Adopt "vers" version range spec

AUTHORS.rst

@@ -1,6 +1,6 @@
 The following organizations or individuals have contributed to this repo:
 
-- Shivam Sandbhor
-- nexB Inc.
-- Philippe Ombredanne
+- Shivam Sandbhor @sbs2001
+- Philippe Ombredanne @pombredanne
+- Hritik Vijay @Hritik14
 

README.rst

@@ -5,70 +5,116 @@ univers: mostly universal version and version ranges comparison and conversion
 
 .. |Build Status| image:: https://api.travis-ci.com/sbs2001/univers.svg?branch=main&status=passed
 .. |License| image:: https://img.shields.io/badge/License-Apache%202.0-blue.svg
-   :target: https://opensource.org/licenses/Apache-2.0
+   :target: https://scancode-licensedb.aboutcode.org/apache-2.0.html
 .. |Python 3.6+| image:: https://img.shields.io/badge/python-3.6+-blue.svg
    :target: https://www.python.org/downloads/release/python-380/
 
 
-
-univers was born out of the need for a mostly univeral way to perform software
-package version comparisons in VulnerableCode.
+**univers** was born out of the need for a mostly univeral way to store version
+ranges and to compare two software package versions in VulnerableCode.
 
 Package version ranges and version constraints are useful and essential:
 
+- When relating a known vulnerability or bug to a range of affected package
+  versions. For instance a statement such as "vulnerability 123 affects 
+  package bar, version 3.1 and version 4.2 but not version 5" defines a
+  range of bar versions affected by a vulnerability.
+
 - When resolving the dependencies of a package to express which subset of the
   versions are supported. For instance a dependency requirement statement such
   as "I require package foo, version 2.0 and later versions" defines a range of
   acceptable foo versions.
 
-- When relating a known vulnerability or bug to a range of affected package
-  versions. For instance a statement such as "vulnerability 123 affects 
-  package bar, version 3.1 and version 4.2 but not version 5" also defines a
-  range of affected bar versions.
+Version syntaxes and range notations are quite different across ecosystems,
+making it is difficult to process versions and version ranges across ecosystems
+in a consistent way.
 
-Existing tools support typically a single algorithm to parse and compare
-versions and this is not accurate across different ecosystems, since each
-follow different versioning rules. For example there's no concept of 'epoch' in
-semver versioning as used in package types and ecosystem such as npm or
-rubygems, but epochs do exist in debian versions. A tool designed for semver or
-dpkg versions processing would not be able to handle correctly the other version
-scheme.
+Existing tools and libraries typically support a single algorithms to parse and
+compare versions with a single version range notation for a single package
+ecosystem.
 
-univers is different and considers the ecosystem-specific version scheme used.
 
+**univers** is different:
 
-How does univers work ?
-=========================
+- It tracks each ecosystem versionning scheme and how two versions are compared.
 
-univers wraps, embeds or implements multiple version comparision libraries, each
-focused on specific ecosystem version scheme.
+- It support a growing number of package ecosystems versioning in a single
+  library.
 
-It also implements an experimental unified syntax for version ranges specifier
-and can parse and convert existing version range strings to this unified syntax.
+- It can parse version range strings using their native notation (such as an npm
+  range) into the common "vers" notation and internal object model and can
+  return back a native version range string rebuilt from a "vers" range.
 
+- It is designed to work with `Package URLs (purl) <https://github.com/package-url>`_.
 
-The supported package ecosystems versioning schemes and underlying libraries are:
 
-- semver: npm, golang, PHP composer, rubygems and others that follow the semver
-  spec, using `semantic_version <https://github.com/rbarrois/python-semanticversion>`_ library.
-- debian: handled by the 
-  `debian-inspector <https://github.com/sbs2001/univers/blob/main/src/univers/debian.py.ABOUT>`_
-  library.
+How does **univers** work ?
+============================
+
+**univers** wraps, embeds and implements multiple version comparison libraries,
+each focused on a specific ecosystem versionning scheme.
+
+For each scheme, **univers** provides an implementation for:
+
+- the version comparison procedure e.g, how to compare two versions,
+- parsing and converting from a native version range notation to the
+  **univers** normalized and unified internal model,
+- converting a range back to its scheme-native range syntax and to the
+  ``vers`` syntax.
+
+**univers** implements ``vers``, an experimental unified and mostly universal
+version range syntax. It can parse and convert an existing native version range
+strings to this unified syntax. For example, this means:
+
+- converting ">1.2.3" as used in a Python package into ``vers:pypi/>1.2.3``,
+
+- or converting "^1.0.2" as used in an npm package dependency declartion into
+  ``vers:npm/>=1.0.2,<2.0.0``
+
+The supported package ecosystems versioning schemes and underlying libraries
+include:
+
+- npm that use the "node-semver" ranges notation and the semver versions syntax
+  This is supported in part by the `semantic_version <https://github.com/rbarrois/python-semanticversion>`_ library.
+
 - pypi: handled by Python's packaging library and the standard ``packaging.version`` module.
-- maven: handled by the embedded `rpm_vercmp <https://github.com/sbs2001/univers/blob/main/src/univers/rpm.py.ABOUT>`_ library.
-- ebuild/gentoo: handled by the embedded `gentoo_vercmp <https://github.com/sbs2001/univers/blob/main/src/univers/gentoo.py.ABOUT>`_ module.
 
