added safe assert fatal errors

deltachat-ios/Helper/Errors.swift

@@ -0,0 +1,23 @@
+import Foundation
+
+/// assertion that is only checked in debug mode (if directly built from Xcode)
+func safe_assert(_ condition: Bool, _ message: String? = nil) {
+    #if DEBUG
+    if let message = message {
+        assert(condition, message)
+    } else {
+        assert(condition)
+    }
+    #endif
+}
+
+/// induces app crash only in debug mode (if directly built from Xcode)
+func safe_fatalError(_ message: String? = nil) {
+    #if DEBUG
+    if let message = message {
+        fatalError(message)
+    } else {
+        fatalError()
+    }
+    #endif
+}