Topic: deprecate offline parameter validation and "combinations.json"

[pzhlkj6612]

Is your feature request related to a problem? Please describe.

Let's say goodbye to our old friend "Specified Qt version is unknown" and their partners. They always confuse our users.

$ aqt install-qt linux desktop 9.9.9
INFO    : aqtinstall(aqt) v3.1.11 on Python 3.10.12 [CPython GCC 11.4.0]
WARNING : Specified Qt version "9.9.9" did not exist when this version of aqtinstall was released. This may not install properly, but we will try our best.
WARNING : Failed to download checksum for the file 'Updates.xml'. This may happen on unofficial mirrors.
ERROR   : Failed to locate XML data for Qt version '9.9.9'.
==============================Suggested follow-up:==============================
* Please use 'aqt list-qt linux desktop' to show versions available.

$ aqt install-qt linux desktop 9.9.9
INFO    : aqtinstall(aqt) v2.2.4 on Python 3.10.12 [CPython GCC 11.4.0]
WARNING : Specified Qt version is unknown: 9.9.9.
ERROR   : Failed to locate XML data for Qt version '9.9.9'.
==============================Suggested follow-up:==============================
* Please use 'aqt list-qt linux desktop' to show versions available.

$ aqt install 9.9.9 linux desktop
aqtinstall(aqt) v1.2.5 on Python 3.10.12 [CPython GCC 11.4.0]
Specified Qt version is unknown: 9.9.9.
Download error when access to https://download.qt.io/online/qtsdkrepository/linux_x64/desktop/qt9_999/Updates.xml
Server response code: 404, reason: Not Found

Describe the solution you'd like

$ aqt install 9.9.9 linux desktop
aqtinstall(aqt) v...
WARNING : Failed to download checksum for the file 'Updates.xml'. This may happen on unofficial mirrors.
ERROR   : Failed to locate XML data for Qt version '9.9.9'.
============================================================
Available Qt versions: 5.15.2, 6.0.4...

Describe alternatives you've considered

None.

Additional context

From What's the purpose of making the "combinations.json" file? · miurahr/aqtinstall · Discussion #747.