Bug 231369 – [WPE] QtWPE API has undeclared dependency on qpa/qplatformnativeinterface.h

• Component: WPE WebKit
• Status: NEW

[Michael Catanzaro]

I've failed to figure out how to build the QtWPE API:

/home/mcatanzaro/Projects/WebKit/Source/WebKit/UIProcess/API/wpe/qt/WPEQtView.cpp:33:10: fatal error: qpa/qplatformnativeinterface.h: No such file or directory
   33 | #include <qpa/qplatformnativeinterface.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

Not sure which Qt devel package on Fedora provides this. It appears to be a private header that's not part of the public API?

Anyway, there is a WebKit bug here: OptionsWPE.cmake should detect all requirements and fail during the cmake stage if something is missing, rather than waiting until later to fail during compilation. Currently OptionsWPE.cmake does this:

if (ENABLE_WPE_QT_API)
    find_package(Qt5 REQUIRED COMPONENTS Core Quick Gui)
    find_package(Qt5Test REQUIRED)
endif ()

Something must be missing from here. Not sure what.

[Diego Pino]

In Debian/Ubuntu, qplatformnativeinterface.h is provided by qtbase5-private-dev

```
$ apt-file search qplatformnativeinterface.h
qtbase5-private-dev: /usr/include/x86_64-linux-gnu/qt5/QtGui/5.15.2/QtGui/qpa/qplatformnativeinterface.h
```

In Fedora, the header is provided by the same package but the location it seems to be different:

/usr/include/qt5/QtGui/5.15.1/QtGui/qpa/qplatformnativeinterface.h

https://fedora.pkgs.org/33/fedora-x86_64/qt5-qtbase-private-devel-5.15.1-5.fc33.x86_64.rpm.html

I think there's nothing wrong with the required components in OptionsWPE.cmake as this file seems to be provided by Qt5Gui in both cases.

I think the problem may lay in ${Qt5Gui_PRIVATE_INCLUDE_DIRS} (https://webkit-search.igalia.com/webkit/source/Source/WebKit/PlatformWPE.cmake#456). Perhaps it's not pointing to the right location of the headers in the case of Fedora?

[Michael Catanzaro]

(In reply to Diego Pino from comment #1)
> I think there's nothing wrong with the required components in
> OptionsWPE.cmake as this file seems to be provided by Qt5Gui in both cases.

I don't agree, it's not checking for qt5-qtbase-private-devel at all. Proof: if I install qt5-qtbase-gui-devel but not qt5-qtbase-private-devel, the cmake stage succeeds even though the required package is not installed. So the cmake checks are insufficient.

[Adrian Perez]

I suppose this is not an issue anymore with the Qt6 bindings? We have removed the Qt5 ones (see #305602), and for the Qt6 ones, we have an additional:

  target_link_libraries(qtwpe PRIVATE Qt::QuickPrivate)

We did not have something like that for the Qt5 code, and now the Qt6 one is using imported targets in CMake, and I expect the imported targets pull-in all needed flags for dependencies correctly.