macOS: check abnormal-command-exit-runtime when process exits (#12393)

<img width="849" height="434" alt="image"
src="https://github.com/user-attachments/assets/81c89d8d-6f0a-4bb9-b942-6734ff616bf9"
/>

macos/Sources/Ghostty/Ghostty.App.swift

@@ -1649,7 +1649,8 @@ extension Ghostty {
                 // We handle this when the window is visible and timetime_ms is greater than 0,
                 // which will rule out exit codes on launch
                 guard surfaceView.window != nil, v.timetime_ms > 0 else { return false }
-                surfaceView.setChildExitedMessage(.init(v))
+                guard let config = (NSApplication.shared.delegate as? AppDelegate)?.ghostty.config else { return false }
+                surfaceView.setChildExitedMessage(.init(v, threshold: config.abnormalCommandExitRuntime))
                 return true
             default:
                 return false

macos/Sources/Ghostty/Ghostty.ChildExitedMessage.swift

@@ -10,14 +10,32 @@ extension Ghostty {
         let text: String
         let level: Level
 
-        init(_ message: ghostty_surface_message_childexited_s) {
+        init(_ message: ghostty_surface_message_childexited_s, threshold abnormalCommandExitRuntime: Duration) {
+            var level: Level
             switch Int(message.exit_code) {
             case Int(EXIT_SUCCESS):
                 level = .success
             default:
                 level = .error
             }
-            text = "Process exited. Press any key to close the terminal."
+            // See: Surface.zig/childExited
+            // If our runtime was below some threshold then we assume that this
+            // was an abnormal exit and we show an error message.
+            if abnormalCommandExitRuntime >= .milliseconds(message.timetime_ms) {
+                level = .error
+                let measure = Measurement.init(value: Double(message.timetime_ms), unit: UnitDuration.milliseconds)
+                let formatter = MeasurementFormatter()
+                if message.timetime_ms > 1000 {
+                    formatter.unitOptions = .naturalScale
+                } else {
+                    formatter.unitOptions = .providedUnit
+                }
+                formatter.locale = .init(identifier: "en_US")
+                text = "Process exited after **`\(formatter.string(from: measure))`**. Press any key to close the terminal."
+            } else {
+                text = "Process exited. Press any key to close the terminal."
+            }
+            self.level = level
         }
     }
 }

macos/Sources/Ghostty/Ghostty.Config.swift

@@ -709,6 +709,16 @@ extension Ghostty {
             return MacShortcuts(rawValue: str) ?? defaultValue
         }
 
+        var abnormalCommandExitRuntime: Duration {
+            let defaultValue: Duration = .milliseconds(250)
+            guard let config = self.config else { return defaultValue }
+            var v: UInt32?
+            let key = "abnormal-command-exit-runtime"
+            guard ghostty_config_get(config, &v, key, UInt(key.lengthOfBytes(using: .utf8))) else { return defaultValue }
+            guard let v else { return defaultValue }
+            return .milliseconds(v)
+        }
+
         var scrollbar: Scrollbar {
             let defaultValue = Scrollbar.system
             guard let config = self.config else { return defaultValue }

macos/Sources/Ghostty/Surface View/ChildExitedMessageBar.swift

@@ -6,8 +6,7 @@ struct ChildExitedMessageBar: View {
 
     var body: some View {
         HStack(spacing: 6) {
-            Text(msg.text)
-                .fontWeight(.medium)
+            Text(message)
                 .lineLimit(1)
                 .truncationMode(.tail)
         }
@@ -28,6 +27,10 @@ struct ChildExitedMessageBar: View {
                 }
         }
     }
+
+    private var message: AttributedString {
+        (try? AttributedString(markdown: msg.text)) ?? AttributedString(msg.text)
+    }
 }
 
 private extension Ghostty.ChildExitedMessage.Level {