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title="Replaced by another succeeding PEP">Superseded</abbr></dd> <dt class="field-odd">Type:</dt> <dd class="field-odd"><abbr title="Normative PEP with a new feature for Python, implementation change for CPython or interoperability standard for the ecosystem">Standards Track</abbr></dd> <dt class="field-even">Topic:</dt> <dd class="field-even"><a class="reference external" href="../topic/packaging/">Packaging</a></dd> <dt class="field-odd">Created:</dt> <dd class="field-odd">20-Aug-2020</dd> <dt class="field-even">Post-History:</dt> <dd class="field-even">20-Aug-2020</dd> <dt class="field-odd">Superseded-By:</dt> <dd class="field-odd"><a class="reference external" href="../pep-0621/">621</a></dd> <dt class="field-even">Resolution:</dt> <dd class="field-even"><a class="reference external" href="https://discuss.python.org/t/how-to-specify-dependencies-pep-508-strings-or-a-table-in-toml/5243/38">Discourse message</a></dd> </dl> <hr class="docutils" /> <section id="contents"> <details><summary>Table of Contents</summary><ul class="simple"> <li><a class="reference internal" href="#abstract">Abstract</a></li> <li><a class="reference internal" href="#entries">Entries</a></li> <li><a class="reference internal" href="#specification">Specification</a><ul> <li><a class="reference internal" href="#dependencies">dependencies</a></li> <li><a class="reference internal" href="#optional-dependencies">optional-dependencies</a></li> </ul> </li> <li><a class="reference internal" href="#example">Example</a></li> <li><a class="reference internal" href="#implementation">Implementation</a><ul> <li><a class="reference internal" href="#parsing">Parsing</a></li> <li><a class="reference internal" href="#metadata">Metadata</a></li> </ul> </li> <li><a class="reference internal" href="#copyright">Copyright</a></li> </ul> </details></section> <section id="abstract"> <h2><a class="toc-backref" href="#abstract" role="doc-backlink">Abstract</a></h2> This PEP specifies how to write a project’s dependencies in a <code class="docutils literal notranslate">pyproject.toml</code> file for packaging-related tools to consume using the <a class="pep reference internal" href="../pep-0621/#dependencies-optional-dependencies" title="PEP 621 – Storing project metadata in pyproject.toml § dependencies/optional-dependencies">fields defined in PEP 621</a>. <div class="admonition note"> Note This PEP has been accepted and was merged into <a class="pep reference internal" href="../pep-0621/" title="PEP 621 – Storing project metadata in pyproject.toml">PEP 621</a>. </div> </section> <section id="entries"> <h2><a class="toc-backref" href="#entries" role="doc-backlink">Entries</a></h2> All dependency entries MUST be valid <a class="pep reference internal" href="../pep-0508/" title="PEP 508 – Dependency specification for Python Software Packages">PEP 508 strings</a>. Build backends SHOULD abort at load time for any parsing errors. <div class="highlight-default notranslate"><div class="highlight"><pre>from packaging.requirements import InvalidRequirement, Requirement ... try: Requirement(entry) except InvalidRequirement: # exit </pre></div> </div> </section> <section id="specification"> <h2><a class="toc-backref" href="#specification" role="doc-backlink">Specification</a></h2> <section id="dependencies"> <h3><a class="toc-backref" href="#dependencies" role="doc-backlink">dependencies</a></h3> <ul class="simple"> <li>Format: array of strings</li> <li>Related core metadata:<ul> <li><a class="reference external" href="https://packaging.python.org/specifications/core-metadata/#requires-dist-multiple-use">Requires-Dist</a></li> </ul> </li> </ul> Every element MUST be an <a class="reference external" href="#entries">entry</a>. <div class="highlight-default notranslate"><div class="highlight"><pre>[project] dependencies = [ 'PyYAML ~= 5.0', 'requests[security] < 3', 'subprocess32; python_version < "3.2"', ] </pre></div> </div> </section> <section id="optional-dependencies"> <h3><a class="toc-backref" href="#optional-dependencies" role="doc-backlink">optional-dependencies</a></h3> <ul class="simple"> <li>Format: table</li> <li>Related core metadata:<ul> <li><a class="reference external" href="https://packaging.python.org/specifications/core-metadata/#provides-extra-multiple-use">Provides-Extra</a></li> <li><a class="reference external" href="https://packaging.python.org/specifications/core-metadata/#requires-dist-multiple-use">Requires-Dist</a></li> </ul> </li> </ul> Each key is the name of the provided option, with each value being the same type as the <a class="reference external" href="#dependencies">dependencies</a> field i.e. an array of strings. <div class="highlight-default notranslate"><div class="highlight"><pre>[project.optional-dependencies] tests = [ 'coverage>=5.0.3', 'pytest', 'pytest-benchmark[histogram]>=3.2.1', ] </pre></div> </div> </section> </section> <section id="example"> <h2><a class="toc-backref" href="#example" role="doc-backlink">Example</a></h2> This is a real-world example port of what <a class="reference external" href="https://github.com/docker/compose/blob/789bfb0e8b2e61f15f423d371508b698c64b057f/setup.py#L28-L61">docker-compose</a> defines. <div class="highlight-default notranslate"><div class="highlight"><pre>[project] dependencies = [ 'cached-property >= 1.2.0, < 2', 'distro >= 1.5.0, < 2', 