`poetry install` is resulting in Deadlock exceptions with sdists on readthedocs

[danyeaw]

Description

Hi all,

I am having trouble with intermittent but consistent deadlock errors while running poetry install on the readthedocs runners. I have a few packages that are built from sdists including pygobject, pycairo, and pygobject-stubs. This was originally resulting in BadZip errors (even though the sdists are in a tarball.

For troubleshooting I turned on verbose mode with poetry install -vv, which shows a deadlock stack trace around which looks like it is caused by virtualenv loading all activation plugins eagerly via entry points, and something about doing that inside Poetry's isolated_builder context is causing a reentrant import deadlock on virtualenv.activation.powershell. Since this error happens intermittently (but frequently), I expect there is a race condition between the threads.

I tried changing Python versions and setting poetry config installer.no-binary pycairo,pygobject which didn't change things. However, I haven't been able to reproduce this locally, so getting a smaller reproducible example has been difficult. Since this error started happening over the last few months, I could also try to isolate the error to a specific Poetry version.

An example build is here: https://app.readthedocs.org/projects/gaphor-es/builds/32132330/

My readthedocs config:

version: 2
formats:
- htmlzip
- epub
build:
  os: ubuntu-24.04
  tools:
    python: "3.14"
  apt_packages:
  - libgirepository-2.0-dev
  - libcairo2-dev
  - pkg-config
  - python3-dev
  - gir1.2-pango-1.0
  - graphviz
  jobs:
    pre_install:
    - python3 -m pip install --upgrade pip
    - python3 -m pip install --constraint=.github/github-requirements.txt poetry
    - poetry config virtualenvs.create false
    post_install:
    - VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install -vv --with docs --no-interaction
sphinx:
  configuration: docs/conf.py
  fail_on_warning: true

Workarounds

Rerunning the workflow often fixes the issue.

Poetry Installation Method

pip

Operating System

Ubuntu 24.04

Poetry Version

Poetry (version 2.3.3)

Poetry Configuration

[rtd-command-info] start-time: 2026-04-06T12:18:52.178680Z, end-time: 2026-04-06T12:18:52.816827Z, duration: 0, exit-code: 0
poetry config --list
cache-dir = "/home/docs/.cache/pypoetry"
data-dir = "/home/docs/.local/share/pypoetry"
installer.max-workers = null
installer.no-binary = null
installer.only-binary = null
installer.parallel = true
installer.re-resolve = false
keyring.enabled = true
python.installation-dir = "{data-dir}/python"  # /home/docs/.local/share/pypoetry/python
requests.max-retries = 0
solver.lazy-wheel = true
system-git-client = false
virtualenvs.create = false
virtualenvs.in-project = null
virtualenvs.options.always-copy = false
virtualenvs.options.no-pip = false
virtualenvs.options.system-site-packages = false
virtualenvs.path = "{cache-dir}/virtualenvs"  # /home/docs/.cache/pypoetry/virtualenvs
virtualenvs.prompt = "{project_name}-py{python_version}"
virtualenvs.use-poetry-python = false

Python Sysconfig

sysconfig.log

python_sysconfig.txt

Example pyproject.toml

[project]
name = "gaphor"
version = "3.2.0"
description = "Gaphor is the simple modeling tool written in Python."
authors = [
    { name = "Arjan Molenaar", email = "gaphor@gmail.com" },
    { name = "Dan Yeaw", email = "dan@yeaw.me" },
]

readme = "README.md"

keywords = ["GTK", "diagram", "UML", "MBSE", "modeling"]

classifiers = [
    "Development Status :: 5 - Production/Stable",
    "Environment :: X11 Applications :: GTK",
    "Environment :: MacOS X",
    "Environment :: Win32 (MS Windows)",
    "Intended Audience :: Developers",
    "Intended Audience :: End Users/Desktop",
    "Intended Audience :: Information Technology",
    "License :: OSI Approved :: Apache Software License",
    "Operating System :: MacOS :: MacOS X",
    "Operating System :: Microsoft :: Windows",
    "Operating System :: POSIX",
    "Operating System :: Unix",
    "Programming Language :: Python",
    "Topic :: Desktop Environment :: Gnome",
    "Topic :: Multimedia :: Graphics :: Editors :: Vector-Based",
    "Topic :: Software Development :: Documentation",
]

