[kdevelop/kdevelop] plugins: Add gdb pretty-printer for QText*Format

Git commit 1791125742c92b0372c58e8dda1bd1c79bb79057 by David Faure.
Committed on 03/08/2026 at 09:14.
Pushed by dfaure into branch 'master'.

Add gdb pretty-printer for QText*Format

Only tested with Qt6.
Requires debug info for the private class QTextFormatPrivate,
the unittest skips itself otherwise.

M  +3    -0    plugins/debuggercommon/tests/debuggees/CMakeLists.txt
A  +40   -0    plugins/debuggercommon/tests/debuggees/qtextformat.cpp  *
M  +121  -0    plugins/gdb/printers/qt.py
M  +56   -0    plugins/gdb/unittests/test_gdbprinters.cpp
M  +1    -0    plugins/gdb/unittests/test_gdbprinters.h

The files marked with a * at the end have a non valid license. Please read: https://community.kde.org/Policies/Licensing_Policy and use the headers which are listed at that page.


https://invent.kde.org/kdevelop/kdevelop/-/commit/1791125742c92b0372c58e8dda1bd1c79bb79057

diff --git a/plugins/debuggercommon/tests/debuggees/CMakeLists.txt b/plugins/debuggercommon/tests/debuggees/CMakeLists.txt
index f054611aa3..9adb96bc41 100644
--- a/plugins/debuggercommon/tests/debuggees/CMakeLists.txt
+++ b/plugins/debuggercommon/tests/debuggees/CMakeLists.txt
@@ -123,6 +123,9 @@ target_link_libraries(debuggee_qjson Qt::Core)
 add_debuggable_executable(debuggee_qvariant SRCS qvariant.cpp)
 target_link_libraries(debuggee_qvariant Qt::Core)
 
+add_debuggable_executable(debuggee_qtextformat SRCS qtextformat.cpp)
+target_link_libraries(debuggee_qtextformat Qt::Core Qt::Gui)
+
 add_debuggable_executable(debuggee_qlistpod SRCS qlistpod.cpp)
 target_link_libraries(debuggee_qlistpod Qt::Core)
 
diff --git a/plugins/debuggercommon/tests/debuggees/qtextformat.cpp b/plugins/debuggercommon/tests/debuggees/qtextformat.cpp
new file mode 100644
index 0000000000..e4523d2085
--- /dev/null
+++ b/plugins/debuggercommon/tests/debuggees/qtextformat.cpp
@@ -0,0 +1,40 @@
+#include <QTextFormat>
+
+int main()
+{
+    QTextFormat invalidFormat;
+    QTextFormat obsoleteFormat(4); // the obsolete QTextFormat::TableFormat
+    QTextFormat userFormat(QTextFormat::UserFormat);
+    QTextFormat userFormat3(QTextFormat::UserFormat + 3);
+
+    QTextCharFormat emptyCharFormat;
+
+    QTextBlockFormat blockFormat;
+    blockFormat.setTopMargin(10);
+
+    QTextCharFormat charFormat;
+    charFormat.setFontItalic(true);
+    charFormat.setToolTip(QStringLiteral("some tooltip"));
+    // FontCapitalization shares its value with the FirstFontProperty alias
+    charFormat.setFontCapitalization(QFont::AllUppercase);
+    // FontSizeAdjustment shares its value with the FontSizeIncrement alias
+    charFormat.setProperty(QTextFormat::FontSizeAdjustment, 1);
+    charFormat.setProperty(QTextFormat::UserProperty + 1, 42); // a property without a name
+
+    QTextListFormat listFormat;
+    listFormat.setIndent(2);
+
+    QTextFrameFormat frameFormat;
+    frameFormat.setBorder(3);
+
+    QTextTableFormat tableFormat;
+    tableFormat.setCellPadding(4);
+
+    QTextImageFormat imageFormat;
+    imageFormat.setName(QStringLiteral("image.png"));
+
+    QTextCharFormat userObjectFormat;
+    userObjectFormat.setObjectType(QTextFormat::UserObject + 1);
+
+    return 0; // line 39
+}
diff --git a/plugins/gdb/printers/qt.py b/plugins/gdb/printers/qt.py
index 72c988918b..3fe5174d30 100644
--- a/plugins/gdb/printers/qt.py
+++ b/plugins/gdb/printers/qt.py
@@ -1568,6 +1568,126 @@ class QVariantPrinter:
 
         return "QVariant(%s, %s)" % (type_str, value_str)
 
