Add knowledge file for raising events inside try functions (#31)

community/knowledge/events/avoid-raising-events-inside-try-functions.bad.al

@@ -0,0 +1,38 @@
+// Demonstration only. Shows the wrong pattern: raising the integration event inside a TryFunction body.
+
+codeunit 50116 "Payment Processor Bad"
+{
+    [IntegrationEvent(false, false)]
+    procedure OnBeforeSubmitPayment(var PaymentAmount: Decimal; var Cancel: Boolean)
+    begin
+    end;
+
+    procedure SubmitPayment(PaymentAmount: Decimal)
+    var
+        Success: Boolean;
+    begin
+        // TryFunction wraps both the event raise and the gateway call.
+        Success := TrySubmitPaymentInternal(PaymentAmount);
+        if not Success then
+            Error('Payment gateway call failed. Check connectivity and retry.');
+    end;
+
+    [TryFunction]
+    local procedure TrySubmitPaymentInternal(PaymentAmount: Decimal)
+    var
+        Cancel: Boolean;
+        Client: HttpClient;
+        Response: HttpResponseMessage;
+    begin
+        Cancel := false;
+        // BAD: event raised inside TryFunction. Any Error() thrown by a subscriber is caught here
+        // and silently swallowed - the subscriber's error never reaches the caller.
+        // A subscriber setting Cancel := true is also lost when TryFunction returns false.
+        OnBeforeSubmitPayment(PaymentAmount, Cancel);
+        if Cancel then
+            exit;
+        Client.Get('https://payments.example.com/submit?amount=' + Format(PaymentAmount), Response);
+        if not Response.IsSuccessStatusCode() then
+            Error('HTTP %1', Response.HttpStatusCode());
+    end;
+}