Upgrade Guides

Upgrading 8.3.X to 9.0

This is under active construction and will not be finalized until 9.0.0 is released.

This guide assumes the user is on version 8.3.X.

Deprecations

For each deprecation, provide a brief explanation, and direct users to new function / class if available.

• CliRunner.isolated_filesystem() is deprecated and will be removed in Click 9.0. The helper predates Python 3 and modern pytest, and it relies on os.chdir, which mutates process-global state and is therefore not thread-safe. Replace it with a temporary directory (tempfile.TemporaryDirectory, or pytest’s tmp_path fixture) and pass absolute paths to the command instead of relying on the current working directory. To run commands in parallel, use process-based isolation (such as pytest-xdist) rather than threads, since CliRunner.invoke() also redirects the process-global standard streams and other interpreter-wide state. See #3700, #3501 and the testing guide.

Removals with prior deprecation

For each removal, provide a brief explanation, and direct users to new function / class if available. If possible, deprecate and remove in 10.0.0, rather than removing outright.

• TBD

Removals with no prior deprecation

The changes were not able to be deprecated prior to removal. Explain clearly why then were not able to be deprecated first.

• TBD

Changes

• TBD

Fixes

• TBD