'Unknown module(s)' error building Qt project (with subprojects) in Yocto

[Dane 0]

I am trying to write a Yocto recipe for qthttpserver (https://github.com/qt-labs/qthttpserver, 5.15 branch). Here's what I have so far ('qthttpserver_5.15.bb'):

SUMMARY = "qthttpserver recipe"

DEPENDS = "qtbase qtwebsockets"

LICENSE = "GPL-3.0-only"
LIC_FILES_CHKSUM = "file://LICENSE.GPL3;md5=d32239bcb673463ab874e80d47fae504"

SRC_URI = "gitsm://github.com/qt-labs/qthttpserver.git;protocol=https;branch=5.15"
SRCREV = "52bce52413763ead7759f8c2e374a40bb82f058f"

S = "${WORKDIR}/git"

inherit qmake5

do_install() {
    install -d ${libdir}
    cp ${S}/lib/* ${libdir}/
}

FILES:${PN} += " \
    ${libdir}/* \
"

This fails with Project ERROR: Unknown module(s) in QT: sslserver (presumably because the sslserver subproject is not getting built first?).

If I try to manually run the build from a terminal (in the 'build' directory) with

../recipe-sysroot-native/usr/bin/qmake ../git/qthttpserver.pro -spec linux-g++
../recipe-sysroot-native/usr/bin/make -f Makefile qmake_all

then I get Project ERROR: Unknown module(s) in QT: gui. The 'gui' module is not referenced in the project anywhere that I can find.

If I try to manually run the build (from a terminal, in the 'build' directory) with the 'system' qmake

"/opt/Qt/5.15.2/gcc_64/bin/qmake" ../git/qthttpserver.pro -spec linux-g++
../recipe-sysroot-native/usr/bin/make -f Makefile qmake_all

then it builds fine.

What is going on here?

[Dane 0]

Solved by adding require ../../../meta-qt5/recipes-qt/qt5/qt5.inc to the recipe (and removing inherit qmake5, as it's included in qt5.inc in any case).

Made some progress by setting OE_QMAKE_RECURSIVE = "" but then was struggling with the installation part, and eventually realised that just requiring qt5.inc solved everything.

[jsulm]

@Dane-0 Shouldn't you add sslserver to DEPENDS?

[Dane 0]

@jsulm sslserver is one of the subprojects. Adding it to DEPENDS just errors out, presumably because it hasn't been built yet at the time the recipe is run. It seems that perhaps if sslserver was built before httpserver then that might solve the problem (as httpserver does depend on sslserver), but I have no idea how any of that is decided behind the scenes and why it works under some scenarios (e.g. when built from QtCreator, or using specific terminal commands as mentioned).

The project structure is:

├── qthttpserver.pro
├── examples
│   ├── examples.pro
│   └── httpserver
│       ├── httpserver.pro
│       └── simple
│           └── simple.pro
├── src
│   ├── src.pro
│   ├── 3rdparty
│   │   ├── http-parser
│   │   │   └── Makefile
│   │   └── http-parser.pri
│   ├── httpserver
│   │   └── httpserver.pro
│   └── sslserver
│       └── sslserver.pro
└── tests
    ├── auto
    │   ├── auto.pro
    │   ├── cmake
    │   │   ├── CMakeLists.txt
    │   │   ├── abstracthttpserver
    │   │   │   └── CMakeLists.txt
    │   │   └── cmake.pro
    │   ├── qabstracthttpserver
    │   │   └── qabstracthttpserver.pro
    │   ├── qhttpserver
    │   │   └── qhttpserver.pro
    │   ├── qhttpserverresponder
    │   │   └── qhttpserverresponder.pro
    │   ├── qhttpserverresponse
    │   │   └── qhttpserverresponse.pro
    │   └── qhttpserverrouter
    │       └── qhttpserverrouter.pro
    └── tests.pro

[Dane 0]

Looking a bit more closely, it seems like sslserver is optional; src.pro contains the following:

qtConfig(ssl) {
    SUBDIRS += sslserver
    httpserver.depends = sslserver
}

and there are similar conditionals in the httpserver project:

#if QT_CONFIG(ssl)
#include <QtSslServer/qsslserver.h>
#include <QSslCertificate>
#include <QSslKey>
#endif

[Dane 0]

Solved by adding require ../../../meta-qt5/recipes-qt/qt5/qt5.inc to the recipe (and removing inherit qmake5, as it's included in qt5.inc in any case).

Made some progress by setting OE_QMAKE_RECURSIVE = "" but then was struggling with the installation part, and eventually realised that just requiring qt5.inc solved everything.