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Python Launcher ignoring config files #95359

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Python Launcher ignoring config files#95359
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zooba
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3.11only security fixesOS-windowsrelease-blockertype-bugAn unexpected behavior, bug, or error

Description

@SteveBarnes-BH
SteveBarnes-BH
opened on Jul 28, 2022

Bug report

Following installing 3.11.0b5 (main, Jul 25 2022, 22:59:14) [MSC v.1932 64 bit (AMD64)] with install launcher for all users py-0 reports that 3.11 is the default py target. Adding a py.ini file with the contents below to both of the following locations:

  1. C:\Windows
  2. %APPDATA%
    Does not override this - settung PY_PYTHON=3.9 does.
    File content:
[defaults]
python=3.9

Running the older launcher the .ini file settings are honored i.e. py -0 reports 3.9 as the default.

Your environment

Windows 10 - 64bit

  • CPython versions tested on:
  • Operating system and architecture:
    Windows 10 - 64bit Python: 3.11.0b5 (main, Jul 25 2022, 22:59:14) [MSC v.1932 64 bit (AMD64)] but with multiple other pythons installed.

Activity

  1. SteveBarnes-BH
    added
    type-bugAn unexpected behavior, bug, or error
    on Jul 28, 2022

  2. eryksun commented on Jul 28, 2022

    @eryksun
    eryksun
    on Jul 28, 2022
    Contributor

    The ini file is searched for as "%LOCALAPPDATA%\py.ini" and "%__APPDIR__%\py.ini" (i.e. beside "py.exe")1. "%APPDATA%\py.ini" has never been checked.

    Checking the docs, I see that the "defaults" section is documented to use value names that are "the same as the environment variables without the leading PY_ prefix". There's no "py_" prefix used in the ini file because it configures the default "python", "python3", and "python2" commands, just as in in the "commands" section. This matches the behavior of the old launcher's get_configured_value() function.

    The new launcher's checkDefaults() function is designed to use the same names as the environment variables, with the "py_" prefix. This is inconsistent with the old launcher and conceptually inconsistent. It should skip past the "py_" prefix (e.g. &settingName[3]) when calling _readIni().

    Footnotes

    1. I think the search should be extended to check "%LOCALAPPDATA%\Python\py.ini", "%LOCALAPPDATA%\py.ini", "%ProgramData%\Python\py.ini", and "%__APPDIR__%\py.ini". I dislike using the base %LOCALAPPDATA% directory. Applications are supposed to use a subdirectory named for at least the application, if not nested under the organization name. ↩

  3. eryksun
    added
    OS-windows
    3.11only security fixes
    on Jul 28, 2022
  4. eryksun
    assigned
    zooba
    on Jul 28, 2022

  5. SteveBarnes-BH commented on Jul 28, 2022

    @SteveBarnes-BH
    SteveBarnes-BH
    on Jul 28, 2022
    Author

    On checking I already had a %LOCALAPPDATA%\py.ini file and it seem to be ignored:

    $ type %localappdata%\py.ini
[defaults]
python=3.9
python3=3.9

C:\Users\me\AppData\Roaming
$ py -0p
 -V:3.11 *        C:\Python311\python.exe
 -V:3.10          C:\Python310\python.exe
 -V:3.10-32       C:\Python310-32\python.exe
 -V:3.9           C:\Python39\python.exe
 -V:3.9-32        C:\Python39-32\python.exe
 -V:3.8           C:\Python38\python.exe
 -V:3.8-32        C:\Python38-32\python.exe

C:\Users\me\AppData\Roaming
$ py --version
Python 3.11.0b5

    I did find that if I change that specific file to include the prefix:

    [defaults]
py_python=3.9
py_python3=3.9

    The py stops working altogether - no output from py -0 and no python prompt from py so the file is having some impact. 💩 I also tried both variants with all uppercase for the with no difference of behavior.

  6. eryksun commented on Jul 28, 2022

    @eryksun
    eryksun
    on Jul 28, 2022
    Contributor

    The new launcher's _readIni() function mistakenly returns true (i.e. 1) instead of the string length when the ini file is in the local appdata directory. This in turn causes the wcscpy_s(tag, n + 1, buffer) call in checkDefaults() to invoke the invalid parameter handler, which terminates the process.

    When the ini file is beside the launcher instead of in the local appdata directory, _readIni() correctly returns the string length. In this case, py_python=3.9 works for me. Of course, the ini file should instead support python=3.9, which is the initial bug reported here.

  7. SteveBarnes-BH commented on Jul 28, 2022

    @SteveBarnes-BH
    SteveBarnes-BH
    on Jul 28, 2022
    Author

    I can verify that if C:\Windows\py.ini is present and contains the values with prefix it is honored - as long at there isn't also a %LOCALAPPDATA%\py.ini also with the prefixed values - in which case nothing is run.

  8. zooba
    added
    release-blocker
    needs backport to 3.11only security fixes
    on Jul 28, 2022
  9. ezio-melotti
    added this to Release and Deferred blockers 🚫on Jul 28, 2022
  10. ezio-melotti
    moved this to Todo in Release and Deferred blockers 🚫on Jul 28, 2022
  11. zooba
    added a commit that references this issue on Jul 28, 2022

    pythongh-95359: Fix py.exe launcher handling of per-user py.ini and c…

    6414c2d

  12. zooba commented on Jul 28, 2022

    @zooba
    zooba
    on Jul 28, 2022
    Member

    I think the search should be extended to check "%LOCALAPPDATA%\Python\py.ini", "%LOCALAPPDATA%\py.ini", "%ProgramData%\Python\py.ini", and "%__APPDIR__%\py.ini". I dislike using the base %LOCALAPPDATA% directory. Applications are supposed to use a subdirectory named for at least the application, if not nested under the organization name.

    I agree, but am filing it under "let's not cause churn right now" as I've discussed elsewhere.

    The other two issues are easily fixed. Thanks for catching them!

  13. miss-islington
    added a commit that references this issue on Jul 28, 2022

    pythongh-95359: Fix py.exe launcher handling of per-user py.ini and c…

    4d8ae01
  14. zooba
    added a commit that references this issue on Jul 28, 2022

    gh-95359: Fix py.exe launcher handling of per-user py.ini and command…

    38bb206
  15. miss-islington
    added a commit that references this issue on Jul 28, 2022

    gh-95359: Fix py.exe launcher handling of per-user py.ini and command…

    1368a1f

  16. SteveBarnes-BH commented on Jul 29, 2022

    @SteveBarnes-BH
    SteveBarnes-BH
    on Jul 29, 2022
    Author

    Proves the value of the beta testing - catches issues that occur in non-isolated environments.

  17. zooba
    closed this as completedon Jul 29, 2022
  18. Repository owner moved this from Todo to Done in Release and Deferred blockers 🚫on Jul 29, 2022
  19. picnixz
    removed
    needs backport to 3.11only security fixes
    on Feb 17, 2025
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