requires-python = ">=3.12,<3.15"

dependencies = [
    "pycairo>=1.22.0",
    "PyGObject>=3.52",
    "gaphas>=5.1",
    "generic>=1.0.0",
    "tinycss2>=1.0.2",
    "babel>=2.10.3",
    "jedi (>=0.18.1,<0.20.0)",
    "better-exceptions>=0.3.3",
    "pydot>=1.4.2",
    "pillow>=10.0.0",
    "defusedxml>=0.7.1",
    "pyobjc-framework-cocoa (>=9.0.1) ; sys_platform == 'darwin'",
    "dulwich>=0.25.0",
]

[project.scripts]
gaphor = "gaphor.main:main"

[project.urls]
homepage = "https://gaphor.org/"
repository = "https://github.com/gaphor/gaphor"
documentation = "https://docs.gaphor.org/"

[project.entry-points."gaphor.appservices"]
"event_manager" = "gaphor.core.eventmanager:EventManager"
"module_loader" = "gaphor.services.moduleloader:ModuleLoader"
"app_file_manager" = "gaphor.ui.appfilemanager:AppFileManager"
"styling" = "gaphor.ui.styling:Styling"
"greeter" = "gaphor.ui.greeter:Greeter"
"help" = "gaphor.ui.help:HelpService"
"self_test" = "gaphor.ui.selftest:SelfTest"

[project.entry-points."gaphor.modules"]
"general_ui_components" = "gaphor.diagram.general.uicomponents"
"style_editor" = "gaphor.diagram.styleeditor"
"uml_ui_components" = "gaphor.UML.uicomponents"
"sysml_property_pages" = "gaphor.SysML.uicomponents"
"c4model_property_pages" = "gaphor.C4Model.propertypages"

[project.entry-points."gaphor.services"]
"component_registry" = "gaphor.services.componentregistry:ComponentRegistry"
"event_manager" = "gaphor.core.eventmanager:EventManager"
"properties" = "gaphor.services.properties:Properties"
"undo_manager" = "gaphor.services.undomanager:UndoManager"
"element_factory" = "gaphor.core.modeling:ElementFactory"
"element_dispatcher" = "gaphor.core.modeling.elementdispatcher:ElementDispatcher"
"modeling_language" = "gaphor.services.modelinglanguage:ModelingLanguageService"
"file_manager" = "gaphor.ui.filemanager:FileManager"
"recent_files" = "gaphor.ui.recentfiles:RecentFiles"
"main_window" = "gaphor.ui.mainwindow:MainWindow"
"export_menu" = "gaphor.ui.menufragment:MenuFragment"
"tools_menu" = "gaphor.ui.menufragment:MenuFragment"
"undo_actions" = "gaphor.ui.undoactions:UndoActions"
"sanitizer" = "gaphor.UML.sanitizerservice:SanitizerService"
"recovery" = "gaphor.storage.recovery:Recovery"
"model_browser" = "gaphor.ui.modelbrowser:ModelBrowser"
"toolbox" = "gaphor.ui.toolbox:Toolbox"
"diagrams" = "gaphor.ui.diagrams:Diagrams"
"diagram_align" = "gaphor.ui.diagramalign:DiagramAlign"
"element_editor" = "gaphor.ui.elementeditor:ElementEditor"
"model_changed" = "gaphor.ui.modelchanged:ModelChanged"
"console_window" = "gaphor.plugins.console.consolewindow:ConsoleWindow"
"diagram_export" = "gaphor.plugins.diagramexport.export:DiagramExport"
"auto_layout" = "gaphor.plugins.autolayout:AutoLayoutService"
"html_report" = "gaphor.plugins.htmlreport.report:HtmlReportExport"

[project.entry-points."gaphor.modelinglanguages"]
"Core" = "gaphor.core.modeling.modelinglanguage:CoreModelingLanguage"
"UML" = "gaphor.UML.modelinglanguage:UMLModelingLanguage"
"SysML" = "gaphor.SysML.modelinglanguage:SysMLModelingLanguage"
"C4Model" = "gaphor.C4Model.modelinglanguage:C4ModelLanguage"
"RAAML" = "gaphor.RAAML.modelinglanguage:RAAMLModelingLanguage"
"general" = "gaphor.diagram.general.modelinglanguage:GeneralModelingLanguage"

