frontend/qt: update to Qt6 on linux

- Needs a newer linuxdeployqt version that supports Qt6 and Qt6
  WebEngine. since linuxdeployqt is not maintained anymore and the
  commit that adds support for it does not have a permanent
  tag/release, we re-release their latest `continuous` release at
  https://github.com/BitBoxSwiss/linuxdeployqt/releases/tag/bitbox-1
  and use that.
- We don't compile Qt from sources anymore, as it does not work with
  the Ubuntu 20 cmake (too old) and it doesn't work with the newest
  cmake (currently 3.31) - there is some webengine cmake
  incompatibility. Instead of trying to figure all of this out, we use
  the excellent aqtinstall tool instead to fetch binaries. We also use
  pre-built binaries on macOS/Windows already, compiling from source
  on linux was an exception.

Dockerfile

@@ -13,7 +13,9 @@
 # limitations under the License.
 FROM thyrlian/android-sdk:4.0 as android
 
-FROM shiftcrypto/qt5:4
+FROM ubuntu:20.04
+
+ENV DEBIAN_FRONTEND noninteractive
 
 # Android
 COPY --from=android /opt/android-sdk /opt/android-sdk
@@ -28,6 +30,6 @@ ENV PATH $GOROOT/bin:$GOPATH/bin:$PATH
 ADD Makefile /tmp/
 RUN make -C /tmp/ envinit
 
-ENV PATH /opt/qt5/bin:$PATH
+ENV PATH /opt/qt6/6.2.4/gcc_64/bin:/opt/qt6/6.2.4/gcc_64/libexec:$PATH
 
 CMD ["bash"]

frontends/qt/Makefile

@@ -31,7 +31,7 @@ linux:
 	mv build/BitBox build/linux-tmp
 	cp build/assets.rcc build/linux-tmp/
 	cp server/libserver.so build/linux-tmp
-	cd build/linux-tmp && /opt/linuxdeployqt-7-x86_64.AppImage BitBox -bundle-non-qt-libs -unsupported-allow-new-glibc
+	cd build/linux-tmp && /opt/linuxdeployqt-continuous-x86_64.AppImage BitBox -bundle-non-qt-libs -unsupported-allow-new-glibc
 	cp /usr/lib/x86_64-linux-gnu/nss/* build/linux-tmp/lib
 	cp -aR resources/linux build/tmp-deb
 	cp resources/linux/usr/share/applications/bitbox.desktop build/linux-tmp
@@ -41,9 +41,8 @@ linux:
 	cd build/linux && fpm --after-install ../../resources/deb-afterinstall.sh -s dir -t deb -n bitbox -v 4.45.0 -C ../tmp-deb/
 	cd build/linux && fpm --after-install ../../resources/deb-afterinstall.sh -s dir -t rpm -n bitbox -v 4.45.0 -C ../tmp-deb/
 	# create AppImage
-	cd build/linux-tmp && /opt/linuxdeployqt-7-x86_64.AppImage BitBox -appimage -unsupported-allow-new-glibc
+	cd build/linux-tmp && /opt/linuxdeployqt-continuous-x86_64.AppImage BitBox -appimage -unsupported-allow-new-glibc
 	mv build/linux-tmp/BitBoxApp-*-x86_64.AppImage build/linux/
-	rm build/linux-tmp/libserver.so
 osx:
 	$(MAKE) clean
 	cd server && $(MAKE) macosx

frontends/qt/main.cpp

@@ -174,7 +174,11 @@ class WebEngineView : public QWebEngineView {
             page()->action(QWebEnginePage::SelectAll),
             page()->action(QWebEnginePage::Unselect),
         };
+#if QT_VERSION_MAJOR >= 6
+        QMenu *menu = createStandardContextMenu();
+#else
         QMenu *menu = page()->createStandardContextMenu();
+#endif
         for (const auto action : menu->actions()) {
             if (whitelist.find(action) == whitelist.cend()) {
                 menu->removeAction(action);

scripts/docker_install.sh

@@ -40,20 +40,55 @@ apt-get install -y --no-install-recommends \
         file \
         libtiff-dev \
         libxkbcommon-x11-dev \
-        libxrandr-dev
+        libxrandr-dev \
+        libxcb-xinerama0 \
+        libxcb-xkb-dev \
+        libxcb-render-util0 \
+        libxcb-image0 \
+        libxcb-keysyms1 \
+        libxcb-icccm4 \
+        libxcb-randr0 \
+        libxcb-shape0 \
+        libxcb-xinput0 \
+        libcups2 \
+        libgl1-mesa-dev \
+        libegl1-mesa-dev \
+        libfontconfig1-dev \
+        libfreetype6-dev \
+        libxi-dev \
+        libxcursor-dev \
+        libxrender-dev \
+        libxss-dev \
+        libxcomposite-dev \
+        libasound2-dev \
+        libxtst-dev \
+        libxslt-dev \
+        libnss3-dev \
+        libicu-dev \
+        libpcre2-16-0 \
+        libxkbfile-dev
+
+# Install Qt libs. python3-dev is needed to compile aqtinstall.
+apt-get -y install --no-install-recommends python3-pip python3-dev
+pip install -U pip && pip install aqtinstall
+# Not sure why we need qtpositioning - app compilation fails without. Maybe the webengine depends on it.
+# qtpositioning depends on qtserialport.
+# qtwebechannel is for the JS/backend bridge.
+# qtwebengine is for rendering the frontend.
+aqt install-qt linux desktop 6.2.4 -m qtpositioning qtserialport qtwebchannel qtwebengine --outputdir /opt/qt6
 
 npm install -g npm@10
 npm install -g locize-cli
 
 mkdir -p /opt/go_dist
 curl https://dl.google.com/go/go1.22.4.linux-amd64.tar.gz | tar -xz -C /opt/go_dist
 
-# Needed for qt5. fuse is needed to run the linuxdeployqt appimage.
+# fuse is needed to run the linuxdeployqt appimage.
 apt-get install -y --no-install-recommends fuse
 cd /opt && \
-    wget https://github.com/probonopd/linuxdeployqt/releases/download/7/linuxdeployqt-7-x86_64.AppImage && \
-    echo "645276306a801d7154d59e5b4b3c2fac3d34e09be57ec31f6d9a09814c6c162a /opt/linuxdeployqt-7-x86_64.AppImage" | sha256sum -c - && \
-    chmod +x /opt/linuxdeployqt-7-x86_64.AppImage
+    wget https://github.com/BitBoxSwiss/linuxdeployqt/releases/download/bitbox-1/linuxdeployqt-continuous-x86_64.AppImage  && \
+    echo "3850e767986be94cfb0818983df2da2d82bea6d8742aa373d810fba90eb5c65c /opt/linuxdeployqt-continuous-x86_64.AppImage" | sha256sum -c - && \
+    chmod +x /opt/linuxdeployqt-continuous-x86_64.AppImage
 
 # Install fpm to create deb/rpm packages
 apt-get install -y --no-install-recommends \