🐛 fix(provision): serialize concurrent provisioning#3756
Merged
gaborbernat merged 1 commit intotox-dev:mainfrom Feb 18, 2026
Merged
🐛 fix(provision): serialize concurrent provisioning#3756gaborbernat merged 1 commit intotox-dev:mainfrom
gaborbernat merged 1 commit intotox-dev:mainfrom
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Multiple tox processes running simultaneously would corrupt the shared provision environment (.tox/.tox) because setup and execution had no cross-process coordination. One process could delete or modify the virtualenv while another was actively using it, causing import errors like missing pip modules. Wrapping the provision lifecycle with a FileLock follows the same pattern already used by PackageToxEnv for package environments. The lock covers setup through execution to prevent a concurrent process from cleaning and recreating the env mid-run.
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When multiple tox processes run concurrently and provisioning is required (via
requires), they all attempt to create and populate the same.tox/.toxprovision environment without any coordination. 🔒 One process can delete or overwrite virtualenv files while another is actively importing from them, causingModuleNotFoundErrorcrashes like missingpip._vendormodules.The provision environment is a
RunToxEnv, which unlikePackageToxEnvhas no file-based locking. Rather than adding locking to allRunToxEnvinstances, wrapping just therun_provisionlifecycle with aFileLockon{env_dir}/file.lockfollows the existing pattern already used by packaging environments. The lock covers setup through execution so a second process waits until the first finishes before attempting its own provisioned run.This uses the same
file.lockconvention that_clean()already preserves viaensure_empty_dir(env_dir, except_filename="file.lock"), so the lock file survives environment recreation.Fixes #2515