.
 
 
 Updating the versioning specification
@@ -825,28 +830,29 @@ Summary of differences from \PEP 386
 
 * Moved the description of version specifiers into the versioning PEP
 
-* added the "source label" concept to better handle projects that wish to
+* Aadded the "source label" concept to better handle projects that wish to
   use a non-compliant versioning scheme internally, especially those based
   on DVCS hashes
   
-* added the "compatible release" clause
+* Added the "compatible release" clause
 
-* added the "source reference" clause
+* Added the "direct reference" clause
 
-* added the trailing wildcard syntax for prefix based version matching
+* Added the trailing wildcard syntax for prefix based version matching
   and exclusion
 
-* changed the top level sort position of the ``.devN`` suffix
+* Changed the top level sort position of the ``.devN`` suffix
 
-* allowed single value version numbers
+* Allowed single value version numbers
 
-* explicit exclusion of leading or trailing whitespace
+* Explicit exclusion of leading or trailing whitespace
 
-* explicit criterion for the exclusion of date based versions
+* Explicit criterion for the exclusion of date based versions
 
-* implicitly exclude pre-releases unless explicitly requested
+* Implicitly exclude pre-releases unless they're already present or
+  needed to satisfy a dependency
 
-* treat post releases the same way as unqualified releases
+* Treat post releases the same way as unqualified releases
 
 * Discuss ordering and dependencies across metadata versions
 
@@ -995,11 +1001,12 @@ The previous interpretation also excluded post-releases from some version
 specifiers for no adequately justified reason.
 
 The updated interpretation is intended to make it difficult to accidentally
-accept a pre-release version as satisfying a dependency, while allowing
+accept a pre-release version as satisfying a dependency, while still
-pre-release versions to be explicitly requested when needed.
+allowing pre-release versions to be retrieved automatically when that's the
+only way to satisfy a dependency.
 
 The "some forward compatibility assumed" default version constraint is
-taken directly from the Ruby community's "pessimistic version constraint"
+derived from the Ruby community's "pessimistic version constraint"
 operator [2]_ to allow projects to take a cautious approach to forward
 compatibility promises, while still easily setting a minimum required
 version for their dependencies. It is made the default behaviour rather
@@ -1022,16 +1029,17 @@ improved tools for dynamic path manipulation.
 
 The trailing wildcard syntax to request prefix based version matching was
 added to make it possible to sensibly define both compatible release clauses
-and the desired pre-release handling semantics for ``<`` and ``>`` ordered
+and the desired pre- and post-release handling semantics for ``<`` and ``>``
-comparison clauses.
+ordered comparison clauses.
 
-Source references are added for two purposes. In conjunction with source
+Direct references are added as an "escape clause" to handle messy real
-labels, they allow hash based references to exact versions that aren't
+world situations that don't map neatly to the standard distribution model.
-compliant with the fully ordered public version scheme, such as those
+This includes dependencies on unpublished software for internal use, as well
-generated from version control. In combination with source URLs, they
+as handling the more complex compatibility issues that may arise when
-also allow the new metadata standard to natively support an existing
+wrapping third party libraries as C extensions (this is of especial concern
-feature of ``pip``, which allows arbitrary URLs like
+to the scientific community). Index servers are given a lot of freedom to
-``file:///localbuilds/exampledist-1.0-py33-none-any.whl``.
+disallow them, since they're intended primarily as a tool for integrators
+rather than publishers.
 
 
 References