Initial commit

1 files changed, 106 insertions, 0 deletions

diff --git a/qtbug-74252.patch b/qtbug-74252.patch
new file mode 100644
index 000000000000..818f859d2541
--- /dev/null
+++ b/qtbug-74252.patch
@@ -0,0 +1,106 @@
+From add92a551cf601b5c9e074046326f95ccc38062e Mon Sep 17 00:00:00 2001
+From: Albert Astals Cid <aacid@kde.org>
+Date: Sat, 23 May 2020 01:35:18 +0200
+Subject: [PATCH] Do not fully initialize QIconLoader when setting the fallback
+ theme
+
+We need this because without this patch you get bugs both
+if you call QIcon::setFallbackThemeName before creating the QGuiApplication and
+if you call QIcon::setFallbackThemeName after creating QGuiApplication
+
+Why do you get a bug if you call QIconLoader::setFallbackThemeName
+before creating the QGuiApplication:
+ * QIcon::setFallbackThemeName calls QIconLoader::instance
+ * QIconLoader::instance calls QIconLoader::ensureInitialized
+ * QIconLoader::ensureInitialized calls systemThemeName
+ * systemThemeName asks the current QPlatformTheme for its
+   QPlatformTheme::SystemIconThemeName
+ * But since we're calling this before creating the QGuiApplication
+   there is no current QPlatformTheme yet, so systemThemeName
+   is set to empty, which is obviously not what we want
+
+Why do you get a bug if you call QIconLoader::setFallbackThemeName
+after creating the QGuiApplication:
+ * QGuiApplicationPrivate::init calls
+   QGuiApplicationPrivate::createPlatformIntegration
+ * QGuiApplicationPrivate::createPlatformIntegration sets the
+   current QPlatformTheme and at the end of the very same function
+   uses QIcon::fromTheme
+ * Since we haven't called QIconLoader::setFallbackThemeName yet
+   there is at least one icon lookup that doesn't take
+   the fallback theme we would like to have into account
+
+This patch makes it so calling QIconLoader::setFallbackThemeName
+before creating the QGuiApplication works.
+
+The only thing we want to do from QIcon::setFallbackThemeName is set
+the internal m_userFallbackTheme, it doesn't care about doing
+further initialization of QIconLoader, if it's done, great it's done,
+if it is not initialized yet, great it will be initialized later
+when someone actually tries to use the QIconloader.
+
+So it's OK for ensureInitialized() to return early if there is no
+platform theme yet, because it will be called again later.
+
+Pick-to: 5.12
+Pick-to: 5.15
+Fixes: QTBUG-74252
+Change-Id: I65268fc3d3d0bd282d76c76cf75e495bcc9d1a30
+Done-with: Albert Astals Cid <albert.astals.cid@kdab.com>
+Reviewed-by: Albert Astals Cid <albert.astals.cid@kdab.com>
+Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
+---
+ src/gui/image/qicon.cpp       |  3 +++
+ src/gui/image/qiconloader.cpp | 15 ++++++++++++---
+ 2 files changed, 15 insertions(+), 3 deletions(-)
+
+diff --git a/src/gui/image/qicon.cpp b/src/gui/image/qicon.cpp
+index 36f499711e9..91da21c477d 100644
+--- a/src/gui/image/qicon.cpp
++++ b/src/gui/image/qicon.cpp
+@@ -1238,6 +1238,9 @@ QString QIcon::fallbackThemeName()
+     themeSearchPath() containing an index.theme
+     file describing its contents.
+ 
++    \note This should be done before creating \l QGuiApplication, to ensure
++    correct initialization.
++
+     \sa fallbackThemeName(), themeSearchPaths(), themeName()
+ */
+ void QIcon::setFallbackThemeName(const QString &name)
+diff --git a/src/gui/image/qiconloader.cpp b/src/gui/image/qiconloader.cpp
+index 15ab1b3cd90..3fa3bb9c598 100644
+--- a/src/gui/image/qiconloader.cpp
++++ b/src/gui/image/qiconloader.cpp
+@@ -112,10 +112,9 @@ extern QFactoryLoader *qt_iconEngineFactoryLoader(); // qicon.cpp
+ void QIconLoader::ensureInitialized()
+ {
+     if (!m_initialized) {
++        if (!QGuiApplicationPrivate::platformTheme())
++            return; // it's too early: try again later (QTBUG-74252)
+         m_initialized = true;
+-
+-        Q_ASSERT(qApp);
+-
+         m_systemTheme = systemThemeName();
+ 
+         if (m_systemTheme.isEmpty())
+@@ -125,6 +124,16 @@ void QIconLoader::ensureInitialized()
+     }
+ }
+ 
++/*!
++    \internal
++    Gets an instance.
++
++    \l QIcon::setFallbackThemeName() should be called before QGuiApplication is
++    created, to avoid a race condition (QTBUG-74252). When this function is
++    called from there, ensureInitialized() does not succeed because there
++    is no QPlatformTheme yet, so systemThemeName() is empty, and we don't want
++    m_systemTheme to get intialized to the fallback theme instead of the normal one.
++*/
+ QIconLoader *QIconLoader::instance()
+ {
+    iconLoaderInstance()->ensureInitialized();
+-- 
+2.16.3