[project.entry-points."gaphor.argparsers"]
gui = "gaphor.main:gui_parser"
self-test = "gaphor.main:self_test_parser"
exec = "gaphor.main:exec_parser"
export = "gaphor.plugins.diagramexport.exportcli:export_parser"
html-report = "gaphor.plugins.htmlreport.reportcli:html_report_parser"
install-schemas = "gaphor.ui.installschemas:install_schemas_parser"

[project.entry-points."babel.extractors"]
"gaphor" = "gaphor.babel:extract_gaphor"

[tool.poetry]
requires-poetry = ">=2.0"
include = [
    { path = "gaphor/locale/*/LC_MESSAGES/*" },
    { path = "data/org.gaphor.Gaphor*", format = "sdist" },
]
exclude = ["**/tests", "gaphor/conftest.py" ]

# When building these from source, use setuptools<82 (pkg_resources removed in 82)
[tool.poetry.build-constraints]
pyobjc-framework-cocoa = { setuptools = "<82" }
pyobjc-core = { setuptools = "<82" }

[tool.poetry.group.dev.dependencies]
pytest = ">=7.1,<9.1"
pytest-archon = "^0.0"
pytest-cov = ">=4,<8"
pytest-randomly = "^4.0.1"
xdoctest = "^1.3.0"
hypothesis = "^6.151.2"
ipython = "^9.9.0"
sphinx = ">=6,<10"
babelgladeextractor = "^0.7"
pytest-asyncio = "^1.2.0"
markdown-it-py = ">=3.0,<5.0"
pygobject-stubs = "^2.16.0"

[tool.poetry.group.lint.dependencies]
pre-commit = ">=2.20,<5.0"

[tool.poetry.group.automation.dependencies]
poethepoet = "^0.43.0"

[tool.poetry.group.docs]
optional=true

[tool.poetry.group.docs.dependencies]
sphinx = ">=6,<10"
sphinx-copybutton = "^0.5.0"
sphinx-intl = "^2.3.2"
myst-nb = "^1.4.0"
furo = ">=2022,<2026"

[tool.poetry.group.packaging]
optional=true

[tool.poetry.group.packaging.dependencies]
pyinstaller = ">=6.13.0"
pyinstaller-versionfile = "^3.0.1"
semver = ">=2.13,<4.0"
dmgbuild = {version = "^1.6.7", markers = "sys_platform == 'darwin'" }

[tool.poe.tasks]
coremodel.script = """gaphor.codegen.coder:main(
    modelfile='models/Core.gaphor',
    overridesfile='models/Core.override',
    outfile='gaphor/core/modeling/coremodel.py'
    )"""
uml.script = """gaphor.codegen.coder:main(
    modelfile='models/UML.gaphor',
    overridesfile='models/UML.override',
    outfile='gaphor/UML/uml.py',
    supermodelfiles=[('Core', 'models/Core.gaphor')]
    )"""
sysml.script = """gaphor.codegen.coder:main(
    modelfile='models/SysML.gaphor',
    overridesfile='models/SysML.override',
    outfile='gaphor/SysML/sysml.py',
    supermodelfiles=[
        ('UML', 'models/UML.gaphor'),
        ('Core', 'models/Core.gaphor')]
    )"""
raaml.script = """gaphor.codegen.coder:main(
    modelfile='models/RAAML.gaphor',
    outfile='gaphor/RAAML/raaml.py',
    supermodelfiles=[
        ('SysML', 'models/SysML.gaphor'),
        ('UML', 'models/UML.gaphor'),
        ('Core', 'models/Core.gaphor')]
    )"""
c4model.script = """gaphor.codegen.coder:main(
    modelfile='models/C4Model.gaphor',
    outfile='gaphor/C4Model/c4model.py',
    supermodelfiles=[
        ('UML', 'models/UML.gaphor'),
        ('Core', 'models/Core.gaphor')]
    )"""
lint = "pre-commit run --all-files"
docs = { "cwd" = "docs", "shell" = "sphinx-build -W -b html . _build/html" }
docs-gettext-pot = { "cwd" = "docs", "shell" = "sphinx-build -b gettext . locale" }
clean = { "shell" = "rm -rf dist build docs/_build" }
appdata = { "script" = "scripts.update_appdata" }
package = { shell = "pyinstaller -y _packaging/gaphor.spec" }
win-installer = { "script" = "scripts.build_win_installer:main" }
gettext-pot = { "shell" = "pybabel extract -o po/gaphor.pot -F po/babel.ini -k i18nize gaphor" }
gettext-po = { "script" = "scripts.build_babel:update_po_files" }
gettext-mo-all = { "script" = "scripts.build_babel:compile_mo_all" }
gettext-mo-release = { "script" = "scripts.build_babel:compile_mo_release" }
gettext-docs-pot = { "cwd" = "docs", "shell" = "sphinx-build -b gettext . locale" }
gettext-docs-po = { "cwd" = "docs", "shell" = "sphinx-intl update -p locale" }
translations = [ "gettext-pot", "gettext-po", "gettext-mo-all", "gettext-docs-pot", "gettext-docs-po" ]
icons = { "shell" = "make -C gaphor/ui/icons" }

