ENH: modernize package configuration

.github/dependabot.yml

@@ -0,0 +1,7 @@
+version: 2
+
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: yearly

.github/workflows/cd.yml

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+name: CD
+
+on:
+  release:
+    types:
+      - prereleased
+      - released
+
+jobs:
+  package-name:
+    uses: ComPWA/actions/.github/workflows/get-pypi-name.yml@99e91bcc486218c7dbbb4f2e0319bfcb028562aa # 4.0.1
+  pypi:
+    environment:
+      name: PyPI
+      url: https://pypi.org/p/${{ needs.package-name.outputs.name }}
+    if: startsWith(github.ref, 'refs/tags')
+    name: Publish to PyPI
+    needs:
+      - package-name
+    permissions:
+      id-token: write
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: ComPWA/actions/build-pypi-distribution@99e91bcc486218c7dbbb4f2e0319bfcb028562aa # 4.0.1
+      - uses: pypa/gh-action-pypi-publish@dc37677b2e1c63e2034f94d8a5b11f265b73ba33 # v1.14.2

.github/workflows/ci.yml

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+name: CI
+
+env:
+  FORCE_COLOR: yes
+
+on:
+  pull_request:
+    branches:
+      - 1.4.x
+  push:
+    branches:
+      - 1.4.x
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != format('refs/heads/{0}', github.event.repository.default_branch) }}
+
+jobs:
+  test:
+    name: Test Python ${{ matrix.python-version }}
+    runs-on: ubuntu-24.04
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version:
+          - "3.10"
+          - "3.11"
+          - "3.12"
+          - "3.13"
+          - "3.14"
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: astral-sh/setup-uv@c771a70e6277c0a99b617c7a806ffedaca235ff9 # v9.0.0
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Run tests
+        run: uv run --no-project --with pytest python -m pytest -q
+
+  distribution:
+    name: Build and inspect distributions
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: astral-sh/setup-uv@c771a70e6277c0a99b617c7a806ffedaca235ff9 # v9.0.0
+        with:
+          python-version: "3.14"
+      - name: Build wheel and source distribution
+        run: uv build
+      - name: Check distribution metadata
+        run: uvx twine check dist/*
+      - name: Prepare isolated wheel tests
+        run: |
+          mkdir -p "${{ runner.temp }}/wheel-test"
+          cp -R tests "${{ runner.temp }}/wheel-test/"
+      - name: Test the installed wheel
+        working-directory: ${{ runner.temp }}/wheel-test
+        run: >-
+          uv run
+          --isolated
+          --no-project
+          --with "${{ github.workspace }}"/dist/*.whl
+          --with pytest
+          python -m pytest -q

.gitignore

@@ -58,3 +58,14 @@ target/
 
 # PyCharm / Intellij
 .idea/
+
+# Virtual environments
+.venv/
+uv.lock
+
+# Agent configuration
+/.agents/
+/.claude/
+/.codex/
+/AGENTS.md
+/CLAUDE.md

