Coverage.py: Which python binary is used?

Python Help
1

I am in the middle of debugging a problem with my CI.

I wonder how “coverage” (ping @nedbat) do determine which python interpreter binary it uses. I couldn’t find that info in the docs or in the debug output.

2

I’ve never given it much thought, but I suspect it uses the Python executable running pip when you installed it.

3

It will depend on how you installed coverage.

Did you use a OS package manager? Did you use pip?

You can look at the shebang line in the coverage file and check what it uses.

If on fedora I install python3-coverage I see that the shebang line is:

#!/usr/bin/python3
# EASY-INSTALL-ENTRY-SCRIPT: 'coverage==7.2.7','console_scripts','coverage-3.12'
import re

The other way to be sure which python version is being used to to run coverage via -m which will also when from a venv.

$ python3.12 -m coverage
Code coverage for Python, version 7.2.7 with C extension.  Use 'coverage help' for help.
Full documentation is at https://coverage.readthedocs.io/en/7.2.7
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4

The two previous replies are spot on.

The coverage debug output will show it, though there are lots of different kinds of coverage debug output. The executable line shows which Python interpreter is being used:

% coverage debug sys
-- sys -------------------------------------------------------
               coverage_version: 7.4.1
                coverage_module: /usr/local/virtualenvs/tmp-6ac9a881e8c3ac0/lib/python3.11/site-packages/coverage/__init__.py
                           core: -none-
                        CTracer: available
           plugins.file_tracers: -none-
            plugins.configurers: -none-
      plugins.context_switchers: -none-
              configs_attempted: .coveragerc
                                 setup.cfg
                                 tox.ini
                                 pyproject.toml
                   configs_read: -none-
                    config_file: None
                config_contents: -none-
                      data_file: -none-
                         python: 3.11.7 (main, Jan 20 2024, 07:01:12) [Clang 15.0.0 (clang-1500.1.0.2.5)]
                       platform: macOS-14.2.1-arm64-arm-64bit
                 implementation: CPython
                     executable: /usr/local/virtualenvs/tmp-6ac9a881e8c3ac0/bin/python
                   def_encoding: utf-8
                    fs_encoding: utf-8
                            pid: 99930
                            cwd: /usr/local/virtualenvs/tmp-6ac9a881e8c3ac0
                           path: /usr/local/virtualenvs/tmp-6ac9a881e8c3ac0/bin
                                 /usr/local/pyenv/pyenv/versions/3.11.7/lib/python311.zip
                                 /usr/local/pyenv/pyenv/versions/3.11.7/lib/python3.11
                                 /usr/local/pyenv/pyenv/versions/3.11.7/lib/python3.11/lib-dynload
                                 /usr/local/virtualenvs/tmp-6ac9a881e8c3ac0/lib/python3.11/site-packages
                    environment: HOME = /Users/ned
                                 PYTHONPYCACHEPREFIX = /tmp/ned-pyc
                                 PYTHONSTARTUP = /Users/ned/.config/startup.py
                                 VIRTUALENVWRAPPER_PYTHON = /usr/local/pyenv/pyenv/versions/3.11.7/bin/python3.11
                   command_line: /usr/local/virtualenvs/tmp-6ac9a881e8c3ac0/bin/coverage debug sys
(etc...)
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