[tool.pytest.ini_options]
testpaths = [
    "gaphor",
    "tests",
    "docs",
]
python_files = "test_*.py"
addopts = [
    "--xdoctest",
    "--import-mode=importlib",
]
junit_family = "xunit1"

[tool.mypy]
python_version = "3.12"
warn_return_any = true
warn_unused_configs = true
warn_redundant_casts = true
check_untyped_defs = true
strict_optional = true
disallow_any_explicit = true
show_error_codes = true
warn_unused_ignores = true
namespace_packages = true

[[tool.mypy.overrides]]
module = [
    "gaphor.core.modeling.coremodel",
    "gaphor.UML.uml",
    "gaphor.SysML.sysml",
]
warn_unused_ignores = false
ignore_errors = true

[[tool.mypy.overrides]]
module = "*.tests.*"
ignore_errors = true

[tool.ruff]
line-length = 88
target-version = "py312"

[tool.ruff.lint]
exclude = [
    ".venv",
    "dist",
    "gaphor/core/modeling/coremodel.py",
    "gaphor/C4Model/c4model.py",
    "gaphor/RAAML/raaml.py",
    "gaphor/SysML/sysml.py",
    "gaphor/UML/uml.py",
]
ignore = ["E501"]
select = [
    "B",
    "B9",
    "C",
    "E",
    "F",
    "PLW1",
    "SLF",
    "T20",
    "UP",
    "W",
]
extend-select = ["I"]

[tool.ruff.lint.mccabe]
max-complexity = 18

[build-system]
requires = ["poetry-core>=2.0.0,<3.0.0"]
build-backend = "poetry.core.masonry.api"

Poetry Runtime Logs

poetry-runtime.log

rtd-command-info] start-time: 2026-04-06T11:22:54.881072Z, end-time: 2026-04-06T11:23:21.660948Z, duration: 26, exit-code: 1
VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install -vv --with docs --no-interaction
Using virtualenv: /home/docs/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240
Checking keyring availability: Unavailable
Installing dependencies from lock file

