M3: loadable KTextEditor plugin with M-x command palette

- OlliePlugin (KTextEditor::Plugin) + OllieView, built as olliepalette.so
  via kcoreaddons_add_plugin, installed under kf6/ktexteditor.
- M-x bound to Alt+X (single modifier, adjacent keys on a compact layout,
  ApplicationShortcut so it is always live).
- On trigger, aggregates every enabled/visible QAction from the window's
  guiFactory()->clients() action collections (keyed by objectName) and
  shows them in PaletteWidget; the chosen row triggers the QAction. The
  action's current shortcut is surfaced in the group column.
- Enable position-independent code for linking the static palette lib into
  the shared plugin module.
- Plugin metadata verified valid via KPluginMetaData.

Frecency wiring deferred (model supports it; plugin passes 0). All three
ctest suites remain green.

CMakeLists.txt

@@ -16,6 +16,8 @@ include(KDEInstallDirs)
 include(KDECMakeSettings)
 include(KDECompilerSettings NO_POLICY_SCOPE)
 
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
 find_package(Qt6 ${QT_MIN_VERSION} REQUIRED COMPONENTS Core Gui Widgets)
 find_package(Qt6 ${QT_MIN_VERSION} COMPONENTS Test)
 

README.md

@@ -51,6 +51,20 @@ QT_QPA_PLATFORM=offscreen ./build/bin/test_fuzzyranker   # run the matcher tests
 ctest --test-dir build                                   # or via ctest
 ```
 
+## Install the plugin into Kate
+
+The plugin builds to `build/bin/kf6/ktexteditor/olliepalette.so`. Drop it where
+Kate scans for KTextEditor plugins (a user path on `QT_PLUGIN_PATH`):
+
+```sh
+install -D build/bin/kf6/ktexteditor/olliepalette.so \
+  ~/.local/lib/x86_64-linux-gnu/qt6/plugins/kf6/ktexteditor/olliepalette.so
+```
+
+Then in Kate: Settings → Configure Kate → Plugins → enable
+**Ollie Command Palette**. Press **Alt+X** (M-x) to open the palette; type to
+filter, Enter or click to run.
+
 ## Status
 
 See [docs/PLAN.md](docs/PLAN.md) for the full roadmap.
@@ -61,7 +75,9 @@ See [docs/PLAN.md](docs/PLAN.md) for the full roadmap.
 - **Milestone 2 — custom palette widget: DONE.** `PaletteModel` +
   `PaletteWidget` (frameless popup, live filtering, highlighted matches,
   keyboard + mouse activation). 10 model unit tests, all green.
-- Milestone 3 — KTextEditor plugin + M-x + action registry: next.
+- Milestone 3 — KTextEditor plugin + M-x: **DONE.** Loadable `olliepalette.so`;
+  `Alt+X` opens the palette over every action in the window's GUI clients.
+- Milestone 4 — radial caret menu (mouse door): next.
 
 ## Layout
 
@@ -75,6 +91,9 @@ src/
     palettemodel.{h,cpp}  ranked, filterable list model (headless)
     palettewidget.{h,cpp} frameless command-palette popup
     test_palettemodel.cpp QTest suite
+  plugin/
+    ollieplugin.{h,cpp}   KTextEditor::Plugin + M-x action registry
+    ollieplugin.json      plugin metadata
 docs/
   PLAN.md                 goal, constraints, roadmap
 ```

docs/PLAN.md

@@ -61,13 +61,21 @@ Therefore the palette is replaced, not extended, and the replacement is built on
 - `src/palette/test_palettemodel.cpp`: 10 QTest cases, all green (filtering,
   orderless, typo, best-first ordering, frecency tie-break, highlight ranges).
 
-### M3 — KTextEditor plugin + M-x + action registry — NEXT
-- `KTextEditor::Plugin` skeleton producing a loadable `.so`.
-- Central action registry aggregating Kate built-in actions + plugin actions.
-- `M-x` (`Alt+x`) opens the M2 palette over the registry.
-- Frecency ranking: usage history feeds a score bonus.
+### M3 — KTextEditor plugin + M-x + action registry — DONE
+- `src/plugin/ollieplugin.{h,cpp}` + `ollieplugin.json`: a loadable
+  `KTextEditor::Plugin` (`olliepalette.so`) built with `kcoreaddons_add_plugin`.
+- `OllieView` (one per MainWindow) registers the **M-x** action, `Alt+X`, a
+  single modifier with the keys adjacent on a compact layout; `ApplicationShortcut`
+  context so it is always live.
+- On trigger it aggregates every enabled, visible `QAction` from the window's
+  `guiFactory()->clients()` action collections, keyed by stable `objectName`,
+  and feeds them to `PaletteWidget`. The action's current shortcut is shown in
+  the group column. Accepting a row triggers the underlying `QAction`.
+- Installs to `kf6/ktexteditor`; metadata verified valid via `KPluginMetaData`.
+- Not yet wired: frecency (the model supports a bonus, but the plugin currently
+  passes 0 for every action — usage tracking is deferred).
 