'docker[ssh] >= 4.2.2, < 5', 'dockerpty >= 0.4.1, < 1', 'docopt >= 0.6.1, < 1', 'jsonschema >= 2.5.1, < 4', 'PyYAML >= 3.10, < 6', 'python-dotenv >= 0.13.0, < 1', 'requests >= 2.20.0, < 3', 'texttable >= 0.9.0, < 2', 'websocket-client >= 0.32.0, < 1', # Conditional 'backports.shutil_get_terminal_size == 1.0.0; python_version < "3.3"', 'backports.ssl_match_hostname >= 3.5, < 4; python_version < "3.5"', 'colorama >= 0.4, < 1; sys_platform == "win32"', 'enum34 >= 1.0.4, < 2; python_version < "3.4"', 'ipaddress >= 1.0.16, < 2; python_version < "3.3"', 'subprocess32 >= 3.5.4, < 4; python_version < "3.2"', ] [project.optional-dependencies] socks = [ 'PySocks >= 1.5.6, != 1.5.7, < 2' ] tests = [ 'ddt >= 1.2.2, < 2', 'pytest < 6', 'mock >= 1.0.1, < 4; python_version < "3.4"', ] </pre></div> </div> </section> <section id="implementation"> <h2><a class="toc-backref" href="#implementation" role="doc-backlink">Implementation</a></h2> <section id="parsing"> <h3><a class="toc-backref" href="#parsing" role="doc-backlink">Parsing</a></h3> <div class="highlight-default notranslate"><div class="highlight"><pre>from packaging.requirements import InvalidRequirement, Requirement def parse_dependencies(config): dependencies = config.get('dependencies', []) if not isinstance(dependencies, list): raise TypeError('Field `project.dependencies` must be an array') for i, entry in enumerate(dependencies, 1): if not isinstance(entry, str): raise TypeError(f'Dependency #{i} of field `project.dependencies` must be a string') try: Requirement(entry) except InvalidRequirement as e: raise ValueError(f'Dependency #{i} of field `project.dependencies` is invalid: {e}') return dependencies def parse_optional_dependencies(config): optional_dependencies = config.get('optional-dependencies', {}) if not isinstance(optional_dependencies, dict): raise TypeError('Field `project.optional-dependencies` must be a table') optional_dependency_entries = {} for option, dependencies in optional_dependencies.items(): if not isinstance(dependencies, list): raise TypeError( f'Dependencies for option `{option}` of field ' '`project.optional-dependencies` must be an array' ) entries = [] for i, entry in enumerate(dependencies, 1): if not isinstance(entry, str): raise TypeError( f'Dependency #{i} of option `{option}` of field ' '`project.optional-dependencies` must be a string' ) try: Requirement(entry) except InvalidRequirement as e: raise ValueError( f'Dependency #{i} of option `{option}` of field ' f'`project.optional-dependencies` is invalid: {e}' ) else: entries.append(entry) optional_dependency_entries[option] = entries return optional_dependency_entries </pre></div> </div> </section> <section id="metadata"> <h3><a class="toc-backref" href="#metadata" role="doc-backlink">Metadata</a></h3> <div class="highlight-default notranslate"><div class="highlight"><pre>def construct_metadata_file(metadata_object): """ https://packaging.python.org/specifications/core-metadata/ """ metadata_file = 'Metadata-Version: 2.1\n' ... if metadata_object.dependencies: # Sort dependencies to ensure reproducible builds for dependency in sorted(metadata_object.dependencies): metadata_file += f'Requires-Dist: {dependency}\n' if metadata_object.optional_dependencies: # Sort extras and dependencies to ensure reproducible builds for option, dependencies in sorted(metadata_object.optional_dependencies.items()): metadata_file += f'Provides-Extra: {option}\n' for dependency in sorted(dependencies): if ';' in dependency: metadata_file += f'Requires-Dist: {dependency} and extra == "{option}"\n' else: metadata_file += f'Requires-Dist: {dependency}; extra == "{option}"\n' ... return metadata_file </pre></div> </div> </section> </section> <section id="copyright"> <h2><a class="toc-backref" href="#copyright" role="doc-backlink">Copyright</a></h2> This document is placed in the public domain or under the CC0-1.0-Universal license, whichever is more permissive. </section> </section> <hr class="docutils" /> Source: <a class="reference external" href="https://github.com/python/peps/blob/main/peps/pep-0631.rst">https://github.com/python/peps/blob/main/peps/pep-0631.rst</a> Last modified: <a class="reference external" href="https://github.com/python/peps/commits/main/peps/pep-0631.rst">2023-09-09 17:39:29 GMT</a> </article> <nav id="pep-sidebar"> <h2>Contents</h2> <ul> <li><a class="reference internal" href="#abstract">Abstract</a></li> <li><a class="reference internal" href="#entries">Entries</a></li> <li><a class="reference internal" href="#specification">Specification</a><ul> <li><a class="reference internal" href="#dependencies">dependencies</a></li> <li><a class="reference internal" href="#optional-dependencies">optional-dependencies</a></li> </ul> </li> <li><a class="reference internal" href="#example">Example</a></li> <li><a class="reference internal" href="#implementation">Implementation</a><ul> <li><a class="reference internal" href="#parsing">Parsing</a></li> <li><a class="reference internal" href="#metadata">Metadata</a></li> </ul> </li> <li><a class="reference internal" href="#copyright">Copyright</a></li> </ul> <a id="source" href="https://github.com/python/peps/blob/main/peps/pep-0631.rst">Page Source (GitHub)</a> </nav> </section> <script src="../_static/colour_scheme.js"></script> <script src="../_static/wrap_tables.js"></script> <script src="../_static/sticky_banner.js"></script> </body> </html>