Finding the necessary packages for the current system

Package operations: 84 installs, 0 updates, 0 removals, 29 skipped

- Installing accessible-pygments (0.0.5)
- Installing alabaster (1.0.0): Skipped for the following reason: Already installed
- Installing attrs (26.1.0)
- Installing asttokens (3.0.1)
- Installing babel (2.18.0): Skipped for the following reason: Already installed
- Installing babelgladeextractor (0.7.2)
- Installing better-exceptions (0.3.3)
- Installing beautifulsoup4 (4.14.3)
- Installing certifi (2026.2.25): Skipped for the following reason: Already installed
- Installing cfgv (3.5.0)
- Installing charset-normalizer (3.4.7): Skipped for the following reason: Already installed
- Installing click (8.3.2)
- Installing comm (0.2.3)
- Installing coverage (7.13.5)
- Installing debugpy (1.8.20)
- Installing decorator (5.2.1)
- Installing defusedxml (0.7.1)
- Installing distlib (0.4.0): Skipped for the following reason: Already installed
- Installing docutils (0.22.4): Skipped for the following reason: Already installed
- Installing dulwich (1.1.0): Skipped for the following reason: Already installed
- Installing executing (2.2.1)
- Installing fastjsonschema (2.21.2): Skipped for the following reason: Already installed
- Installing filelock (3.25.2): Skipped for the following reason: Already installed
- Installing furo (2025.12.19)
- Installing gaphas (5.1.2)
- Installing generic (1.1.7)
- Installing greenlet (3.3.2)
- Installing hypothesis (6.151.11)
- Installing identify (2.6.18)
- Installing idna (3.11): Skipped for the following reason: Already installed
- Installing imagesize (2.0.0): Skipped for the following reason: Already installed
- Installing importlib-metadata (9.0.0)
- Installing iniconfig (2.3.0)
- Installing ipykernel (7.2.0)
- Installing ipython (9.12.0)
- Installing ipython-pygments-lexers (1.1.1)
- Installing jedi (0.19.2)
- Installing jinja2 (3.1.6): Skipped for the following reason: Already installed
- Installing jsonschema (4.26.0)
- Installing jsonschema-specifications (2025.9.1)
- Installing jupyter-cache (1.0.1)
- Installing jupyter-client (8.8.0)
- Installing jupyter-core (5.9.1)
- Installing markdown-it-py (4.0.0)
- Installing markupsafe (3.0.3): Skipped for the following reason: Already installed
- Installing matplotlib-inline (0.2.1)
- Installing mdit-py-plugins (0.5.0)
- Installing mdurl (0.1.2)
- Installing myst-nb (1.4.0)
- Installing myst-parser (5.0.0)
- Installing nbclient (0.10.4)
- Installing nbformat (5.10.4)
- Installing nest-asyncio (1.6.0)
- Installing nodeenv (1.10.0)
- Installing packaging (26.0): Skipped for the following reason: Already installed
- Installing pastel (0.2.1)
- Installing parso (0.8.6)
- Installing pexpect (4.9.0)
- Installing pillow (12.2.0)
- Installing platformdirs (4.9.4): Skipped for the following reason: Already installed
- Installing pluggy (1.6.0)
- Installing poethepoet (0.43.0)
- Installing pre-commit (4.5.1)
- Installing prompt-toolkit (3.0.52)
- Installing psutil (7.2.2)
- Installing ptyprocess (0.7.0)
- Installing pure-eval (0.2.3)
- Installing pycairo (1.29.0)
- Installing pydot (4.0.1)
- Installing pygments (2.20.0): Skipped for the following reason: Already installed
- Installing pygobject (3.56.2)
- Installing pygobject-stubs (2.17.0)
- Installing pyparsing (3.3.2)
[virtualenv:virtualenv.app_data] migrating app data from /home/docs/.local/share/virtualenv to /home/docs/.cache/virtualenv
- Installing pytest (9.0.2)
[python_discovery:python_discovery._discovery] find interpreter for spec PythonSpec(path=/home/docs/.asdf/installs/python/3.14.0/bin/python3.14)
[python_discovery:python_discovery._discovery] find interpreter for spec PythonSpec(path=/home/docs/.asdf/installs/python/3.14.0/bin/python3.14)
- Installing pytest-archon (0.0.7)
- Installing pytest-asyncio (1.3.0)
[python_discovery:python_discovery._discovery] find interpreter for spec PythonSpec(path=/home/docs/.asdf/installs/python/3.14.0/bin/python3.14)
[python_discovery:python_discovery._discovery] proposed PythonInfo(spec=CPython3.14.0.final.0-64-x86_64, exe=/home/docs/.asdf/installs/python/3.14.0/bin/python3.14, platform=linux, version='3.14.0 (main, Mar 19 2026, 17:06:41) [GCC 13.2.0]', encoding_fs_io=utf-8-utf-8)
[python_discovery:python_discovery._discovery] proposed PythonInfo(spec=CPython3.14.0.final.0-64-x86_64, exe=/home/docs/.asdf/installs/python/3.14.0/bin/python3.14, platform=linux, version='3.14.0 (main, Mar 19 2026, 17:06:41) [GCC 13.2.0]', encoding_fs_io=utf-8-utf-8)
[python_discovery:python_discovery._discovery] proposed PythonInfo(spec=CPython3.14.0.final.0-64-x86_64, exe=/home/docs/.asdf/installs/python/3.14.0/bin/python3.14, platform=linux, version='3.14.0 (main, Mar 19 2026, 17:06:41) [GCC 13.2.0]', encoding_fs_io=utf-8-utf-8)
- Installing pytest-cov (7.1.0)
- Installing pytest-randomly (4.0.1)
[virtualenv:virtualenv.seed.embed.base_embed] The --no-wheel and --wheel options are deprecated. They have no effect for Python > 3.8 as wheel is no longer bundled in virtualenv.
[virtualenv:virtualenv.seed.embed.base_embed] The --no-wheel and --wheel options are deprecated. They have no effect for Python > 3.8 as wheel is no longer bundled in virtualenv.
[virtualenv:virtualenv.run.session] create virtual environment via CPython3Posix(dest=/tmp/tmplopyrcxm/.venv, clear=False, no_vcs_ignore=False, global=False)
[virtualenv:virtualenv.run.session] create virtual environment via CPython3Posix(dest=/tmp/tmpuut7nc30/.venv, clear=False, no_vcs_ignore=False, global=False)
[virtualenv:virtualenv.run.session] add activators for Bash, CShell, Fish, Nushell, PowerShell, Python
[virtualenv:virtualenv.run.session] add activators for Bash, CShell, Fish, Nushell, PowerShell, Python