-As we grow, new schemes will be implemented accordingly.
+- Rubygems which use a semver-like but not-quite-semver scheme and there can be
+  commonly more than three version segments.
+  Gems also use a slightly different range notation from node-semver with
+  different operators and slightly different semantics: for instance it uses "~>"
+  as a pessimistic operator and supports exclusion with != and does not support
+  "OR" between constraints (that it call requirements).
+
+- debian: handled by the  `debian-inspector <https://github.com/nexB/univers/blob/main/src/univers/debian.py.ABOUT>`_
+  library.
+
+- maven: handled by the embedded `pymaven <https://github.com/nexB/univers/blob/main/src/univers/pymaven.py.ABOUT>`_ library.
+
+- rpm: handled by the embedded `rpm_vercmp <https://github.com/nexB/univers/blob/main/src/univers/rpm.py.ABOUT>`_ library.
+
+- golang (using semver)
+
+- PHP composer
+
+- ebuild/gentoo: handled by the embedded `gentoo_vercmp <https://github.com/nexB/univers/blob/main/src/univers/gentoo.py.ABOUT>`_ module.
+
+- arch linux : handled by the embedded `arch utility borrowed from msys2 <https://github.com/nexB/univers/blob/main/src/univers/arch.py.ABOUT>`_ module.
+
+The level of support for each ecosystem may not be even for now and new schemes
+and support for more package types are implemented on a continuous basis.
 
 
 Alternative
 ============
 
 Rather than using ecosystem-specific version schemes and code, another approach
 is to use a single procedure for all the versions as implemented in `libversion
-<https://github.com/repology/libversion>`_. This works in the most common case
-but may not work correctly for specific tasks that demand accurate version
-comparison such as for dependency resolution and vulnerabilities checks.
+<https://github.com/repology/libversion>`_. ``libversion`` works in the most
+common case but may not work correctly when a task that demand precise version
+comparisons such as for dependency resolution and vulnerability lookup where
+a "good enough" comparison accuracy is not acceptable. ``libversion`` does not
+handle version range notations.
 
 
 Installation
@@ -80,35 +126,40 @@ Installation
 Examples
 ========
 
-Compare two versions using the Python comparison operators:
+Compare two native Python versions:
+
+.. code:: python
+
+    from univers.version import PypiVersion
+    assert PypiVersion("1.2.3") < PypiVersion("1.2.4")
+
+
+Normalize a version range from an npm:
 
 .. code:: python
 
-    from univers.version import PYPIVersion
-    v1 = PYPIVersion("1.2.3")
-    v2 = PYPIVersion("1.2.4")
-    assert v1 < v2 == True
+    from univers.version_range import NpmVersionRange
+    range = NpmVersionRange.from_native("^1.0.2")
+    assert str(range) == "vers:npm/>=1.0.2,<2.0.0"
 
 
-Test if a version is within or outside of a version range:
+Test if a version is within or outside a version range:
 
 .. code:: python
 
-    from univers.version import PYPIVersion
-    from univers.version_specifier import VersionSpecifier
+    from univers.version import PypiVersion
+    from univers.version_range import VersionRange
 
-    vs = VersionSpecifier.from_scheme_version_spec_string("pypi", ">=1.2.4")
-    v1 = PYPIVersion("1.2.4")
-    v2 = PYPIVersion("1.2.3")
+    range = VersionRange.from_string("vers:pypi/>=1.2.4")
 
-    assert (v1 in vs ) == True
-    assert (v2 in vs ) == False
+    assert PypiVersion("1.2.4") in range
+    assert PypiVersion("1.2.3") not in range
 
 
 Development
 ============
 
-Starting from a git clone of https://github.com/nexB/univers run these::
+Run these commands, starting from a git clone of https://github.com/nexB/univers ::
 
     $ configure --dev
     $ source venv/bin/active
@@ -121,5 +172,6 @@ Visit https://github.com/nexB/univers and
 https://gitter.im/aboutcode-org/vulnerablecode and
 https://gitter.im/aboutcode-org/aboutcode for support and chat.
 