+class QTextFormatPrinter(PrinterBaseType):
+    "Print a QTextFormat, with its properties as children"
+
+    # QTextFormat::FormatType, without InvalidFormat and UserFormat
+    _classNames = {
+        1: "QTextBlockFormat",
+        2: "QTextCharFormat",
+        3: "QTextListFormat",
+        5: "QTextFrameFormat",
+    }
+
+    # QTextFormat::ObjectTypes, without UserObject
+    _objectTypeNames = {
+        0: "NoObject",
+        1: "ImageObject",
+        2: "TableObject",
+        3: "TableCellObject",
+    }
+
+    # Enumerators of QTextFormat::Property which are aliases for another property.
+    # Note that OldFontLetterSpacingType and OldFontStretch are real properties, not aliases.
+    _propertyAliases = ('FirstFontProperty', 'LastFontProperty', 'FontSizeIncrement',
+                        'OldFontFamily', 'OldTextUnderlineColor')
+
+    _userFormat = 100 # QTextFormat::UserFormat
+    _objectTypeProperty = 0x2f00 # QTextFormat::ObjectType
+    _userProperty = 0x100000 # QTextFormat::UserProperty
+
+    def __init__(self, val):
+        self._properties = [] # list of (name, value) pairs
+
+        formatType = int(val['format_type'])
+        if formatType == -1: # QTextFormat::InvalidFormat
+            self._string = "QTextFormat(InvalidFormat)"
+            return
+        className = self._classNames.get(formatType)
+        if className is None:
+            if formatType < self._userFormat:
+                self._string = f"QTextFormat(UnknownFormatType={formatType})"
+                return
+            # user formats have no dedicated class
+            offset = formatType - self._userFormat
+            className = "QTextFormat(UserFormat)" if offset == 0 else f"QTextFormat(UserFormat+{offset})"
+
+        d_ptr = pointer_from_possible_totally_ordered_wrapper(val['d']['d'])
+        if d_ptr: # otherwise this is a default-constructed format, without any property
+            # TODO print d_ptr['fnt'] once we have a QFont pretty-printer
+            try:
+                self._properties = self._readProperties(d_ptr['props'])
+            except gdb.error as e:
+                # QTextFormatPrivate is a private Qt class, so its debug info is often missing
+                self._string = f"{className} (cannot read the properties: {e})"
+                return
+
+        self._string = f"{className} (size = {len(self._properties)})"
+
+    @classmethod
+    def _readProperties(cls, props):
+        propertyNames = cls._readPropertyNames()
+        properties = []
+        # props is a QVector in Qt5 and a QList in Qt6, QVectorPrinter handles both
+        for _, prop in QVectorPrinter(props, "QVector").children():
+            key = int(prop['key'])
+            name = propertyNames.get(key) or cls._unnamedProperty(key)
+            properties.append((name, cls._propertyValue(key, prop['value'])))
+        return properties
+
+    @classmethod
+    def _readPropertyNames(cls):
+        "Map QTextFormat::Property values to their enumerator names"
+        names = {}
+        try:
+            enumType = gdb.lookup_type('QTextFormat::Property')
+        except gdb.error:
+            return names
+        for field in enumType.fields():
+            if field.name:
+                name = field.name.split('::')[-1]
+                if name not in cls._propertyAliases:
+                    names[int(field.enumval)] = name
+        return names
+
+    @classmethod
+    def _unnamedProperty(cls, key):
+        "Name a property which has no enumerator, i.e. a custom one, or one from a newer Qt version"
+        if key > cls._userProperty:
+            return f"UserProperty+{key - cls._userProperty}"
+        return hex(key)
+
+    @classmethod
+    def _propertyValue(cls, key, value):
+        if key != cls._objectTypeProperty or not cls._isIntVariant(value):
+            return value
+        # the int maps to the QTextFormat::ObjectTypes enum
+        objectType = int(value['d']['data']['data'].cast(gdb.lookup_type('int').pointer()).dereference())
+        if objectType >= 0x1000: # QTextFormat::UserObject
+            return f"UserObject ({objectType})"
+        return cls._objectTypeNames.get(objectType, f"UnknownObjectType ({objectType})")
+
+    @staticmethod
+    def _isIntVariant(variant):
+        "Check that the QVariant really holds an int, before reading its data as such"
+        try:
+            d = variant['d']
+            if not has_field(d, 'packedType'): # Qt5, not supported here
+                return False
+            metaType = (d['packedType'] << 2).cast(gdb.lookup_type("QtPrivate::QMetaTypeInterface").pointer())
+            return metaType['name'].string() == 'int'
+        except gdb.error:
+            return False
+
+    def to_string(self):
+        return self._string
+
+    def num_children(self):
+        return len(self._properties)
+
+    def children(self):
+        return self._properties
+
 pretty_printers_dict = {}
 
 def register_qt_printers (obj):
@@ -1613,6 +1733,7 @@ def build_dictionary ():
     pretty_printers_dict[re.compile('^QJsonDocument$')] = lambda val: QJsonDocumentPrinter(val)
     pretty_printers_dict[re.compile('^QJsonValue$')] = lambda val: QJsonValuePrinter(val)
     pretty_printers_dict[re.compile('^QJsonValue(Const|)Ref$')] = lambda val: QJsonValueConstRefPrinter(val)
+    pretty_printers_dict[re.compile('^QText[A-Za-z]*Format$')] = lambda val: QTextFormatPrinter(val)
 
