wreck 0.2.2

Manage and fix requirements files for Python package authors

From .in requirement files generate and fix .lock and .unlock files

* Python 3.9 through 3.13, PyPy

new in 0.2.x

compatible release operator support; arbitrary equality issue UnResolvable;

new in 0.1.x

fork portion of drain-swamp;

What wreck?

Fix the requirements/constraint files and there would be little or no need to fix venvs

wreck is a homophone (same or similar pronunciation) of req, abbreviated form of requirement. The past tense of wreck is either wrecked or rekt; depending on how old you are.

Generates both lock and unlock requirement files. Fixes both! Minimizing the likelihood of dependency conflicts

Focus is on the requirements and constraints files, venv aware, but not dependent on venv. Not a venv manager.

Caters to authors of apps (lock) and packages (lock and unlock).

Gauge the demand

Frustrating

GIL and multithreading UX aside, resolving dependency conflicts is the next most frustrating issue facing Python coders

multiple venv

Often don’t consider there will be multiple venv, not always just one. So all requirements don’t apply to all venv

Easy learning curve

Configuration read from pyproject.toml. There is one section per venv. Then run one cli command per venv.

Unlike other packages, per .in file, produces two files: .unlock and .lock

For a particular venv, fixes all requirement files, rather than one file at a time

app and package authors

The needs of an app and a package author cannot be solved by a tool that caters only towards app authors

Not automatically resolved

For dependency conflicts, that can’t be automagically resolved, falls into these categories:

• unresolvable

  pip<24.2 and pip>=24.2 is unresolvable.

  One possible solution is to split requirements into multiple venv

• shared between multiple venv

  Ideally, code is kept DRY (don’t repeat yourself) as pragmatic. This applies equally to requirements and constraints.

  .shared.in constraints are included into many venv, special care must be taken.

  wreck deals with fixing requirements and constraints which apply to one venv at a time. When applies to multiple venv, wreck supports this, but can’t fix conflicts.

Configuration

In pyproject.toml, for each venv, add a [[tool.venv]] section.

[[tool.venvs]]
venv_base_path = '.venv'
reqs = [
    'requirements/dev',
    'requirements/kit',
    'requirements/pip',
    'requirements/pip-tools',
    'requirements/prod.shared',
    'requirements/manage',
    'requirements/mypy',
    'requirements/tox',
]

[[tool.venvs]]
venv_base_path = '.doc/.venv'
reqs = [
    'docs/requirements',
    'docs/pip-tools',
]

These are top most level requirement files without last suffix.

The additional requirements are for use by tox and CI/CD workflows.

• use posix relative paths

• assumed the venv are within the package base folder

• requirements and constraints files are not required to be in a subfolder, however it’s highly encouraged

package author

Possible corresponding dependency section

[tool.setuptools.dynamic]

dependencies = { file = ['requirements/prod.shared.unlock'] }
optional-dependencies.pip = { file = ['requirements/pip.lock'] }
optional-dependencies.pip_tools = { file = ['requirements/pip-tools.lock'] }
optional-dependencies.dev = { file = ['requirements/dev.lock'] }
optional-dependencies.manage = { file = ['requirements/manage.lock'] }
optional-dependencies.docs = { file = ['docs/requirements.lock'] }

Dependencies last suffix is .unlock

apps author

Possible corresponding dependency section

[tool.setuptools.dynamic]
dependencies = { file = ['requirements/prod.shared.lock'] }
optional-dependencies.pip = { file = ['requirements/pip.lock'] }
optional-dependencies.pip_tools = { file = ['requirements/pip-tools.lock'] }
optional-dependencies.dev = { file = ['requirements/dev.lock'] }
optional-dependencies.manage = { file = ['requirements/manage.lock'] }
optional-dependencies.docs = { file = ['docs/requirements.lock'] }

Dependencies last suffix is .lock

Usage

req fix --venv-relpath='.venv'
req fix --venv-relpath='.doc/.venv'

Provide path to the pyproject.toml if different location from cwd. Either the absolute path to the base folder or the file.

req fix --venv-relpath='.venv' --path=~/parent_folder/package_base_folder
req fix --venv-relpath='.venv' --path=~/parent_folder/package_base_folder/pyproject.toml

--venv-relpath does not support absolute path

Command options

reqs fix options

cli	default	description
-p/–path	cwd	absolute path to package base folder
-v/–venv-relpath	None	venv relative path. None implies all venv use the same python interpreter version
-t/–timeout	15	Web connection time in seconds
–show-unresolvables	True	For each venv, in a table print the unresolvable dependency conflicts
–show-fixed	True	For each venv, in a table print fixed issues
–show-resolvable-shared	True	For each venv in a table print resolvable issues that involve .shared.in files

Exit codes

0 – Evidently sufficient effort put into unittesting. Job well done, beer on me!

1 – Failures occurred. failed compiles report onto stderr

2 – entrypoint incorrect usage

3 – path given for config file reverse search cannot find a pyproject.toml file

4 – pyproject.toml config file parse issue. Expecting [[tool.venvs]] sections

5 – package pip-tools is required to lock package dependencies. Install it

6 – Missing some .in files. Support file(s) not checked

7 – venv base folder does not exist. Create it

8 – expecting [[tool.venvs]] field reqs to be a sequence

9 – No such venv found

10 – timeout occurred. Check web connection

Theory

Current theory

files

file	description
requirements-*.in	might contain pins. Maybe either a requirement or a constraints file
requirements-*.txt	output file consumable by pip

Difference between requirements and constraints

• constraints files cannot have lines with -e

• constraints files cannot have lines with extras e.g. coverage[toml]

• If needed, constraints are applied

wreck theory

The requirements- prefix is noisy, provides no useful info, ugly. It’s use is discouraged.

files

file	description
*.in	raw requirement or contraints file
*.shared.in	constraints file could be shared by more than one venv
*.lock	locked requirement file
*.unlock	unlocked requirement file

There is also *.shared.lock and *.shared.unlock

Document issues in the respective *.in and *.shared.in file. Every undocumented pin is bad UX.

The fixes of each dependency conflict issue should be separated into a pins-*[.shared].in file.

e.g. pins-ccfi.in or pins-myst-parser.in

When the crisis is over. Removed these files along with any links to them.

Market research

packages

package	description
pip-compile-multi	sync multiple calls produces lock files
uv	A venv manager. Offers cli options to resolve conflicts
poetry	venv manager and build backend. Complex config within pyproject.toml

base packages

package	description
pip-tools	does not sync multiple calls
pip	present actionable info. Includes an ugly traceback

not useful

package	description
pyp2req	venv unaware. Fixes nothing. Prints backend requires and top level dependencies to stdout

No package deals exclusively, effectively, and solely with requirements/constraint files. The top packages, which actual fixes dependency conflicts, are venv managers. Gives options to mitigate issues.

The top packages apply fixes to the venv, not the requirements/constraint files.

If the requirements/constraint files are fixed, there would be little or no need to fix venvs.

If anyone disagrees with these assessments of other packages, create an issue. Recommend a 1-2 line description

Known issues

Any/all known shortcomings are tracked within CHANGES.rst section Known regressions.

Accepted feature requests are tracked within CHANGES.rst section Feature request. There should also be a cooresponding issue.

License

aGPLv3+

The short ramifications are:

• commercial/public entities must obtain a license waiver

Meaning pay to support the project and towards funding ongoing package maintainance.

• Do not change the copyright notice; that’s serious IP theft.