Merge #13458: gui: Drop qt4 support

af6ac3b doc: Remove mention of Qt4 from build docs (Wladimir J. van der Laan)
462c71f test: Update travis to not test Qt4 anymore (Wladimir J. van der Laan)
907f73b gui: Remove QT_VERSION fallbacks for Qt < 5 (Wladimir J. van der Laan)
bad068a build: Build system changes to support only Qt5 (Wladimir J. van der Laan)

Pull request description:

  Implements #8263.

  Qt4.x has been EOL since 2015, and at least Gentoo has, or is going to drop support for it. I wouldn't be surprised if other Linux distributions follow.

  This removes Qt4 detection from the build system, as well as removes all Qt4 fallbacks from the code. Turns out there's more than I expected: this is going to make maintenance of the GUI code, as well as adding new features significantly easier.

  (I know there's still some references left to qt4 in RPM and Debian build script, but I don't have the knowledge how to fix them)

Tree-SHA512: d495924fd4dda6f6566ba44ee96be7cbe62e69ba1ca993b80a8449f78da852b7f1bd3e8200d57cfa1d72233c340eeff4596fb0032ecbddc715d99aea63817d3f

Author: laanwj

.travis.yml

@@ -35,8 +35,8 @@ env:
     - HOST=i686-pc-linux-gnu PACKAGES="g++-multilib python3-zmq" DEP_OPTS="NO_QT=1" RUN_TESTS=true GOAL="install" BITCOIN_CONFIG="--enable-zmq --enable-glibc-back-compat --enable-reduce-exports LDFLAGS=-static-libstdc++" CONFIG_SHELL="/bin/dash"
 # x86_64 Linux (uses qt5 dev package instead of depends Qt to speed up build and avoid timeout)
     - HOST=x86_64-unknown-linux-gnu PACKAGES="python3-zmq qtbase5-dev qttools5-dev-tools protobuf-compiler libdbus-1-dev libharfbuzz-dev libprotobuf-dev" DEP_OPTS="NO_QT=1 NO_UPNP=1 DEBUG=1 ALLOW_HOST_PACKAGES=1" RUN_TESTS=true GOAL="install" BITCOIN_CONFIG="--enable-zmq --with-gui=qt5 --enable-glibc-back-compat --enable-reduce-exports CPPFLAGS=-DDEBUG_LOCKORDER"
-# Qt4 & system libs
-    - HOST=x86_64-unknown-linux-gnu PACKAGES="python3-zmq qt4-dev-tools libssl1.0-dev libevent-dev bsdmainutils libboost-system-dev libboost-filesystem-dev libboost-chrono-dev libboost-program-options-dev libboost-test-dev libboost-thread-dev libdb5.3++-dev libminiupnpc-dev libzmq3-dev libprotobuf-dev protobuf-compiler libqrencode-dev xvfb libqt4-dev" NO_DEPENDS=1 NEED_XVFB=1 RUN_TESTS=true GOAL="install" BITCOIN_CONFIG="--enable-zmq --with-incompatible-bdb --enable-glibc-back-compat --enable-reduce-exports --with-gui=qt4 CPPFLAGS=-DDEBUG_LOCKORDER" DISPLAY=:99.0
+# x86_64 Linux (Qt5 & system libs)
+    - HOST=x86_64-unknown-linux-gnu PACKAGES="python3-zmq qtbase5-dev qttools5-dev-tools libssl1.0-dev libevent-dev bsdmainutils libboost-system-dev libboost-filesystem-dev libboost-chrono-dev libboost-program-options-dev libboost-test-dev libboost-thread-dev libdb5.3++-dev libminiupnpc-dev libzmq3-dev libprotobuf-dev protobuf-compiler libqrencode-dev" NO_DEPENDS=1 RUN_TESTS=true GOAL="install" BITCOIN_CONFIG="--enable-zmq --with-incompatible-bdb --enable-glibc-back-compat --enable-reduce-exports --with-gui=qt5 CPPFLAGS=-DDEBUG_LOCKORDER"
 # x86_64 Linux, No wallet
     - HOST=x86_64-unknown-linux-gnu PACKAGES="python3" DEP_OPTS="NO_WALLET=1" RUN_TESTS=true GOAL="install" BITCOIN_CONFIG="--enable-glibc-back-compat --enable-reduce-exports"
 # Cross-Mac
@@ -45,7 +45,7 @@ env:
 before_install:
     - export PATH=$(echo $PATH | tr ':' "\n" | sed '/\/opt\/python/d' | tr "\n" ":" | sed "s|::|:|g")
 install:
-    - env | grep -E '^(CCACHE_|WINEDEBUG|DISPLAY|BOOST_TEST_RANDOM|CONFIG_SHELL)' | tee /tmp/env
+    - env | grep -E '^(CCACHE_|WINEDEBUG|BOOST_TEST_RANDOM|CONFIG_SHELL)' | tee /tmp/env
     - if [[ $HOST = *-mingw32 ]]; then DOCKER_ADMIN="--cap-add SYS_ADMIN"; fi
     - DOCKER_ID=$(docker run $DOCKER_ADMIN -idt --mount type=bind,src=$TRAVIS_BUILD_DIR,dst=$TRAVIS_BUILD_DIR --mount type=bind,src=$CCACHE_DIR,dst=$CCACHE_DIR -w $TRAVIS_BUILD_DIR --env-file /tmp/env ubuntu:18.04)
     - DOCKER_EXEC () { docker exec $DOCKER_ID bash -c "cd $PWD && $*"; }
@@ -58,8 +58,6 @@ before_script:
     - if [ -n "$OSX_SDK" -a -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then tar -C depends/SDKs -xf depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
     - if [[ $HOST = *-mingw32 ]]; then DOCKER_EXEC update-alternatives --set $HOST-g++ \$\(which $HOST-g++-posix\); fi
     - if [ -z "$NO_DEPENDS" ]; then DOCKER_EXEC CONFIG_SHELL= make $MAKEJOBS -C depends HOST=$HOST $DEP_OPTS; fi
-    # Start xvfb if needed, as documented at https://docs.travis-ci.com/user/gui-and-headless-browsers/#Using-xvfb-to-Run-Tests-That-Require-a-GUI
-    - if [ "$NEED_XVFB" = 1 ]; then DOCKER_EXEC /sbin/start-stop-daemon --start --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -ac; fi
 script:
     - export TRAVIS_COMMIT_LOG=`git log --format=fuller -1`
     - OUTDIR=$BASE_OUTDIR/$TRAVIS_PULL_REQUEST/$TRAVIS_JOB_NUMBER-$HOST

