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  1. Qt
  2. QTBUG-96291

Import QtQuick.VirtualKeyboard breaks QML app with weird errors if QT_IM_MODULE is not set to qtvirtualkeyboard



    • Type: Bug
    • Status: Reported
    • Priority: P2: Important
    • Resolution: Unresolved
    • Affects Version/s: 5.15.2
    • Fix Version/s: None
    • Component/s: Virtual Keyboard
    • Labels:



      Importing VirtualKeyboard module breaks the import if Qt application is not set to use the VirtualKeyboard as input method module (QT_IM_MODULE environment variable). It's hard to specify what should really happen in such case, but one thing for sure: the current error message is very misleading and inappropriate.

      In my case, I had my custom InputPanel singleton type in a directory with qmldir. My project has two build artifacts: main app (which uses virtual keyboard) and a playground (which doesn't). Now, attempt to import and use other, even non-singleton, types from that module/directory fails in a playground, because QT_IM_MODULE is not enabled. As a workaround, I moved that custom InputPanel into a separate directory which only ever gets imported from relevant pages of the main app, and never from the playground.

      Steps to reproduce

      1. Create a template QtQuick app (check "use virtual keyboard" option on your way).
      2. Comment out qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard")); or anything like that in main.cpp.
      3. Create a module with a singleton component of InputPanel type, which obviously uses import QtQuick.VirtualKeyboard 2.15 import.
      3. From main.qml import the module created in step 3.
      4. Build & Run.

      Expected result

      Either one or a combination of:

      • Warning message to stderr
      • Fatal error to stdout and exit
      • Silently skip an import and pretend nothing happened (pretty shady)
      • Provide stub types

      Actual result

      QQmlApplicationEngine failed to load component
      qrc:/main.qml:19:5: Type InputPanel unavailable
      qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml:127:5: Type Keyboard unavailable
      qrc:/QtQuick/VirtualKeyboard/content/components/Keyboard.qml:38:1: module "QtQuick.VirtualKeyboard.Plugins" is not installed

      This error message is pretty far from what's actually going on, and is very confusing. It makes people file irrelevant bug reports like this: https://github.com/sddm/sddm/issues/1290 — can't really blame them: they have everything installed, but their software mysteriously doesn't work.


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            jakoivik Jarkko Koivikko
            ratijas ivan tkachenko
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