 
 build_dictionary ()
diff --git a/plugins/gdb/unittests/test_gdbprinters.cpp b/plugins/gdb/unittests/test_gdbprinters.cpp
index 0c545554b4..efac1899b8 100644
--- a/plugins/gdb/unittests/test_gdbprinters.cpp
+++ b/plugins/gdb/unittests/test_gdbprinters.cpp
@@ -1118,6 +1118,62 @@ void QtPrintersTest::testQVariant()
     QVERIFY(printNext().contains("QVariant(SomeCustomType, {\n  foo = 42\n})"));
 }
 
+void QtPrintersTest::testQTextFormat()
+{
+    GdbProcess gdb(QStringLiteral("debuggee_qtextformat"));
+    gdb.execute("break qtextformat.cpp:39");
+    gdb.execute("run");
+
+    // The printer reads the members of QTextFormatPrivate, which is a private Qt class.
+    if (gdb.execute("ptype QTextFormatPrivate").contains("No symbol")) {
+        // Without that debug info the printer can only print the class name. It must not throw,
+        // waitForPrompt() fails the test if the printer raises a Python exception.
+        QVERIFY(printedValue(gdb, "charFormat").startsWith("QTextCharFormat "));
+        QSKIP("Skipping the rest because the debug info of QtGui is not available");
+    }
+
+    QCOMPARE(printedValue(gdb, "invalidFormat"), "QTextFormat(InvalidFormat)");
+    QCOMPARE(printedValue(gdb, "obsoleteFormat"), "QTextFormat(UnknownFormatType=4)");
+    QCOMPARE(printedValue(gdb, "userFormat"), "QTextFormat(UserFormat) (size = 0)");
+    QCOMPARE(printedValue(gdb, "userFormat3"), "QTextFormat(UserFormat+3) (size = 0)");
+    QCOMPARE(printedValue(gdb, "emptyCharFormat"), "QTextCharFormat (size = 0)");
+
+    QCOMPARE(printedValue(gdb, "blockFormat"), R"(QTextBlockFormat (size = 1) = {
+  BlockTopMargin = QVariant(double, 10)
+})");
+
+    QCOMPARE(printedValue(gdb, "charFormat"), R"(QTextCharFormat (size = 5) = {
+  FontItalic = QVariant(bool, true),
+  TextToolTip = QVariant(QString, "some tooltip"),
+  FontCapitalization = QVariant(int, 1),
+  FontSizeAdjustment = QVariant(int, 1),
+  UserProperty+1 = QVariant(int, 42)
+})");
+
+    QCOMPARE(printedValue(gdb, "userObjectFormat"), R"(QTextCharFormat (size = 1) = {
+  ObjectType = UserObject (4097)
+})");
+
+    // The formats below have additional properties set by their constructor, which vary between Qt versions
+    auto out = printedValue(gdb, "listFormat");
+    QVERIFY(out.startsWith("QTextListFormat (size = "));
+    QVERIFY(out.contains("ListIndent = QVariant(int, 2)"));
+
+    out = printedValue(gdb, "frameFormat");
+    QVERIFY(out.startsWith("QTextFrameFormat (size = "));
+    QVERIFY(out.contains("FrameBorder = QVariant(double, 3)"));
+
+    out = printedValue(gdb, "tableFormat");
+    QVERIFY(out.startsWith("QTextFrameFormat (size = "));
+    QVERIFY(out.contains("ObjectType = TableObject"));
+    QVERIFY(out.contains("TableCellPadding = QVariant(double, 4)"));
+
+    out = printedValue(gdb, "imageFormat");
+    QVERIFY(out.startsWith("QTextCharFormat (size = "));
+    QVERIFY(out.contains("ObjectType = ImageObject"));
+    QVERIFY(out.contains("ImageName = QVariant(QString, \"image.png\")"));
+}
+
 void QtPrintersTest::testKTextEditorTypes()
 {
     GdbProcess gdb(QStringLiteral("debuggee_ktexteditortypes"));
diff --git a/plugins/gdb/unittests/test_gdbprinters.h b/plugins/gdb/unittests/test_gdbprinters.h
index 5284b8c094..9837a03d90 100644
--- a/plugins/gdb/unittests/test_gdbprinters.h
+++ b/plugins/gdb/unittests/test_gdbprinters.h
@@ -42,6 +42,7 @@ private Q_SLOTS:
     void testQCbor();
     void testQJson();
     void testQVariant();
+    void testQTextFormat();
     void testKTextEditorTypes();
     void testKDevelopTypes();
 };