build-aux/m4/bitcoin_qt.m4

@@ -837,7 +837,7 @@ fi
 BITCOIN_QT_INIT
 
 dnl sets $bitcoin_enable_qt, $bitcoin_enable_qt_test, $bitcoin_enable_qt_dbus
-BITCOIN_QT_CONFIGURE([$use_pkgconfig], [qt5])
+BITCOIN_QT_CONFIGURE([$use_pkgconfig])
 
 if test x$build_bitcoin_utils$build_bitcoind$bitcoin_enable_qt$use_tests$use_bench = xnonononono; then
     use_boost=no
@@ -1422,7 +1422,6 @@ echo "Options used to compile and link:"
 echo "  with wallet   = $enable_wallet"
 echo "  with gui / qt = $bitcoin_enable_qt"
 if test x$bitcoin_enable_qt != xno; then
-    echo "    qt version  = $bitcoin_qt_got_major_vers"
     echo "    with qr     = $use_qr"
 fi
 echo "  with zmq      = $use_zmq"

configure.ac

@@ -24,8 +24,6 @@ If you want to build the disk image with `make deploy` (.dmg / optional), you ne
 
     brew install librsvg
 
-NOTE: Building with Qt4 is still supported, however, could result in a broken UI. Building with Qt5 is recommended.
-
 Berkeley DB
 -----------
 It is recommended to use Berkeley DB 4.8. If you have to build it yourself,

doc/build-osx.md

@@ -100,18 +100,13 @@ ZMQ dependencies (provides ZMQ API 4.x):
 #### Dependencies for the GUI
 
 If you want to build Bitcoin-Qt, make sure that the required packages for Qt development
-are installed. Either Qt 5 or Qt 4 are necessary to build the GUI.
-If both Qt 4 and Qt 5 are installed, Qt 5 will be used. Pass `--with-gui=qt4` to configure to choose Qt4.
+are installed. Qt 5 is necessary to build the GUI.
 To build without GUI pass `--without-gui`.
 
