Disabling build-isolation in a pip config file

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Summary

The issue at hand is that setting no-build-isolation to true in a pip configuration file does not seem to disable build isolation as expected. This is causing a problem for a development machine without a network connection, where a periodic pip re-install of a Python library hangs due to pip attempting to check dependencies.

Root Cause

The root cause of this issue is that simply setting no-build-isolation to true in the pip config file is not sufficient to prevent pip from attempting to install build dependencies. The following factors contribute to this issue:

  • Misconfiguration: The install.no-build-isolation setting only prevents pip from isolating the build environment, but does not prevent it from checking for build dependencies.
  • Dependency Checking: The install.check-build-dependencies setting is not enough to prevent pip from checking for dependencies, as it only controls whether pip checks for dependencies during the build process.
  • Default Behavior: Pip’s default behavior is to attempt to install build dependencies, which can cause issues on machines without a network connection.

Why This Happens in Real Systems

This issue can occur in real systems where:

  • Network connectivity is limited: Machines without a network connection or with restricted access to the internet can experience issues with pip attempting to check dependencies.
  • Custom pip configurations: Users who customize their pip configurations to disable build isolation may still experience issues if they do not also configure other relevant settings.
  • Dependency-heavy projects: Projects with complex dependencies can be more prone to issues with pip attempting to install build dependencies.

Real-World Impact

The real-world impact of this issue includes:

  • Build failures: Pip attempts to install build dependencies can cause build failures on machines without a network connection.
  • Increased build time: Even if the build eventually succeeds, the attempt to install build dependencies can increase the overall build time.
  • Developer frustration: The issue can cause frustration for developers who are trying to work on projects with limited network connectivity.

Example or Code

pip config --site set install.no-dependencies true
pip config --site set install.no-build-isolation true
pip config --site set install.check-build-dependencies false
pip install -v ${PROJECT_ENV}

Note that even with these settings, pip may still attempt to install build dependencies.

How Senior Engineers Fix It

Senior engineers can fix this issue by:

  • Using the –no-dependencies flag: Always using the --no-dependencies flag when running pip install to prevent pip from attempting to install dependencies.
  • Configuring pip to use a local dependency cache: Configuring pip to use a local dependency cache can help prevent pip from attempting to install build dependencies over the network.
  • Customizing the pip configuration: Customizing the pip configuration to disable build isolation and dependency checking can help prevent issues on machines without a network connection.

Why Juniors Miss It

Junior engineers may miss this issue because:

  • Lack of experience with pip configurations: Junior engineers may not be familiar with the various pip configuration options and how they interact with each other.
  • Insufficient testing: Junior engineers may not thoroughly test their pip configurations to ensure that they are working as expected.
  • Overreliance on default behavior: Junior engineers may rely too heavily on pip’s default behavior and not take the time to customize their configurations to meet their specific needs.