Stack trace:

36  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/executor.py:297 in _execute_operation
      result = self._do_execute_operation(operation)

35  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/executor.py:431 in _do_execute_operation
      result: int = getattr(self, f"_execute_{method}")(operation)

34  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/executor.py:555 in _execute_install
      status_code = self._install(operation)

33  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/executor.py:591 in _install
      archive = self._download(operation)

32  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/executor.py:735 in _download
      return self._download_link(operation, link)

31  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/executor.py:771 in _download_link
      archive = self._chef.prepare(

30  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/chef.py:58 in prepare
      return self._prepare_sdist(

29  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/chef.py:122 in _prepare_sdist
      return self._prepare(

28  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/installation/chef.py:75 in _prepare
      with isolated_builder(

27  ~/.asdf/installs/python/3.14.0/lib/python3.14/contextlib.py:141 in __enter__
      return next(self.gen)

26  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/utils/isolated_build.py:206 in isolated_builder
      with ephemeral_environment(

25  ~/.asdf/installs/python/3.14.0/lib/python3.14/contextlib.py:141 in __enter__
      return next(self.gen)

24  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/utils/env/__init__.py:43 in ephemeral_environment
      EnvManager.build_venv(

23  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/poetry/utils/env/env_manager.py:561 in build_venv
      cli_result = virtualenv.cli_run(args, setup_logging=False)

22  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/virtualenv/run/__init__.py:44 in cli_run
      of_session = session_via_cli(args, options, setup_logging, env)

21  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/virtualenv/run/__init__.py:68 in session_via_cli
      parser, elements = build_parser(args, options, setup_logging, env)

20  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/virtualenv/run/__init__.py:112 in build_parser
      ActivationSelector(interpreter, parser),

19  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/virtualenv/run/plugin/activators.py:23 in __init__
      for k, v in self.options("virtualenv.activate").items()

18  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/virtualenv/run/plugin/base.py:49 in options
      cls._OPTIONS = cls.entry_points_for(key)

17  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/virtualenv/run/plugin/base.py:25 in entry_points_for
      return OrderedDict((e.name, e.load()) for e in cls.entry_points().select(group=key))  # ty: ignore[unresolved-attribute]

16  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/virtualenv/run/plugin/base.py:25 in <genexpr>
      return OrderedDict((e.name, e.load()) for e in cls.entry_points().select(group=key))  # ty: ignore[unresolved-attribute]

15  ~/.asdf/installs/python/3.14.0/lib/python3.14/importlib/metadata/__init__.py:179 in load
      module = import_module(match.group('module'))

14  ~/.asdf/installs/python/3.14.0/lib/python3.14/importlib/__init__.py:88 in import_module
      return _bootstrap._gcd_import(name[level:], package, level)

