PoC: automatically create a pinned extra with dependencies pinned from the lock file

[radoering]

Pull Request Check List

Related-to: #7990
Requires: #9427

• Added tests for changed code.
• Updated documentation for changed code.

⚠️ This is a bit hacky and just a demonstration what's possible with #9427. I'm not even sure if we want such a feature or if it is better suited for a plugin...

It requires a lock file created with #9427 (which is included in this PR).

When running poetry build, an extra named pinned is automatically created¹. This extra requires the exact version of all locked dependencies from the main group. Since #9427 writes the resulting markers into the lock file, we can add the correct markers for each extra dependency.

Example core metadata generated for Poetry itself:

core metadata of Poetry with `pinned` extra

...
Provides-Extra: pinned
Requires-Dist: build (==1.2.1) ; extra == "pinned"
Requires-Dist: build (>=1.2.1,<2.0.0)
Requires-Dist: cachecontrol (==0.14.0) ; extra == "pinned"
Requires-Dist: cachecontrol[filecache] (>=0.14.0,<0.15.0)
Requires-Dist: certifi (==2024.2.2) ; extra == "pinned"
Requires-Dist: cffi (==1.16.0) ; extra == "pinned" and (sys_platform == "linux" and platform_python_implementation != "PyPy" or sys_platform == "darwin")
Requires-Dist: charset-normalizer (==3.3.2) ; extra == "pinned"
Requires-Dist: cleo (==2.1.0) ; extra == "pinned"
Requires-Dist: cleo (>=2.1.0,<3.0.0)
Requires-Dist: colorama (==0.4.6) ; extra == "pinned" and os_name == "nt"
Requires-Dist: crashtest (==0.4.1) ; extra == "pinned"
Requires-Dist: cryptography (==42.0.3) ; extra == "pinned" and sys_platform == "linux"
Requires-Dist: distlib (==0.3.8) ; extra == "pinned"
Requires-Dist: dulwich (==0.21.7) ; extra == "pinned"
Requires-Dist: dulwich (>=0.21.2,<0.22.0)
Requires-Dist: fastjsonschema (==2.19.1) ; extra == "pinned"
Requires-Dist: fastjsonschema (>=2.18.0,<3.0.0)
Requires-Dist: filelock (==3.13.1) ; extra == "pinned"
Requires-Dist: idna (==3.6) ; extra == "pinned"
Requires-Dist: importlib-metadata (==7.0.1) ; extra == "pinned" and python_version < "3.12"
Requires-Dist: importlib-metadata (>=4.4) ; python_version < "3.10"
Requires-Dist: importlib-resources (==6.1.1) ; extra == "pinned" and python_version < "3.9"
Requires-Dist: installer (==0.7.0) ; extra == "pinned"
Requires-Dist: installer (>=0.7.0,<0.8.0)
Requires-Dist: jaraco-classes (==3.3.1) ; extra == "pinned"
Requires-Dist: jeepney (==0.8.0) ; extra == "pinned" and sys_platform == "linux"
Requires-Dist: keyring (==24.3.1) ; extra == "pinned"
Requires-Dist: keyring (>=24.3.1,<25.0.0)
Requires-Dist: more-itertools (==10.2.0) ; extra == "pinned"
Requires-Dist: msgpack (==1.0.7) ; extra == "pinned"
Requires-Dist: packaging (==24.0) ; extra == "pinned"
Requires-Dist: packaging (>=24.0)
Requires-Dist: pexpect (==4.9.0) ; extra == "pinned"
Requires-Dist: pexpect (>=4.7.0,<5.0.0)
Requires-Dist: pkginfo (==1.10.0) ; extra == "pinned"
Requires-Dist: pkginfo (>=1.10,<2.0)
Requires-Dist: platformdirs (==4.2.0) ; extra == "pinned"
Requires-Dist: platformdirs (>=3.0.0,<5)
Requires-Dist: poetry-core @ git+https://github.com/radoering/poetry-core.git@markers/reduce-by-python-constraint
Requires-Dist: poetry-core @ git+https://github.com/radoering/poetry-core.git@markers/reduce-by-python-constraint ; extra == "pinned"
Requires-Dist: poetry-plugin-export (==1.8.0) ; extra == "pinned"
Requires-Dist: poetry-plugin-export (>=1.8.0,<2.0.0)
Requires-Dist: ptyprocess (==0.7.0) ; extra == "pinned"
Requires-Dist: pycparser (==2.21) ; extra == "pinned" and (sys_platform == "linux" and platform_python_implementation != "PyPy" or sys_platform == "darwin")
Requires-Dist: pyproject-hooks (==1.0.0) ; extra == "pinned"
Requires-Dist: pyproject-hooks (>=1.0.0,<2.0.0)
Requires-Dist: pywin32-ctypes (==0.2.2) ; extra == "pinned" and sys_platform == "win32"
Requires-Dist: rapidfuzz (==3.6.1) ; extra == "pinned"
Requires-Dist: requests (==2.31.0) ; extra == "pinned"
Requires-Dist: requests (>=2.26,<3.0)
Requires-Dist: requests-toolbelt (==1.0.0) ; extra == "pinned"
Requires-Dist: requests-toolbelt (>=1.0.0,<2.0.0)
Requires-Dist: secretstorage (==3.3.3) ; extra == "pinned" and sys_platform == "linux"
Requires-Dist: shellingham (==1.5.4) ; extra == "pinned"
Requires-Dist: shellingham (>=1.5,<2.0)
Requires-Dist: tomli (==2.0.1) ; extra == "pinned" and python_version < "3.11"
Requires-Dist: tomli (>=2.0.1,<3.0.0) ; python_version < "3.11"
Requires-Dist: tomlkit (==0.12.3) ; extra == "pinned"
Requires-Dist: tomlkit (>=0.11.4,<1.0.0)
Requires-Dist: trove-classifiers (==2024.1.31) ; extra == "pinned"
Requires-Dist: trove-classifiers (>=2022.5.19)
Requires-Dist: urllib3 (==2.2.0) ; extra == "pinned"
Requires-Dist: virtualenv (==20.25.0) ; extra == "pinned"
Requires-Dist: virtualenv (>=20.23.0,<21.0.0)
Requires-Dist: xattr (==1.1.0) ; extra == "pinned" and sys_platform == "darwin"
Requires-Dist: xattr (>=1.0.0,<2.0.0) ; sys_platform == "darwin"
Requires-Dist: zipp (==3.17.0) ; extra == "pinned" and python_version < "3.12"
...

¹ For the PoC, the extra is always created. If we decide to add this feature, we should introduce a flag, which is disabled by default.