Skip to content

Python 2.3

This section introduces Python 2.3 packaging metadata with PEP 314 and uses a small command-line project to show how early metadata fields described dependencies without installing them automatically.

Applied Project

Project Setup

The applied project is Historic Calculator, release 2.0.0. This snapshot is set in 2003, the release year of Python 2.3, and contains the historic_calculator package plus the hist_calc command-line script.

Run the Project

Application commands are documented in the section README.

Background

This project belongs to the Python 2.3 era in 2003, when packaging metadata became more expressive but installation stayed mostly manual. PEP 314 produced Metadata 1.1 and gave Python projects standard fields for describing package relationships:

  • Declaring required packages
  • Declaring the package or feature a distribution provides
  • Declaring older packages or versions a distribution replaces

The setup.py file records those metadata fields directly:

setup(
    name="historic_calculator",
    version="2.0.0",
    description="A historical Python 2.3 application",
    package_dir={"": "src"},
    packages=["historic_calculator"],
    requires=["Numeric (==24.0b2)"],
    provides=["historic_calculator (2.0.0)"],
    obsoletes=["historic_calculator (<2.0.0)"],
    scripts=["bin/hist_calc"],
)
  • name gives the distribution its package name.
  • version records the release number that build and install commands use.
  • description adds a short human-readable project summary to the package metadata.
  • package_dir maps packages to the src directory instead of the project root.
  • packages lists the Python package included in the distribution.
  • requires records the Numeric dependency as package metadata.
  • provides declares the distribution name and version this package provides.
  • obsoletes marks older Historic Calculator releases as replaced by this release.
  • scripts installs the bin/hist_calc launcher as an executable script.

Dependency Management

Overview

PEP 314 metadata was an important step toward standardized dependency descriptions, but the model still had important limits:

  • ⚠️ It did not resolve or install runtime dependencies.
  • ⚠️ Tools such as wheels, build isolation, lock files, and modern dependency resolvers did not exist yet.
  • ⚠️ Users still had to prepare much of the environment by hand.

Runtime and build dependencies

Use Dockerfile.devEnv for the Python 2.3 development environment. It keeps the historical interpreter and build tooling isolated from the host machine.

Numeric 24.0b2 is the runtime component that provides array-style calculations for this project. It is the predecessor of NumPy, and this release can name it in requires, but distutils still treats that information as descriptive only. A user must install Numeric before installing Historic Calculator, which shows the gap between dependency metadata and dependency installation.

Fetch and unpack Numeric 24.0b2:

wget -O Numeric-24.0b2.tar.gz "https://sourceforge.net/projects/numpy/files/OldFiles/Numeric-24.0b2.tar.gz/download"
tar -xzf Numeric-24.0b2.tar.gz

Build and install Numeric from its own setup.py:

cd Numeric-24.0b2 && python setup.py install

Build the package

Build the source distribution:

python setup.py sdist

Install the package

Install the package and the hist_calc launcher system wide:

python setup.py install