README.md

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+[![CI](https://github.com/ComPWA/python-constraint/actions/workflows/ci.yml/badge.svg)](https://github.com/ComPWA/python-constraint/actions/workflows/ci.yml)
+
+# compwa-python-constraint
+
+> [!NOTE]
+> This is a packaging fork of [python-constraint 1.4.0](https://github.com/python-constraint/python-constraint/tree/1.4.0), maintained by the [ComPWA project](https://compwa.github.io). It is published as [compwa-python-constraint](https://pypi.org/project/compwa-python-constraint), but preserves the public `constraint` import package and the behavior of the upstream 1.4.0 solver.
+
+## Why this fork exists
+
+The upstream 1.4.0 release on
+[PyPI](https://pypi.org/project/python-constraint/1.4.0) provides only a
+`.tar.bz2` source distribution.
+[PEP 625](https://peps.python.org/pep-0625/) standardized source distributions
+as gzip-compressed `.tar.gz` archives. In version 0.12.0,
+[uv stopped accepting legacy source-distribution formats](https://github.com/astral-sh/uv/releases/tag/0.12.0#breaking-changes),
+including `.tar.bz2`, and recommends rebuilding affected packages as `.tar.gz`
+archives.
+
+This fork makes that packaging-only update so projects can continue using the
+1.4.0 implementation with current Python packaging tools. Its declarative
+`pyproject.toml` build produces:
+
+- a pure-Python `py3-none-any` wheel, which installers can use without a local
+  build step; and
+- a standards-compliant `.tar.gz` source distribution as a fallback.
+
+The distribution is versioned as `1.4.0.post1` to identify it as a downstream
+packaging revision. Solver changes continue to belong in the
+[upstream project](https://github.com/python-constraint/python-constraint).
+
+## Introduction
+
+The Python constraint module offers solvers for
+[Constraint Satisfaction Problems (CSPs)](https://en.wikipedia.org/wiki/Constraint_satisfaction_problem)
+over finite domains in simple and pure Python. A CSP can be represented in
+terms of variables, their possible domains, and constraints between them.
+
+## Examples
+
+### Basics
+
+```python
+>>> from constraint import *
+>>> problem = Problem()
+>>> problem.addVariable("a", [1, 2, 3])
+>>> problem.addVariable("b", [4, 5, 6])
+>>> problem.getSolutions()
+[{'a': 3, 'b': 6}, {'a': 3, 'b': 5}, {'a': 3, 'b': 4},
+ {'a': 2, 'b': 6}, {'a': 2, 'b': 5}, {'a': 2, 'b': 4},
+ {'a': 1, 'b': 6}, {'a': 1, 'b': 5}, {'a': 1, 'b': 4}]
+
+>>> problem.addConstraint(lambda a, b: a * 2 == b, ("a", "b"))
+>>> problem.getSolutions()
+[{'a': 3, 'b': 6}, {'a': 2, 'b': 4}]
+
+>>> problem = Problem()
+>>> problem.addVariables(["a", "b"], [1, 2, 3])
+>>> problem.addConstraint(AllDifferentConstraint())
+>>> problem.getSolutions()
+[{'a': 3, 'b': 2}, {'a': 3, 'b': 1}, {'a': 2, 'b': 3},
+ {'a': 2, 'b': 1}, {'a': 1, 'b': 2}, {'a': 1, 'b': 3}]
+```
+
+### Rooks problem
+
+```python
+>>> problem = Problem()
+>>> numpieces = 8
+>>> cols = range(numpieces)
+>>> rows = range(numpieces)
+>>> problem.addVariables(cols, rows)
+>>> for col1 in cols:
+...     for col2 in cols:
+...         if col1 < col2:
+...             problem.addConstraint(
+...                 lambda row1, row2: row1 != row2,
+...                 (col1, col2),
+...             )
+>>> solutions = problem.getSolutions()
+```
+
+### Magic squares
+
+```python
+>>> problem = Problem()
+>>> problem.addVariables(range(16), range(1, 17))
+>>> problem.addConstraint(AllDifferentConstraint(), range(16))
+>>> problem.addConstraint(ExactSumConstraint(34), [0, 5, 10, 15])
+>>> problem.addConstraint(ExactSumConstraint(34), [3, 6, 9, 12])
+>>> for row in range(4):
+...     problem.addConstraint(
+...         ExactSumConstraint(34),
+...         [row * 4 + i for i in range(4)],
+...     )
+>>> for col in range(4):
+...     problem.addConstraint(
+...         ExactSumConstraint(34),
+...         [col + 4 * i for i in range(4)],
+...     )
+>>> solutions = problem.getSolutions()
+```
+
+## Features
+
+The following solvers are available:
+
+- Backtracking solver
+- Recursive backtracking solver
+- Minimum conflicts solver
+
+Predefined constraint types include:
+
+- `FunctionConstraint`
+- `AllDifferentConstraint`
+- `AllEqualConstraint`
+- `ExactSumConstraint`
+- `MaxSumConstraint`
+- `MinSumConstraint`
+- `InSetConstraint`
+- `NotInSetConstraint`
+- `SomeInSetConstraint`
+- `SomeNotInSetConstraint`
+
+## Installation
+
+```shell
+python -m pip install compwa-python-constraint
+```
+
+The distribution name is `compwa-python-constraint`, while the import remains
+unchanged:
+
+```python
+from constraint import Problem
+```
+
+## Upstream project
+
+`python-constraint` was written by Gustavo Niemeyer and is maintained at
+[python-constraint/python-constraint](https://github.com/python-constraint/python-constraint).
+Please report solver bugs and propose behavioral changes
+[upstream](https://github.com/python-constraint/python-constraint/issues).
+
+For packaging issues specific to this fork, use the
+[ComPWA issue tracker](https://github.com/ComPWA/python-constraint/issues).