-To build with Qt 5 (recommended) you need the following:
+To build with Qt 5 you need the following:
 
     sudo apt-get install libqt5gui5 libqt5core5a libqt5dbus5 qttools5-dev qttools5-dev-tools libprotobuf-dev protobuf-compiler
 
-Alternatively, to build with Qt 4 you need the following:
-
-    sudo apt-get install libqt4-dev libprotobuf-dev protobuf-compiler
-
 libqrencode (optional) can be installed with:
 
     sudo apt-get install libqrencode-dev
@@ -132,7 +127,7 @@ Optional:
 
     sudo dnf install miniupnpc-devel
 
-To build with Qt 5 (recommended) you need the following:
+To build with Qt 5 you need the following:
 
     sudo dnf install qt5-qttools-devel qt5-qtbase-devel protobuf-devel
 

doc/build-unix.md

@@ -23,7 +23,7 @@ These are the dependencies currently used by Bitcoin Core. You can find instruct
 | protobuf | [2.6.3](https://github.com/google/protobuf/releases) |  | No |  |  |
 | Python (tests) |  | [3.4](https://www.python.org/downloads) |  |  |  |
 | qrencode | [3.4.4](https://fukuchi.org/works/qrencode) |  | No |  |  |
-| Qt | [5.7.1](https://download.qt.io/official_releases/qt/) | 4.7+ | No |  |  |
+| Qt | [5.7.1](https://download.qt.io/official_releases/qt/) | 5.x | No |  |  |
 | XCB |  |  |  |  | [Yes](https://github.com/bitcoin/bitcoin/blob/master/depends/packages/qt.mk#L94) (Linux only) |
 | xkbcommon |  |  |  |  | [Yes](https://github.com/bitcoin/bitcoin/blob/master/depends/packages/qt.mk#L93) (Linux only) |
 | ZeroMQ | [4.2.3](https://github.com/zeromq/libzmq/releases) |  | No |  |  |

doc/dependencies.md

@@ -1,6 +1,6 @@
 This directory contains the BitcoinQT graphical user interface (GUI). It uses the cross-platform framework [Qt](https://www1.qt.io/developers/).
 
-The current precise version for Qt 5 is specified in [qt.mk](/depends/packages/qt.mk). Qt 4 is also supported (see [#8263](https://github.com/bitcoin/bitcoin/issues/8263)).
+The current precise version for Qt 5 is specified in [qt.mk](/depends/packages/qt.mk).
 
 ## Compile and run
 
@@ -16,7 +16,7 @@ To run:
 
 ### forms
 
-Contains [Designer UI](http://doc.qt.io/qt-5.9/designer-using-a-ui-file.html) files. They are created with [Qt Creator](#using-qt-creator-as-ide), but can be edited using any text editor.
+Contains [Designer UI](https://doc.qt.io/qt-5.9/designer-using-a-ui-file.html) files. They are created with [Qt Creator](#using-qt-creator-as-ide), but can be edited using any text editor.
 
 ### locale
 
@@ -36,7 +36,7 @@ Represents the main window of the Bitcoin UI.
 
 ### \*model.(h/cpp)
 
-The model. When it has a corresponding controller, it generally inherits from  [QAbstractTableModel](http://doc.qt.io/qt-5/qabstracttablemodel.html). Models that are used by controllers as helpers inherit from other Qt classes like [QValidator](http://doc.qt.io/qt-5/qvalidator.html).
+The model. When it has a corresponding controller, it generally inherits from  [QAbstractTableModel](https://doc.qt.io/qt-5/qabstracttablemodel.html). Models that are used by controllers as helpers inherit from other Qt classes like [QValidator](https://doc.qt.io/qt-5/qvalidator.html).
 
 ClientModel is used by the main application `bitcoingui` and several models like `peertablemodel`.
 
@@ -46,7 +46,7 @@ A controller. `:NAMEpage.cpp` generally includes `:NAMEmodel.h` and `forms/:NAME
 
 ### \*dialog.(h/cpp)
 
-Various dialogs, e.g. to open a URL. Inherit from [QDialog](http://doc.qt.io/qt-4.8/qdialog.html).
+Various dialogs, e.g. to open a URL. Inherit from [QDialog](https://doc.qt.io/qt-5/qdialog.html).
 
 ### paymentserver.(h/cpp)
 

src/qt/README.md

@@ -160,13 +160,8 @@ void AddressBookPage::setModel(AddressTableModel *_model)
     ui->tableView->sortByColumn(0, Qt::AscendingOrder);
 
     // Set column widths
-#if QT_VERSION < 0x050000
-    ui->tableView->horizontalHeader()->setResizeMode(AddressTableModel::Label, QHeaderView::Stretch);
-    ui->tableView->horizontalHeader()->setResizeMode(AddressTableModel::Address, QHeaderView::ResizeToContents);
-#else
     ui->tableView->horizontalHeader()->setSectionResizeMode(AddressTableModel::Label, QHeaderView::Stretch);
     ui->tableView->horizontalHeader()->setSectionResizeMode(AddressTableModel::Address, QHeaderView::ResizeToContents);
-#endif
 
     connect(ui->tableView->selectionModel(), SIGNAL(selectionChanged(QItemSelection,QItemSelection)),
         this, SLOT(selectionChanged()));