+
 Primary license: Apache-2.0
 SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause AND MIT

conftest.py

@@ -2,18 +2,6 @@
 # Copyright (c) nexB Inc. and others.
 # SPDX-License-Identifier: Apache-2.0
 #
-# Visit https://aboutcode.org and https://github.com/nexB/ for support and download.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# Visit https://aboutcode.org and https://github.com/nexB/univers for support and download.
 
 collect_ignore = ["setup.py"]

src/univers/arch.py

@@ -1,7 +1,10 @@
 #
-# Copyright 2016-2020 Christoph Reiter
+# Copyright (c) Christoph Reiter
 # SPDX-License-Identifier: MIT
-# Version comparision utility extracted from msys2 and further stripped down.
+# Version utility extracted from msys2 https://github.com/msys2/msys2-web/
+# and further stripped down.
+#
+# Visit https://aboutcode.org and https://github.com/nexB/univers for support and download.
 
 import re
 from itertools import zip_longest

src/univers/arch.py.ABOUT

@@ -7,6 +7,6 @@ license_expression: MIT
 homepage_url: https://github.com/msys2/msys2-web/
 
 notes: |
-    The version comparision utility is extracted from msys2 and further stripped down.
+    The version comparison utility is extracted from msys2 and further stripped down.
 
 notice_file: arch.py.NOTICE

src/univers/debian.py

@@ -1,10 +1,12 @@
 #
 # Copyright (c) nexB Inc. and others.
-# Exatrcted from http://nexb.com and https://github.com/nexB/debian_inspector/
+# Extracted from http://nexb.com and https://github.com/nexB/debian_inspector/
 # Copyright (c) Peter Odding
 # Author: Peter Odding <peter@peterodding.com>
 # URL: https://github.com/xolox/python-deb-pkg-tools
 # SPDX-License-Identifier: MIT
+#
+# Visit https://aboutcode.org and https://github.com/nexB/univers for support and download.
 
 import logging
 import operator as operator_module

src/univers/gentoo.py

@@ -1,12 +1,18 @@
 #
 # Copyright (c) 2006-2019, pkgcore contributors
 # SPDX-License-Identifier: BSD-3-Clause
-# Version comparision utility extracted from pkgcore and further stripped down.
+# Version comparison utility extracted from pkgcore and further stripped down.
+#
+# Visit https://aboutcode.org and https://github.com/nexB/univers for support and download.
 
 import re
 
 from univers.utils import cmp
+from univers.utils import remove_spaces
 
+_is_gentoo_version = re.compile(
+    r"^(?:\d+)(?:\.\d+)*[a-zA-Z]?(?:_(p(?:re)?|beta|alpha|rc)\d*)*$"
+).match
 
 suffix_regexp = re.compile("^(alpha|beta|rc|pre|p)(\\d*)$")
 
@@ -19,6 +25,11 @@
 """
 
 
+def is_valid(string):
+    version, _ = parse_version_and_revision(remove_spaces(string))
+    return _is_gentoo_version(version)
+
+
 def parse_version_and_revision(version_string):
     """
     Return a tuple of (version string, revision int) given a ``version_string``.

src/univers/gentoo.py.ABOUT

@@ -6,6 +6,6 @@ copyright: |
 license_expression: BSD-3-Clause
 homepage_url: https://github.com/pkgcore/pkgcore/blob/master/src/pkgcore/ebuild/cpv.py
 
-notes: The version comparision utility is extracted from pkgcore and further stripped down.
+notes: The version comparison utility is extracted from pkgcore and further stripped down.
 
 notice_file: gentoo.py.NOTICE

src/univers/maven.py

@@ -1,8 +1,10 @@
 #
 # Copyright (c) SAS Institute Inc.
 # SPDX-License-Identifier: Apache-2.0
-# Version comparision utility extracted from pymaven and further stripped down
+# Version comparison utility extracted from pymaven and further stripped down
 # and significantly modified from the original at pymaven
+#
+# Visit https://aboutcode.org and https://github.com/nexB/univers for support and download.
 
 import functools
 from itertools import zip_longest

src/univers/rpm.py

@@ -1,13 +1,15 @@
 #
 # Copyright (c) SAS Institute Inc.
 # SPDX-License-Identifier: Apache-2.0
-# Version comparision utility extracted from python-rpm-vercmp and further
+# Version comparison utility extracted from python-rpm-vercmp and further
 # stripped down and significantly modified from the original at python-rpm-vercmp
+#
+# Visit https://aboutcode.org and https://github.com/nexB/univers for support and download.
 
 import re
 
 
-class Vercmp(object):
+class Vercmp:
     R_NONALNUMTILDE = re.compile(br"^([^a-zA-Z0-9~]*)(.*)$")
     R_NUM = re.compile(br"^([\d]+)(.*)$")
     R_ALPHA = re.compile(br"^([a-zA-Z]+)(.*)$")

src/univers/rpm.py.README

@@ -1,6 +1,6 @@
 Pure Python implementation of rpmvercmp.
 
-The RPM Package Manager (http://rpm.org) has a version comparision algorithm,
+The RPM Package Manager (http://rpm.org) has a version comparison algorithm,
 implemented in its C library, which performs the comparison in a certain way.
 
 In certain circumstances, where the C library is not installable (for example,