From 857adad2932e56d9f657c96f5ce8377cf69e31c8 Mon Sep 17 00:00:00 2001
From: Kris Austin <kris.austin@gmail.com>
Date: Wed, 22 Jul 2026 13:14:49 -0500
Subject: [PATCH] fix: startup crash on macOS when a printer has a print host
 set (#14747)

---
 src/slic3r/GUI/PrinterWebView.cpp  |  5 ++++-
 src/slic3r/GUI/Widgets/WebView.cpp | 20 ++++++++++++++++++++
 src/slic3r/GUI/Widgets/WebView.hpp |  3 +++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/slic3r/GUI/PrinterWebView.cpp b/src/slic3r/GUI/PrinterWebView.cpp
index 0d6c0bcedf..791bec42b9 100644
--- a/src/slic3r/GUI/PrinterWebView.cpp
+++ b/src/slic3r/GUI/PrinterWebView.cpp
@@ -246,7 +246,10 @@ void PrinterWebView::SendAPIKey()
     // RemoveAllUserScripts causes WebView to forget about our script message handler, 
     // so re-add it here.
     m_browser->RemoveScriptMessageHandler("wx");
-    m_browser->AddScriptMessageHandler("wx");
+    if (m_browser->AddScriptMessageHandler("wx"))
+        WebView::MarkScriptMessageHandlerAdded(m_browser);
+    else
+        wxLogError("Could not add script message handler");
 
 #ifdef __linux__
     // Re-inject the vue-resize/WebKitGTK workaround that RemoveAllUserScripts just cleared.
diff --git a/src/slic3r/GUI/Widgets/WebView.cpp b/src/slic3r/GUI/Widgets/WebView.cpp
index 3214f02d9c..36800dcf47 100644
--- a/src/slic3r/GUI/Widgets/WebView.cpp
+++ b/src/slic3r/GUI/Widgets/WebView.cpp
@@ -242,8 +242,15 @@ public:
             g_webviews.erase(iter);
     }
     wxWebView *m_webView;
+    // Guards against registering the "wx" handler twice (a duplicate throws on WKWebView).
+    bool m_script_handler_added = false;
 };
 
+static WebViewRef *webview_ref(wxWebView *webView)
+{
+    return webView ? static_cast<WebViewRef *>(webView->GetRefData()) : nullptr;
+}
+
 wxWebView* WebView::CreateWebView(wxWindow * parent, wxString const & url)
 {
 #if wxUSE_WEBVIEW_EDGE
@@ -304,10 +311,17 @@ wxWebView* WebView::CreateWebView(wxWindow * parent, wxString const & url)
         Slic3r::GUI::WKWebView_setTransparentBackground(wkWebView);
 #endif
         auto addScriptMessageHandler = [] (wxWebView *webView) {
+            // Skip if SendAPIKey() already registered "wx"; a duplicate add throws an
+            // uncatchable NSException on WKWebView, killing the app at startup.
+            WebViewRef *ref = webview_ref(webView);
+            if (ref && ref->m_script_handler_added)
+                return;
             BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << ": begin to add script message handler for wx.";
             Slic3r::GUI::wxGetApp().set_adding_script_handler(true);
             if (!webView->AddScriptMessageHandler("wx"))
                 wxLogError("Could not add script message handler");
+            else if (ref)
+                ref->m_script_handler_added = true;
             Slic3r::GUI::wxGetApp().set_adding_script_handler(false);
             BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << ": finished add script message handler for wx.";
         };
@@ -336,6 +350,12 @@ wxWebView* WebView::CreateWebView(wxWindow * parent, wxString const & url)
     g_webviews.push_back(webView);
     return webView;
 }
+
+void WebView::MarkScriptMessageHandlerAdded(wxWebView * webView)
+{
+    if (WebViewRef *ref = webview_ref(webView))
+        ref->m_script_handler_added = true;
+}
 #if wxUSE_WEBVIEW_EDGE
 bool WebView::CheckWebViewRuntime()
 {
diff --git a/src/slic3r/GUI/Widgets/WebView.hpp b/src/slic3r/GUI/Widgets/WebView.hpp
index d1d5e9471d..69aa88ca4d 100644
--- a/src/slic3r/GUI/Widgets/WebView.hpp
+++ b/src/slic3r/GUI/Widgets/WebView.hpp
@@ -18,6 +18,9 @@ public:
 
     static bool RunScript(wxWebView * webView, wxString const & msg);
 
+    // Marks "wx" as registered so CreateWebView's deferred add skips the duplicate.
+    static void MarkScriptMessageHandlerAdded(wxWebView * webView);
+
     static void RecreateAll();
 };