HunkHeader resizes itself to not interfere with line wrapping

src/ui/CMakeLists.txt

@@ -11,6 +11,7 @@ add_library(
   ContextMenuButton.cpp
   DetailView.cpp
   DiffView/DiffView.cpp
+  DiffView/HunkHeader.cpp
   DiffView/HunkWidget.cpp
   DiffView/FileWidget.cpp
   DiffView/FileLabel.cpp

src/ui/DiffView/HunkHeader.cpp

@@ -0,0 +1,42 @@
+#include "HunkHeader.h"
+#include "DiffView.h"
+#include "../RepoView.h"
+
+#include <QPainter>
+#include <QPainterPath>
+
+HunkHeader::HunkHeader(const QString &name, bool submodule, QWidget *parent)
+    : QWidget(parent), mName(name) {
+  setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
+}
+
+void HunkHeader::setName(const QString &name) { mName = name; }
+
+void HunkHeader::setOldName(const QString &oldName) { mOldName = oldName; }
+
+QSize HunkHeader::sizeHint() const {
+  QFontMetrics fm = fontMetrics();
+  int width = fm.boundingRect(mName).width() + 2;
+  if (!mOldName.isEmpty())
+    width += fm.boundingRect(mOldName).width() + DiffViewStyle::kArrowWidth;
+  return QSize(width, fm.lineSpacing());
+}
+
+void HunkHeader::paintEvent(QPaintEvent *event) {
+  QPainter painter(this);
+  painter.setRenderHint(QPainter::Antialiasing);
+  QFontMetrics fm = fontMetrics();
+  QRect rect = fm.boundingRect(0, 0, this->rect().width(), 300,
+                               Qt::AlignLeft | Qt::ElideRight, mName);
+  painter.drawText(rect, Qt::AlignLeft | Qt::ElideRight, mName);
+}
+
+void HunkHeader::mouseReleaseEvent(QMouseEvent *event) {
+  if (!rect().contains(event->pos()))
+    return;
+
+  QUrl url;
+  url.setScheme("submodule");
+  url.setPath(mName);
+  RepoView::parentView(this)->visitLink(url.toString());
+}

src/ui/DiffView/HunkHeader.h

@@ -0,0 +1,22 @@
+#ifndef HUNKHEADER_H
+#define HUNKHEADER_H
+
+#include <QWidget>
+
+class HunkHeader : public QWidget {
+public:
+  HunkHeader(const QString &name, bool submodule, QWidget *parent = nullptr);
+  void setName(const QString &name);
+  void setOldName(const QString &oldName);
+  QSize sizeHint() const override;
+
+protected:
+  void paintEvent(QPaintEvent *event) override;
+  void mouseReleaseEvent(QMouseEvent *event) override;
+
+private:
+  QString mName;
+  QString mOldName;
+};
+
+#endif // HUNKHEADER_H

src/ui/DiffView/HunkWidget.cpp

@@ -5,6 +5,7 @@
 #include "DiffView.h"
 #include "DisclosureButton.h"
 #include "EditButton.h"
+#include "HunkHeader.h"
 #include "DiscardButton.h"
 #include "app/Application.h"
 
@@ -39,15 +40,16 @@ _HunkWidget::Header::Header(const git::Diff &diff, const git::Patch &patch,
                             int index, bool lfs, bool submodule,
                             QWidget *parent)
     : QFrame(parent) {
+  setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
   setObjectName("HunkHeader");
   mCheck = new QCheckBox(this);
   mCheck->setTristate(true);
   mCheck->setVisible(diff.isStatusDiff() && !submodule &&
                      !patch.isConflicted());
 
-  QString header = (index >= 0) ? patch.header(index) : QString();
-  QString escaped = header.trimmed().toHtmlEscaped();
-  QLabel *label = new QLabel(DiffViewStyle::kHunkFmt.arg(escaped), this);
+  QString headerString = (index >= 0) ? patch.header(index) : QString();
+  QString escaped = headerString.trimmed().toHtmlEscaped();
+  HunkHeader *header = new HunkHeader(escaped, submodule, this);
 
   if (patch.isConflicted()) {
     mSave = new QToolButton(this);
@@ -132,7 +134,7 @@ _HunkWidget::Header::Header(const git::Diff &diff, const git::Patch &patch,
   QHBoxLayout *layout = new QHBoxLayout(this);
   layout->setContentsMargins(4, 4, 4, 4);
   layout->addWidget(mCheck);
-  layout->addWidget(label);
+  layout->addWidget(header, 1);
   layout->addStretch();
   layout->addLayout(buttons);