13  <frozen importlib._bootstrap>:1398 in _gcd_import
      

12  <frozen importlib._bootstrap>:1371 in _find_and_load
      

11  <frozen importlib._bootstrap>:1314 in _find_and_load_unlocked
      

10  <frozen importlib._bootstrap>:491 in _call_with_frames_removed
      

 9  <frozen importlib._bootstrap>:1398 in _gcd_import
      

 8  <frozen importlib._bootstrap>:1371 in _find_and_load
      

 7  <frozen importlib._bootstrap>:1342 in _find_and_load_unlocked
      

 6  <frozen importlib._bootstrap>:938 in _load_unlocked
      

 5  <frozen importlib._bootstrap_external>:762 in exec_module
      

 4  <frozen importlib._bootstrap>:491 in _call_with_frames_removed
      

 3  ~/checkouts/readthedocs.org/user_builds/gaphor-es/envs/4240/lib/python3.14/site-packages/virtualenv/activation/__init__.py:8 in <module>
      from .powershell import PowerShellActivator

 2  <frozen importlib._bootstrap>:1368 in _find_and_load
      

 1  <frozen importlib._bootstrap>:421 in __enter__
      

_DeadlockError

deadlock detected by _ModuleLock('virtualenv.activation.powershell') at 129806433602256

at <frozen importlib._bootstrap>:346 in acquire

Cannot install pygobject-stubs.

- Installing python-dateutil (2.9.0.post0)
- Installing python-discovery (1.2.1): Skipped for the following reason: Already installed
- Installing pyzmq (27.1.0)
- Installing pyyaml (6.0.3)
- Installing referencing (0.37.0)
- Installing requests (2.33.1): Skipped for the following reason: Already installed
- Installing roman-numerals (4.1.0): Skipped for the following reason: Already installed
- Installing rpds-py (0.30.0)
- Installing six (1.17.0)
- Installing snowballstemmer (3.0.1): Skipped for the following reason: Already installed
- Installing soupsieve (2.8.3)
- Installing sortedcontainers (2.4.0)
- Installing sphinx (9.1.0): Skipped for the following reason: Already installed
- Installing sphinx-basic-ng (1.0.0b2)
- Installing sphinx-copybutton (0.5.2)
- Installing sphinx-intl (2.3.2)
- Installing sphinxcontrib-applehelp (2.0.0): Skipped for the following reason: Already installed
- Installing sphinxcontrib-devhelp (2.0.0): Skipped for the following reason: Already installed
- Installing sphinxcontrib-htmlhelp (2.1.0): Skipped for the following reason: Already installed
- Installing sphinxcontrib-jsmath (1.0.1): Skipped for the following reason: Already installed
- Installing sphinxcontrib-qthelp (2.0.0): Skipped for the following reason: Already installed
- Installing sphinxcontrib-serializinghtml (2.0.0): Skipped for the following reason: Already installed
- Installing sqlalchemy (2.0.49)
- Installing stack-data (0.6.3)
- Installing tabulate (0.10.0)
- Installing tinycss2 (1.5.1)
- Installing tornado (6.5.5)
- Installing traitlets (5.14.3)
- Installing typing-extensions (4.15.0)
- Installing urllib3 (2.6.3): Skipped for the following reason: Already installed
- Installing virtualenv (21.2.0): Skipped for the following reason: Already installed
- Installing wcwidth (0.6.0)
- Installing webencodings (0.5.1)
- Installing xdoctest (1.3.2)
- Installing zipp (3.23.0)
[build:build] Getting build dependencies for wheel...
[python_discovery:python_discovery._discovery] find interpreter for spec PythonSpec(path=/home/docs/.asdf/installs/python/3.14.0/bin/python3.14)
[python_discovery:python_discovery._discovery] proposed PythonInfo(spec=CPython3.14.0.final.0-64-x86_64, exe=/home/docs/.asdf/installs/python/3.14.0/bin/python3.14, platform=linux, version='3.14.0 (main, Mar 19 2026, 17:06:41) [GCC 13.2.0]', encoding_fs_io=utf-8-utf-8)
[virtualenv:virtualenv.seed.embed.base_embed] The --no-wheel and --wheel options are deprecated. They have no effect for Python > 3.8 as wheel is no longer bundled in virtualenv.
[virtualenv:virtualenv.run.session] create virtual environment via CPython3Posix(dest=/tmp/tmpan4z1wne/.venv, clear=False, no_vcs_ignore=False, global=False)
[virtualenv:virtualenv.run.session] add activators for Bash, CShell, Fish, Nushell, PowerShell, Python
[build:build] Getting build dependencies for wheel...
[build:build] Building wheel...
[build:build] Building wheel...
[build:build] Getting build dependencies for wheel...
[build:build] Building wheel...

