feat(ui): give the message pane its own action bar

Items 139, 140 and 141, built together because the seam between them is
wasted work: 140 needs a container and 141 is that container.

The main toolbar had grown to mix two scopes. Sync, Archive, Delete, Mark
all read and Undo act on the list or the selection; Compose, Reply and
Forward are about one message. With everything in one row the distinction
was invisible, and Forward was on no toolbar at all, reachable only from the
Message menu, which is item 139.

Compose, Reply and Forward now sit on a bar above the message pane, and
LEAVE the main toolbar rather than gaining a second home: that is what makes
the toolbar's remaining contents mean one thing. Toggle HTML joins them at
the right end, separated by an expanding spacer, since changing how a
message is displayed is a different scope from acting on it. That layout was
the open design question item 141 recorded, and it was settled with the user
rather than guessed.

The actions are MainWindow's own QAction objects shown a second time, never
copies: a duplicate would carry its own enablement and drift from the menu
entry updateComposeActions() keeps in step. MessageView::setBarActions() is
the seam, so the pane still knows nothing about the window's action map.

Two things worth recording:

QToolBar has no addStretch(), so the separation is an expanding spacer
widget. A test asserting only on action ORDER passes with that spacer
deleted, measured, so it asserts on the spacer's size policy instead.

noTwoActionsShareAnIcon looked up the toolbar with an unnamed
findChild<QToolBar*>(). There are two toolbars now, so it is pinned to
main_toolbar: pointed at the pane's bar it would have asserted that a
thread action is absent from a bar that never holds any, and passed while
the rule it exists for went unchecked.

1 files changed, 19 insertions, 9 deletions

diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index 9a94a2e..fd59f47 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -555,6 +555,9 @@ MainWindow::MainWindow(const Config &config, QWidget *parent)
     }
 
     buildMenus();
+    // After buildMenus(), which registers the toolbar and menu entries these
+    // actions already carry: the bar shows the same objects a second time.
+    populateMessageBar();
     // After buildMenus(): QMainWindow::restoreState() matches toolbars by
     // object name, so they must already exist or their position is dropped.
     restoreUiState();
@@ -1967,15 +1970,10 @@ void MainWindow::buildMenus()
     const int iconSize = m_config.toolbarIconSize();
     toolBar->setIconSize(QSize(iconSize, iconSize));
 
-    // First, because composing and replying are what a user reaches for most
-    // (item 123). These TWO only: the other four are menu-and-key, which is
-    // what keeps the no-duplicate-icons rule satisfiable, since reply_no_quote
-    // shares reply's icon and an icon-only toolbar would make the two buttons
-    // indistinguishable.
-    toolBar->addAction(m_actions.value(QStringLiteral("compose")));
-    toolBar->addAction(m_actions.value(QStringLiteral("reply")));
-    toolBar->addSeparator();
-
+    // Compose, Reply and Forward are NOT here (item 140). They act on a
+    // message, where everything below acts on the list or on the selection,
+    // and mixing the two is what made this toolbar read as the place for
+    // everything. They live on the message pane's own bar instead.
     QAction *syncAction = m_actions.value(QStringLiteral("sync"));
     // Carried over from the QPushButton this replaced: with no command
     // configured the control is disabled, and the tooltip is the only thing
@@ -1994,6 +1992,18 @@ void MainWindow::buildMenus()
     toolBar->addAction(m_actions.value(QStringLiteral("undo")));
 }
 
+void MainWindow::populateMessageBar()
+{
+    // The window's own QActions, shown a second time rather than copied: a
+    // duplicate QAction would need its own enablement and would drift from the
+    // menu entry that updateComposeActions() keeps in step.
+    m_messageView->setBarActions(
+        { m_actions.value(QStringLiteral("compose")),
+          m_actions.value(QStringLiteral("reply")),
+          m_actions.value(QStringLiteral("forward")) },
+        { m_actions.value(QStringLiteral("toggle_html")) });
+}
+
 void MainWindow::showShortcutReference()
 {
     // Generated from the actions, so it cannot disagree with what the keys