feat(rules): the rules window keeps its size and column widths

Item 75. saveGeometry() and the rule list header's saveState() go to
uistate.conf under keys of their own, written on closeEvent so a size
survives Cancel as well as Save. The 760x520 resize stays as the
first-run fallback.

The backlog's approach was wrong on one point and a test caught it. It
said to drop the resizeColumnToContents calls once a saved header state
exists, which fixes the restore and leaves the original defect standing:
with nothing saved, a width the user had just dragged was still
discarded by the next add or delete. Each column is instead auto-sized
once, on its first fill, after which the width belongs to the user
however it was set. Two flags, because the count column is filled later
by a reply from the worker.

The window stays a QDialog. Making it a top-level window needs the
unsaved-edit story that being modal currently sidesteps, and that is its
own decision rather than part of this item.

Both tests redirect XDG_STATE_HOME as well as XDG_CONFIG_HOME, so they
cannot write the real uistate.conf. The geometry is asserted on the
stored value rather than the reopened frame, per item 46: the offscreen
platform does not honour a resize.

Also corrects setFolders' doc comment, which still described the folder
list as coming from Config.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

2 files changed, 126 insertions, 6 deletions

diff --git a/src/tagrulesdialog.cpp b/src/tagrulesdialog.cpp
index 75a9cbe..61f2c21 100644
--- a/src/tagrulesdialog.cpp
+++ b/src/tagrulesdialog.cpp
@@ -20,8 +20,11 @@
 
 #include <QButtonGroup>
 #include <QCheckBox>
+#include <QCloseEvent>
 #include <QComboBox>
 #include <QDialogButtonBox>
+#include <QDir>
+#include <QFileInfo>
 #include <QFormLayout>
 #include <QHBoxLayout>
 #include <QHeaderView>
@@ -31,10 +34,13 @@
 #include <QPlainTextEdit>
 #include <QPushButton>
 #include <QRadioButton>
+#include <QSettings>
 #include <QSpinBox>
 #include <QTreeWidget>
 #include <QVBoxLayout>
 
+#include "mainwindow.h"
+
 namespace {
 
 /// Columns of the rule list.
@@ -72,6 +78,9 @@ TagRulesDialog::TagRulesDialog(QWidget *parent)
     : QDialog(parent)
 {
     setWindowTitle(tr("Tagging rules"));
+    // The fallback for a first run. restoreUiState() overwrites it when a
+    // size was saved, and is called at the end of this constructor because
+    // the header state cannot be restored before the columns exist.
     resize(760, 520);
 
     m_rules.load();
@@ -244,6 +253,72 @@ TagRulesDialog::TagRulesDialog(QWidget *parent)
 
     reloadList();
     showWarnings();
+
+    // Last, and after reloadList(): a header state cannot be applied before
+    // the columns it describes exist, and reloadList is what fills them.
+    restoreUiState();
+}
+
+/// Reads the window size and the rule list's header layout back.
+///
+/// The same file MainWindow uses, under keys of its own. Machine-written
+/// state, never the hand-edited config: a column width is not something
+/// anyone edits by hand, and mixing the two puts a blob in a file the user
+/// reads.
+void TagRulesDialog::restoreUiState()
+{
+    QSettings state(MainWindow::uiStatePath(), QSettings::IniFormat);
+
+    const QByteArray geometry =
+        state.value(QStringLiteral("tagrules/geometry")).toByteArray();
+    if (!geometry.isEmpty())
+        restoreGeometry(geometry);
+
+    const QByteArray header =
+        state.value(QStringLiteral("tagrules/header")).toByteArray();
+    if (!header.isEmpty()) {
+        m_list->header()->restoreState(header);
+        // Counts as the one auto-size each column gets, so the restore is not
+        // immediately overwritten. reloadList() runs before this in the
+        // constructor and has already sized the first two; the count column
+        // has not been filled yet, and would otherwise resize over the
+        // restored width as soon as the first counts arrived.
+        m_columnsSized = true;
+        m_countColumnSized = true;
+    }
+}
+
+void TagRulesDialog::saveUiState()
+{
+    QDir().mkpath(QFileInfo(MainWindow::uiStatePath()).absolutePath());
+    QSettings state(MainWindow::uiStatePath(), QSettings::IniFormat);
+    state.setValue(QStringLiteral("tagrules/geometry"), saveGeometry());
+    state.setValue(QStringLiteral("tagrules/header"),
+                   m_list->header()->saveState());
+}
+
+/// Saves on close rather than on accept, so a size the user chose is kept
+/// whether they pressed Save or Cancel. The window's shape is not part of the
+/// edit being confirmed.
+void TagRulesDialog::closeEvent(QCloseEvent *event)
+{
+    saveUiState();
+    QDialog::closeEvent(event);
+}
+
+int TagRulesDialog::columnWidthForTest(int column) const
+{
+    return m_list->columnWidth(column);
+}
+
+void TagRulesDialog::setColumnWidthForTest(int column, int width)
+{
+    m_list->setColumnWidth(column, width);
+}
+
+void TagRulesDialog::reloadListForTest()
+{
+    reloadList();
 }
 
