Defer speed-dial web commands off the webview callback stack

src/slic3r/GUI/SpeedDialDialog.cpp

@@ -55,6 +55,8 @@ SpeedDialWebDialog::SpeedDialWebDialog(wxWindow* parent)
     }
 }
 
+SpeedDialWebDialog::~SpeedDialWebDialog() { m_alive->store(false, std::memory_order_release); }
+
 void SpeedDialWebDialog::request_show()
 {
     if (IsShown()) {
@@ -77,6 +79,18 @@ void SpeedDialWebDialog::on_script_message(const nlohmann::json& payload)
     if (handle_common_script_command(payload))
         return;
 
+    // Defer command handling out of the webview script-message callback: GTK and macOS deliver
+    // it synchronously inside the native webview callback, and window work on that stack is the
+    // crash class fixed in b779a7bfed/f2ccbfc8b5 (see PluginsDialog::on_script_message).
+    // run_action puts a modal confirm on that stack, which is the same bug.
+    wxGetApp().CallAfter([this, alive = m_alive, payload]() {
+        if (alive->load(std::memory_order_acquire))
+            handle_web_command(payload);
+    });
+}
+
+void SpeedDialWebDialog::handle_web_command(const nlohmann::json& payload)
+{
     const std::string command = payload.value("command", "");
     if (command == "request_actions") {
         m_page_ready = true;

src/slic3r/GUI/SpeedDialDialog.hpp

@@ -3,6 +3,8 @@
 
 #include <slic3r/GUI/Widgets/WebViewHostDialog.hpp>
 #include <nlohmann/json_fwd.hpp>
+#include <atomic>
+#include <memory>
 #include <string>
 
 namespace Slic3r { namespace GUI {
@@ -11,15 +13,20 @@ class SpeedDialWebDialog : public WebViewHostDialog
 {
 public:
     explicit SpeedDialWebDialog(wxWindow* parent);
+    ~SpeedDialWebDialog() override;
     void request_show();
 
 private:
     void on_script_message(const nlohmann::json& payload) override;
+    void handle_web_command(const nlohmann::json& payload);
     void resize_to_content(int height);
     void run_action(const std::string& id, const std::string& title);
     void send_actions();
 
     bool m_page_ready{false};
+    // Guards the CallAfter in on_script_message across dialog destruction, same as
+    // PluginsDialog::m_alive (PluginsDialog.hpp:249).
+    std::shared_ptr<std::atomic<bool>> m_alive = std::make_shared<std::atomic<bool>>(true);
 };
 
 }}