Diff: Fix comment block highlighting in hunks

apps/lib/diff/diffeditor.cpp

@@ -14,9 +14,17 @@
 #include <QTextBlock>
 
 #include <KLocalizedString>
+#include <KSyntaxHighlighting/Definition>
 #include <KSyntaxHighlighting/Format>
+#include <KSyntaxHighlighting/State>
 #include <KTextEditor/Editor>
 
+DiffSyntaxHighlighter::DiffSyntaxHighlighter(QTextDocument *parent, DiffWidget *diffWidget)
+    : KSyntaxHighlighting::SyntaxHighlighter(parent)
+    , m_diffWidget(diffWidget)
+{
+}
+
 void DiffSyntaxHighlighter::applyFormat(int offset, int length, const KSyntaxHighlighting::Format &format)
 {
     if (format.textStyle() == KSyntaxHighlighting::Theme::TextStyle::Error) {
@@ -25,6 +33,21 @@ void DiffSyntaxHighlighter::applyFormat(int offset, int length, const KSyntaxHig
     KSyntaxHighlighting::SyntaxHighlighter::applyFormat(offset, length, format);
 }
 
+void DiffSyntaxHighlighter::highlightBlock(const QString &text)
+{
+    // Delete user data i.e., the stored state in the block
+    // when we encounter a hunk to avoid issues like everything
+    // is commented because previous hunk ended with an unclosed
+    // comment block
+    if (m_diffWidget->isHunk(currentBlock().blockNumber())) {
+        auto prevBlock = currentBlock().previous();
+        const auto prevData = prevBlock.userData();
+        delete prevData;
+        prevBlock.setUserData(new QTextBlockUserData);
+    }
+    KSyntaxHighlighting::SyntaxHighlighter::highlightBlock(text);
+}
+
 DiffEditor::DiffEditor(DiffParams::Flags f, QWidget *parent)
     : QPlainTextEdit(parent)
     , m_lineNumArea(new LineNumArea(this))

apps/lib/diff/diffeditor.h

@@ -15,13 +15,17 @@
 class DiffSyntaxHighlighter final : public KSyntaxHighlighting::SyntaxHighlighter
 {
 public:
-    using KSyntaxHighlighting::SyntaxHighlighter::SyntaxHighlighter;
-    void applyFormat(int offset, int length, const KSyntaxHighlighting::Format &format) override;
+    DiffSyntaxHighlighter(QTextDocument *parent, class DiffWidget *diffWidget);
 
+    void highlightBlock(const QString &text) override;
+    void applyFormat(int offset, int length, const KSyntaxHighlighting::Format &format) override;
     void applyFolding(int, int, KSyntaxHighlighting::FoldingRegion) override
     {
         // no folding
     }
+
+private:
+    class DiffWidget *const m_diffWidget;
 };
 
 #if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)

apps/lib/diff/diffwidget.cpp

@@ -35,8 +35,8 @@ DiffWidget::DiffWidget(DiffParams p, QWidget *parent)
     layout->addWidget(m_left);
     layout->addWidget(m_right);
 
-    leftHl = new DiffSyntaxHighlighter(m_left->document());
-    rightHl = new DiffSyntaxHighlighter(m_right->document());
+    leftHl = new DiffSyntaxHighlighter(m_left->document(), this);
+    rightHl = new DiffSyntaxHighlighter(m_right->document(), this);
     leftHl->setTheme(KTextEditor::Editor::instance()->theme());
     rightHl->setTheme(KTextEditor::Editor::instance()->theme());
 

apps/lib/diff/diffwidget.h

@@ -64,8 +64,8 @@ private:
 
     class DiffEditor *m_left;
     class DiffEditor *m_right;
-    KSyntaxHighlighting::SyntaxHighlighter *leftHl;
-    KSyntaxHighlighting::SyntaxHighlighter *rightHl;
+    KSyntaxHighlighting::AbstractHighlighter *leftHl;
+    KSyntaxHighlighting::AbstractHighlighter *rightHl;
     DiffStyle m_style = SideBySide;
     DiffParams m_params;
     QByteArray m_rawDiff; // Raw diff saved as is