[dimbleby]

Seems likely you should raise this with virtualenv

[radoering]

Since this error started happening over the last few months, I could also try to isolate the error to a specific Poetry version.

Since the traceback points to virtualenv, you may also want to try to isolate the virtualenv version:

• Poetry changelog with release dates: https://python-poetry.org/history/
• virtualenv changelog with release dates: https://virtualenv.pypa.io/en/latest/changelog.html

[danyeaw]

I'm still attempting to narrow this down to either a virtualenv issue or poetry issue. Here is the latest build error when trying to build a wheel from a sdist:

[build:build] Building wheel...
[build:build] Getting build dependencies for wheel...
  Stack trace:
  8  ~/checkouts/readthedocs.org/user_builds/gaphor-fr/envs/4244/lib/python3.14/site-packages/poetry/installation/executor.py:297 in _execute_operation
      295│ 
      296│             try:
    → 297│                 result = self._do_execute_operation(operation)
      298│             except EnvCommandError as e:
      299│                 if e.e.returncode == -2:
  7  ~/checkouts/readthedocs.org/user_builds/gaphor-fr/envs/4244/lib/python3.14/site-packages/poetry/installation/executor.py:431 in _do_execute_operation
      429│             return 0
      430│ 
    → 431│         result: int = getattr(self, f"_execute_{method}")(operation)
      432│ 
      433│         if result != 0:
  6  ~/checkouts/readthedocs.org/user_builds/gaphor-fr/envs/4244/lib/python3.14/site-packages/poetry/installation/executor.py:555 in _execute_install
      553│ 
      554│     def _execute_install(self, operation: Install | Update) -> int:
    → 555│         status_code = self._install(operation)
      556│ 
      557│         self._save_url_reference(operation)
  5  ~/checkouts/readthedocs.org/user_builds/gaphor-fr/envs/4244/lib/python3.14/site-packages/poetry/installation/executor.py:608 in _install
      606│                 self._remove(operation.initial_package)
      607│ 
    → 608│             self._wheel_installer.install(archive)
      609│         finally:
      610│             if cleanup_archive:
  4  ~/checkouts/readthedocs.org/user_builds/gaphor-fr/envs/4244/lib/python3.14/site-packages/poetry/installation/wheel_installer.py:103 in install
      101│ 
      102│     def install(self, wheel: Path) -> None:
    → 103│         with WheelFile.open(wheel) as source:
      104│             try:
      105│                 # Content validation is temporarily disabled because of
  3  ~/.asdf/installs/python/3.14.0/lib/python3.14/contextlib.py:141 in __enter__
      139│         del self.args, self.kwds, self.func
      140│         try:
    → 141│             return next(self.gen)
      142│         except StopIteration:
      143│             raise RuntimeError("generator didn't yield") from None
  2  ~/checkouts/readthedocs.org/user_builds/gaphor-fr/envs/4244/lib/python3.14/site-packages/installer/sources.py:162 in open
      160│     def open(cls, path: "os.PathLike[str]") -> Iterator["WheelFile"]:
      161│         """Create a wheelfile from a given path."""
    → 162│         with zipfile.ZipFile(path) as f:
      163│             yield cls(f)
      164│ 
  1  ~/.asdf/installs/python/3.14.0/lib/python3.14/zipfile/__init__.py:1458 in __init__
      1456│         try:
      1457│             if mode == 'r':
    → 1458│                 self._RealGetContents()
      1459│             elif mode in ('w', 'x'):
      1460│                 # set the modified flag so central directory gets written
  BadZipFile
  File is not a zip file
  at ~/.asdf/installs/python/3.14.0/lib/python3.14/zipfile/__init__.py:1525 in _RealGetContents
      1521│             endrec = _EndRecData(fp)
      1522│         except OSError:
      1523│             raise BadZipFile("File is not a zip file")
      1524│         if not endrec:
    → 1525│             raise BadZipFile("File is not a zip file")
      1526│         if self.debug > 1:
      1527│             print(endrec)
      1528│         self._comment = endrec[_ECD_COMMENT]    # archive comment
      1529│ 
Cannot install pycairo.