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  1. Qt
  2. QTBUG-13849 QML versioning support
  3. QTBUG-13451

Support property versioning in QML

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Details

    • 6c77950e991d8152a9f1221e57c68c6d48dbfc7f

    Description

      Overview

      We have an immediate need to introduce new properties to existing QML items (QTBUG-13512, QTBUG-7300). We want to ensure that these properties are only available if the correct import is used.

      The following should fail:

      import Qt 4.7

Item {
    newPropertyFor48: "myValue"
}

      while the following should succeed

      import Qt 4.8

Item {
    newPropertyFor48: "myValue"
}

      We also need versioning for other things exposed to QML – signals, slots, and Q_INVOKABLEs.

      Reasoning

      QML is slightly different to C++. In C++ adding a new method or property cannot break old applications, whereas in QML as an object's properties can appear in a scope chain it can change what a name resolves to.

      For example, consider these two QML files

      main.qml
=======
import Qt 4.7
Item {
    id: root
    MyComponent {}
}

      MyComponent.qml
==============
import MyModule 1.0
CppItem {
    value: root.x
}

      where CppItem maps to the C++ class QCppItem. If, in a new version of their module, the author of QCppItem adds a "root" property to QCppItem it will break my program. Our solution is to allow the author of QCppItem to say that the new root property is in revision 2 of QCppItem and QML will make sure that it is only accessible if you "import MyModule 1.1". In this way we can permit new properties and features to be added to existing QML elements while not breaking existing programs.

      Who needs it

      This is important for QML itself. QML is currently tied to Qt releases via the import Qt 4.7 module. In order to allow progress in the QML core elements we must decouple the QML elements from minor Qt releases. This allows us to react to stakeholder requirements and address our oversights in a reasonable timeframe. Once the enablers are in place, the QML core elements should have their own module name. The current proposal is to use import QtQuick 1.0 starting with Qt 4.7.1. Note that import Qt 4.7 will continue to work.

      This will also be needed for other modules such as Qt Components and Qt Mobility. Since these are based on Qt 4.7 we must ensure that this is available in Qt 4.7.1.

      Attachments

        Issue Links

          is required for

          Sub-task - The sub-task of the issue QTBUG-15878 Add mirror property to Image, BorderImage and AnimatedImage elements

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-13087 Should be able to delay binding evaluation for dynamically created objects

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-13512 WebView has no way of jumping to an anchor

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-14957 Only core QML elements can have implicit size

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Task - A task that needs to be done. QTBUG-7300 Improve image caching

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Task - A task that needs to be done. QTBUG-15279 Add versioning to new properties in QtQuick 1.1

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Task - A task that needs to be done. QTBUG-15148 Enable setting resize origin for zooming

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Task - A task that needs to be done. QTBUG-16059 Implement deselect() function for TextInput and TextEdit elements

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Suggestion - Public suggestions QTBUG-12306 Add Item.nextSibling and Item.previousSibling properties

          • P4: Low - Would be nice to fix, but it's not very important.
          • Open

          Suggestion - Public suggestions QTBUG-15149 QML Transition element should have "enabled" property

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed

          Suggestion - Public suggestions QTBUG-14296 QML - add support for Text leading (line-spacing)

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Suggestion - Public suggestions QTBUG-11042 Add right-to-left locale support to QtQuick elements

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Suggestion - Public suggestions QTBUG-13351 Qml Viewer runtime.activeWindow functionality should be available for standalone QML applications

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Suggestion - Public suggestions QTBUG-14900 very hard to reload QML Image

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Suggestion - Public suggestions QTBUG-15161 No way of identifying elements created by Repeater

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Suggestion - Public suggestions QTBUG-9712 Image and Text "sizeHints" are hidden in QML components

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Suggestion - Public suggestions QTBUG-11876 Provide row and col spacing properties in Grid object

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Suggestion - Public suggestions QTBUG-12305 TextEdit and Text elements lack visibleLines and maximumVisibleLines properties

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Suggestion - Public suggestions QTBUG-12704 Suggestion to add a reload function to to qml Image

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Suggestion - Public suggestions QTBUG-13242 Support for justification in Text element

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Suggestion - Public suggestions QTBUG-14488 Transition enabled property

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed
          relates to

          Task - A task that needs to be done. QTBUG-13799 Change QML core module to QtQuick 1.0

          • P0: Blocker - MUST be fixed ASAP. This includes issues that prevent/block further Qt development; Legal issues & Serious data loss issues.
          • Closed
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          Activity

            People

              aakenned Aaron Kennedy
              brasser Michael Brasser (closed Nokia identity) (Inactive)
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              8 Vote for this issue
              Watchers:
              12 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved:

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