 void TagRulesDialog::showWarnings()
@@ -286,8 +361,15 @@ void TagRulesDialog::reloadList()
         auto *item = new QTreeWidgetItem(m_list);
         fillItem(item, rule);
     }
-    m_list->resizeColumnToContents(ColumnEnabled);
-    m_list->resizeColumnToContents(ColumnStage);
+    // Auto-sized on the FIRST fill only. After that the widths belong to the
+    // user, whether they came from a restored header or from a drag in this
+    // session, and resizing on every repopulate threw both away on the next
+    // add or delete.
+    if (!m_columnsSized) {
+        m_list->resizeColumnToContents(ColumnEnabled);
+        m_list->resizeColumnToContents(ColumnStage);
+        m_columnsSized = true;
+    }
     m_reloading = false;
 
     if (!m_working.isEmpty())
@@ -439,7 +521,12 @@ void TagRulesDialog::setCounts(const QVector<int> &counts)
             counts.at(i) < 0 ? tr("invalid")
                              : QString::number(counts.at(i)));
     }
-    m_list->resizeColumnToContents(ColumnCount);
+    // Once, like the columns in reloadList. The counts arrive after the first
+    // fill, so this column gets its own flag rather than sharing that one.
+    if (!m_countColumnSized) {
+        m_list->resizeColumnToContents(ColumnCount);
+        m_countColumnSized = true;
+    }
 }
 
 void TagRulesDialog::onSave()
diff --git a/src/tagrulesdialog.h b/src/tagrulesdialog.h
index 9559918..f86d210 100644
--- a/src/tagrulesdialog.h
+++ b/src/tagrulesdialog.h
@@ -56,9 +56,14 @@ public:
     /// handle and notmuch permits one per process.
     QStringList countQueries() const;
 
-    /// Account subdirectory names, for the Folder row's dropdown. Supplied by
-    /// the caller rather than read here: Config knows them, and this dialog
-    /// deliberately holds no Config of its own.
+    /// Maildir folder paths, for the Folder row's dropdown, relative to the
+    /// database root. Supplied by the caller rather than read here: they come
+    /// from a scan of the tree under notmuch's database.path, which only
+    /// NotmuchWorker can answer for, and this dialog reaches neither it nor
+    /// Config.
+    ///
+    /// Arrives AFTER the dialog is on screen, since the scan crosses to the
+    /// worker on a queued call, so this refills the rows that already exist.
     void setFolders(const QStringList &folders);
 
     /// Test seams. The builder's state is otherwise reachable only through
@@ -88,6 +93,20 @@ public:
     /// when the widget is not.
     bool textModeToggleIsReachableForTest() const;
 
+    /// Width of one rule-list column. The geometry restore is asserted on the
+    /// saved and reread VALUE rather than on the resulting frame: item 46
+    /// records that the offscreen platform does not honour a window resize,
+    /// so a test comparing frames there passes or fails for reasons that have
+    /// nothing to do with the code.
+    int columnWidthForTest(int column) const;
+    void setColumnWidthForTest(int column, int width);
+
+    /// Repopulates the rule list, as adding or deleting a rule does. Exposed
+    /// because a restored column width has to survive one of these, not only
+    /// a close and reopen: `resizeColumnToContents` on every reload discarded
+    /// the width the user had dragged.
+    void reloadListForTest();
+
 signals:
     /// Asks the owner to run countQueries() through the worker.
     void countsRequested();
@@ -104,8 +123,13 @@ private slots:
     void applyEditsToCurrentRule();
     void onSave();
 
+protected:
+    void closeEvent(QCloseEvent *event) override;
+
 private:
     void reloadList();
+    void restoreUiState();
+    void saveUiState();
     void showWarnings();
     int currentIndex() const;
 
@@ -160,6 +184,15 @@ private:
     /// row's text, which applyEditsToCurrentRule() has no chance to flush.
     bool m_reloading = false;
 
+    /// Each column is auto-sized to its contents ONCE, on its first fill.
+    /// After that its width belongs to the user, whether it came from a
+    /// restored header or from a drag, and resizeColumnToContents on every
+    /// repopulate threw both away on the next add or delete. Two flags rather
+    /// than one because the count column is filled later than the rest, by a
+    /// reply from the worker.
+    bool m_columnsSized = false;
+    bool m_countColumnSized = false;
+
     QTreeWidget *m_list = nullptr;
     QLineEdit *m_id = nullptr;
     QLineEdit *m_add = nullptr;