src/qt/addressbookpage.cpp

@@ -52,9 +52,7 @@ class BanTablePriv
         node.getBanned(banMap);
 
         cachedBanlist.clear();
-#if QT_VERSION >= 0x040700
         cachedBanlist.reserve(banMap.size());
-#endif
         for (const auto& entry : banMap)
         {
             CCombinedBan banEntry;

src/qt/bantablemodel.cpp

@@ -55,13 +55,6 @@
 
 #if defined(QT_STATICPLUGIN)
 #include <QtPlugin>
-#if QT_VERSION < 0x050000
-Q_IMPORT_PLUGIN(qcncodecs)
-Q_IMPORT_PLUGIN(qjpcodecs)
-Q_IMPORT_PLUGIN(qtwcodecs)
-Q_IMPORT_PLUGIN(qkrcodecs)
-Q_IMPORT_PLUGIN(qtaccessiblewidgets)
-#else
 #if QT_VERSION < 0x050400
 Q_IMPORT_PLUGIN(AccessibleFactory)
 #endif
@@ -73,11 +66,6 @@ Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin);
 Q_IMPORT_PLUGIN(QCocoaIntegrationPlugin);
 #endif
 #endif
-#endif
-
-#if QT_VERSION < 0x050000
-#include <QTextCodec>
-#endif
 
 // Declare meta types used for QMetaObject::invokeMethod
 Q_DECLARE_METATYPE(bool*)
@@ -151,16 +139,6 @@ static void initTranslations(QTranslator &qtTranslatorBase, QTranslator &qtTrans
 }
 
 /* qDebug() message handler --> debug.log */
-#if QT_VERSION < 0x050000
-void DebugMessageHandler(QtMsgType type, const char *msg)
-{
-    if (type == QtDebugMsg) {
-        LogPrint(BCLog::QT, "GUI: %s\n", msg);
-    } else {
-        LogPrintf("GUI: %s\n", msg);
-    }
-}
-#else
 void DebugMessageHandler(QtMsgType type, const QMessageLogContext& context, const QString &msg)
 {
     Q_UNUSED(context);
@@ -170,7 +148,6 @@ void DebugMessageHandler(QtMsgType type, const QMessageLogContext& context, cons
         LogPrintf("GUI: %s\n", msg.toStdString());
     }
 }
-#endif
 
 /** Class encapsulating Bitcoin Core startup and shutdown.
  * Allows running startup and shutdown in a different thread from the UI thread.
@@ -586,12 +563,6 @@ int main(int argc, char *argv[])
     // Do not refer to data directory yet, this can be overridden by Intro::pickDataDirectory
 
     /// 1. Basic Qt initialization (not dependent on parameters or configuration)
-#if QT_VERSION < 0x050000
-    // Internal string conversion is all UTF-8
-    QTextCodec::setCodecForTr(QTextCodec::codecForName("UTF-8"));
-    QTextCodec::setCodecForCStrings(QTextCodec::codecForTr());
-#endif
-
     Q_INIT_RESOURCE(bitcoin);
     Q_INIT_RESOURCE(bitcoin_locale);
 
@@ -722,17 +693,12 @@ int main(int argc, char *argv[])
     /// 9. Main GUI initialization
     // Install global event filter that makes sure that long tooltips can be word-wrapped
     app.installEventFilter(new GUIUtil::ToolTipToRichTextFilter(TOOLTIP_WRAP_THRESHOLD, &app));
-#if QT_VERSION < 0x050000
-    // Install qDebug() message handler to route to debug.log
-    qInstallMsgHandler(DebugMessageHandler);
-#else
 #if defined(Q_OS_WIN)
     // Install global event filter for processing Windows session related Windows messages (WM_QUERYENDSESSION and WM_ENDSESSION)
     qApp->installNativeEventFilter(new WinShutdownMonitor());
 #endif
     // Install qDebug() message handler to route to debug.log
     qInstallMessageHandler(DebugMessageHandler);
-#endif
     // Allow parameter interaction before we create the options model
     app.parameterSetup();
     // Load GUI settings from QSettings
@@ -753,7 +719,7 @@ int main(int argc, char *argv[])
         // so the GUI thread won't be held up.
         if (node->baseInitialize()) {
             app.requestInitialize();
-#if defined(Q_OS_WIN) && QT_VERSION >= 0x050000
+#if defined(Q_OS_WIN)
             WinShutdownMonitor::registerShutdownBlockReason(QObject::tr("%1 didn't yet exit safely...").arg(QObject::tr(PACKAGE_NAME)), (HWND)app.getMainWinId());
 #endif
             app.exec();