Describe the bug
Running tests in parallel and comining the results afterwards using coverage combine can lead to a Permission denied while trying to read one of the previously created .coverage... files.
Traceback
Traceback (most recent call last):
File "/.../zdaemon/.tox/coverage/bin/coverage", line 10, in <module>
sys.exit(main())
^^^^^^
File "/.../zdaemon/.tox/coverage/lib/python3.11/site-packages/coverage/cmdline.py", line 1141, in main
status = CoverageScript().command_line(argv)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/.../zdaemon/.tox/coverage/lib/python3.11/site-packages/coverage/cmdline.py", line 841, in command_line
self.coverage.combine(data_paths, strict=True, keep=bool(options.keep))
File "/.../zdaemon/.tox/coverage/lib/python3.11/site-packages/coverage/control.py", line 906, in combine
combine_parallel_data(
File "/.../zdaemon/.tox/coverage/lib/python3.11/site-packages/coverage/data.py", line 162, in combine_parallel_data
with open(f, "rb") as fobj:
^^^^^^^^^^^^^
PermissionError: [Errno 13] Permission denied: '/.../zdaemon/.coverage.echo-6.local.49253.XxJfFKGx'
I traced down the version needed for this issue to happen to version 7.12.1b1 and newer.
To Reproduce
I have no idea (yet) how to reproduce it but the diff of version 7.12.1b1 to the previous one is not too big and maybe this report already rings a bell.
For now I only have a failing CI job as a reference: https://github.com/zopefoundation/zdaemon/actions/runs/20894903261/job/60031864188
Answer the questions below:
- What version of Python are you using? 3.11, 3.12
- What version of coverage.py shows the problem? 7.12.1b1 and newer
- The output of
coverage debug sys is helpful.
coverage debug sys
-- sys -------------------------------------------------------
coverage_version: 7.12.1b1
coverage_module: /.../zdaemon/.tox/coverage/lib/python3.11/site-packages/coverage/__init__.py
core: -none-
CTracer: available from /.../zdaemon/.tox/coverage/lib/python3.11/site-packages/coverage/tracer.cpython-311-darwin.so
plugins.file_tracers: -none-
plugins.configurers: -none-
plugins.context_switchers: -none-
configs_attempted: /.../zdaemon/.coveragerc
/.../zdaemon/setup.cfg
/.../zdaemon/tox.ini
/.../zdaemon/pyproject.toml
configs_read: /.../zdaemon/setup.cfg
/.../zdaemon/tox.ini
/.../zdaemon/pyproject.toml
config_file: /.../zdaemon/pyproject.toml
config_contents: b'# Generated with zope.meta (https://zopemeta.readthedocs.io/) from:\n# https://github.com/zopefoundation/meta/tree/master/src/zope/meta/buildout-recipe\n#\n# Generated from:\n# https://github.com/zopefoundation/meta/tree/master/config/buildout-recipe\n\n[build-system]\nrequires = [\n "setuptools >= 78.1.1,< 81",\n "wheel",\n]\nbuild-backend = "setuptools.build_meta"\n\n[tool.coverage.run]\nbranch = true\nsource = ["zdaemon"]\nparallel = true\ndata_file = "$COVERAGE_HOME.coverage"\nomit = ["*/__main__.py"]\n\n[tool.coverage.report]\nfail_under = 79\nprecision = 2\nignore_errors = true\nshow_missing = true\nexclude_lines = [\n "pragma: no cover",\n "pragma: nocover",\n "except ImportError:",\n "raise NotImplementedError",\n "if __name__ == \'__main__\':",\n "self.fail",\n "raise AssertionError",\n "raise unittest.Skip",\n]\n\n[tool.coverage.html]\ndirectory = "parts/htmlcov"\n\n[tool.coverage.paths]\nsource = [\n "src/",\n ".tox/*/lib/python*/site-packages/",\n ".tox/pypy*/site-packages/",\n]\n'
data_file: -none-
python: 3.11.14 (main, Oct 11 2025, 02:11:58) [Clang 17.0.0 (clang-1700.3.19.1)]
platform: macOS-26.2-arm64-arm-64bit
implementation: CPython
build: main
Oct 11 2025 02:11:58
gil_enabled: True
executable: /.../zdaemon/.tox/coverage/bin/python3
def_encoding: utf-8
fs_encoding: utf-8
pid: 67863
cwd: /.../zdaemon
path: /.../zdaemon/.tox/coverage/bin
/opt/local/Library/Frameworks/Python.framework/Versions/3.11/lib/python311.zip
/opt/local/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11
/opt/local/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/lib-dynload
/.../zdaemon/.tox/coverage/lib/python3.11/site-packages
/.../zdaemon/src
environment: HOME = /Users/m.howitz
command_line: ./.tox/coverage/bin/coverage debug sys
time: 2026-01-14 17:04:58
4. What versions of what packages do you have installed? The output of `pip freeze` is helpful.
pip freeze
coverage==7.12.1b1
manuel==1.13.0
setuptools==80.9.0
zc.customdoctests==1.0.1
ZConfig==4.3
zdaemon @ file:///.../zdaemon/.tox/.tmp/package/106/zdaemon-5.3.dev0-0.editable-py3-none-any.whl#sha256=34aef2af782542507f8ac1a6e4d9f20c860ab0187ee53d8db675c66b87e2de64
zope.exceptions==6.0
zope.interface==8.2
zope.testing==6.1
zope.testrunner==8.1
- What code shows the problem? It is happening on
master, commit 2996a8c02f8af214431a8ef096112ba18d4909a9 (the last one there, which is from 6 month ago)
- What commands should we run to reproduce the problem?
git clone git@github.com:zopefoundation/zdaemoncd zdaemongit checkout 2996a8c02f8af214431a8ef096112ba18d4909a9python3.11 -m venv .venv.venv/bin/pip install tox.venv/bin/tox -ecoverage
Expected behavior
Successful coverage combine after the test run.
Additional context
Problem occurs on MacOS (locally) as well as on Ubuntu (GitHub Actions).
Describe the bug
Running tests in parallel and comining the results afterwards using
coverage combinecan lead to aPermission deniedwhile trying to read one of the previously created.coverage...files.Traceback
I traced down the version needed for this issue to happen to version 7.12.1b1 and newer.
To Reproduce
I have no idea (yet) how to reproduce it but the diff of version 7.12.1b1 to the previous one is not too big and maybe this report already rings a bell.
For now I only have a failing CI job as a reference: https://github.com/zopefoundation/zdaemon/actions/runs/20894903261/job/60031864188
Answer the questions below:
coverage debug sysis helpful.coverage debug sys
pip freeze
master, commit2996a8c02f8af214431a8ef096112ba18d4909a9(the last one there, which is from 6 month ago)git clone git@github.com:zopefoundation/zdaemoncd zdaemongit checkout 2996a8c02f8af214431a8ef096112ba18d4909a9python3.11 -m venv .venv.venv/bin/pip install tox.venv/bin/tox -ecoverageExpected behavior
Successful
coverage combineafter the test run.Additional context
Problem occurs on MacOS (locally) as well as on Ubuntu (GitHub Actions).