-### M4 — Radial caret menu (mouse door)
+### M4 — Radial caret menu (mouse door) — NEXT
 - Mouse-triggered radial menu positioned at the caret
   (`View::cursorToCoordinate`), flick-to-select by angle.
 - Slices invoke registry actions; one slice opens the palette / command line, so

src/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_subdirectory(fuzzy)
 add_subdirectory(palette)
+add_subdirectory(plugin)

src/plugin/CMakeLists.txt

@@ -0,0 +1,25 @@
+find_package(KF6 ${KF_MIN_VERSION} COMPONENTS
+    TextEditor
+    XmlGui
+    CoreAddons
+    I18n
+)
+
+if(NOT KF6TextEditor_FOUND)
+    message(STATUS "KF6::TextEditor not found — skipping the Kate plugin target")
+    return()
+endif()
+
+kcoreaddons_add_plugin(olliepalette
+    SOURCES ollieplugin.cpp ollieplugin.h
+    INSTALL_NAMESPACE "kf6/ktexteditor"
+)
+
+target_link_libraries(olliepalette PRIVATE
+    palette
+    KF6::TextEditor
+    KF6::XmlGui
+    KF6::CoreAddons
+    KF6::I18n
+    Qt6::Widgets
+)

src/plugin/ollieplugin.cpp

@@ -0,0 +1,159 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.0-or-later
+ */
+#include "ollieplugin.h"
+
+#include "palettewidget.h"
+
+#include <KTextEditor/MainWindow>
+
+#include <KActionCollection>
+#include <KXMLGUIClient>
+#include <KXMLGUIFactory>
+#include <KLocalizedString>
+#include <KPluginFactory>
+
+#include <QAction>
+#include <QKeySequence>
+#include <QWidget>
+
+namespace katecustom
+{
+
+// ---------------------------------------------------------------------------
+// OlliePlugin
+// ---------------------------------------------------------------------------
+
+OlliePlugin::OlliePlugin(QObject *parent, const QVariantList &args)
+    : KTextEditor::Plugin(parent)
+{
+    Q_UNUSED(args);
+}
+
+OlliePlugin::~OlliePlugin() = default;
+
+QObject *OlliePlugin::createView(KTextEditor::MainWindow *mainWindow)
+{
+    return new OllieView(this, mainWindow);
+}
+
+// ---------------------------------------------------------------------------
+// OllieView
+// ---------------------------------------------------------------------------
+
+OllieView::OllieView(OlliePlugin *plugin, KTextEditor::MainWindow *mainWindow)
+    : QObject(plugin)
+    , m_mainWindow(mainWindow)
+{
+    // The one keyboard door: Alt+X (M-x). A single modifier, no chord, and the
+    // keys sit together on a compact layout.
+    auto *openAction = new QAction(i18n("Command Palette (M-x)"), this);
+    openAction->setObjectName(QStringLiteral("ollie_command_palette"));
+    openAction->setShortcut(QKeySequence(Qt::ALT | Qt::Key_X));
+    openAction->setShortcutContext(Qt::ApplicationShortcut);
+    connect(openAction, &QAction::triggered, this, &OllieView::showCommandPalette);
+
+    // Attach the shortcut to the window so it is always live.
+    if (QWidget *w = m_mainWindow->window()) {
+        w->addAction(openAction);
+    }
+}
+
+OllieView::~OllieView()
+{
+    delete m_palette;
+}
+
+void OllieView::collectActions(QHash<QString, QPointer<QAction>> &out) const
+{
+    KXMLGUIFactory *factory = m_mainWindow->guiFactory();
+    if (!factory) {
+        return;
+    }
+
+    const QList<KXMLGUIClient *> clients = factory->clients();
+    for (KXMLGUIClient *client : clients) {
+        KActionCollection *coll = client->actionCollection();
+        if (!coll) {
+            continue;
+        }
+        const QList<QAction *> actions = coll->actions();
+        for (QAction *action : actions) {
+            if (!action || action->isSeparator()) {
+                continue;
+            }
+            // Only offer things the user could actually invoke now.
+            if (!action->isEnabled() || !action->isVisible()) {
+                continue;
+            }
+            const QString label = action->text().remove(QLatin1Char('&')).trimmed();
+            if (label.isEmpty()) {
+                continue;
+            }
+            // Prefer the stable objectName as id; fall back to the label.
+            QString id = action->objectName();
+            if (id.isEmpty()) {
+                id = label;
+            }
+            if (!out.contains(id)) {
+                out.insert(id, action);
+            }
+        }
+    }
+}
+
+void OllieView::showCommandPalette()
+{
+    if (!m_palette) {
+        m_palette = new PaletteWidget(m_mainWindow->window());
+        connect(m_palette, &PaletteWidget::activatedId, this, &OllieView::runAction);
+    }
+
+    m_actionsById.clear();
+    collectActions(m_actionsById);
+
+    QList<PaletteItem> items;
+    items.reserve(m_actionsById.size());
+    for (auto it = m_actionsById.cbegin(); it != m_actionsById.cend(); ++it) {
+        QAction *action = it.value();
+        if (!action) {
+            continue;
+        }
+        PaletteItem item;
+        item.id = it.key();
+        item.label = action->text().remove(QLatin1Char('&')).trimmed();
+        // Show the current shortcut as the group column hint, when present.
+        const QString sc = action->shortcut().toString(QKeySequence::NativeText);
+        item.group = sc;
+        items.push_back(item);
+    }
+
+    m_palette->setItems(items);
+
+    // Center the palette near the top of the active window.
+    if (QWidget *w = m_mainWindow->window()) {
+        const QSize sz = m_palette->size();
+        const QPoint topLeft = w->mapToGlobal(QPoint((w->width() - sz.width()) / 2,
+                                                      w->height() / 6));
+        m_palette->move(topLeft);
+    }
+
+    m_palette->activate();
+}
+
+void OllieView::runAction(const QString &actionId)
+{
+    QPointer<QAction> action = m_actionsById.value(actionId);
+    if (action) {
+        action->trigger();
+    }
+}
+
+} // namespace katecustom
+
+// K_PLUGIN_FACTORY generates the factory and the moc-level registration. The
+// matching .moc include is required in this translation unit.
+K_PLUGIN_FACTORY_WITH_JSON(OlliePluginFactory, "ollieplugin.json",
+                           registerPlugin<katecustom::OlliePlugin>();)
+
+#include "ollieplugin.moc"

src/plugin/ollieplugin.h

@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.0-or-later
+ *
+ * The Ollie command-palette plugin for Kate / KTextEditor.
+ *
+ * OlliePlugin is the KTextEditor::Plugin entry point. For every MainWindow the
+ * host creates an OllieView, which registers the "Command Palette (M-x)" action
+ * (Alt+X) and, when triggered, gathers every QAction currently exposed by the
+ * window's GUI clients into a PaletteWidget for orderless fuzzy selection.
+ */
+#ifndef KATECUSTOM_OLLIEPLUGIN_H
+#define KATECUSTOM_OLLIEPLUGIN_H
+
+#include <KTextEditor/Plugin>
+
+#include <QObject>
+#include <QPointer>
+#include <QHash>
+
+class QAction;
+
+namespace KTextEditor
+{
+class MainWindow;
+}
+
+namespace katecustom
+{
+
+class PaletteWidget;
+
+class OlliePlugin : public KTextEditor::Plugin
+{
+    Q_OBJECT
+
+public:
+    explicit OlliePlugin(QObject *parent, const QVariantList &args = {});
+    ~OlliePlugin() override;
+
+    QObject *createView(KTextEditor::MainWindow *mainWindow) override;
+};
+
+class OllieView : public QObject
+{
+    Q_OBJECT
+
+public:
+    OllieView(OlliePlugin *plugin, KTextEditor::MainWindow *mainWindow);
+    ~OllieView() override;
+
+private Q_SLOTS:
+    void showCommandPalette();
+    void runAction(const QString &actionId);
+
+private:
+    // Collect every unique, enabled, visible QAction reachable from the
+    // window's GUI factory clients. Keyed by a stable id for lookup on accept.
+    void collectActions(QHash<QString, QPointer<QAction>> &out) const;
+
+    KTextEditor::MainWindow *m_mainWindow;
+    PaletteWidget *m_palette = nullptr;
+    QHash<QString, QPointer<QAction>> m_actionsById;
+};
+
+} // namespace katecustom
+
+#endif

src/plugin/ollieplugin.json

@@ -0,0 +1,14 @@
+{
+    "KPlugin": {
+        "Authors": [
+            {
+                "Name": "Levi Neely"
+            }
+        ],
+        "Description": "Menu-free, mouse-first command access: an orderless fuzzy command palette (M-x).",
+        "Icon": "code-context",
+        "License": "LGPL-2.0-or-later",
+        "Name": "Ollie Command Palette",
+        "Version": "0.1.0"
+    }
+}