Dynamically obtain line number of panic! expression

Author: Bromeon

godot-core/src/private.rs

@@ -390,7 +390,7 @@ where
                 let msg = extract_panic_message(err);
                 let mut msg = format_panic_message(msg);
 
-                // try to add location information
+                // Try to add location information.
                 if let Ok(guard) = info.lock() {
                     if let Some(info) = guard.as_ref() {
                         msg = format!("{}\n  at {}:{}", msg, info.file, info.line);

itest/rust/src/object_tests/dynamic_call_test.rs

@@ -154,11 +154,14 @@ fn dynamic_call_with_panic() {
     #[cfg(not(target_os = "windows"))]
     let path = "itest/rust/src/object_tests/object_test.rs";
 
+    // Obtain line number dynamically, avoids tedious maintenance on code reorganization.
+    let line = ObjPayload::get_panic_line();
+
     let expected_error_message = format!(
         "godot-rust function call failed: Object::call(&\"do_panic\")\
         \n  Source: ObjPayload::do_panic()\
         \n    Reason: [panic]  do_panic exploded\
-        \n  at {path}:893"
+        \n  at {path}:{line}"
     );
 
     assert_eq!(call_error.to_string(), expected_error_message);

itest/rust/src/object_tests/object_test.rs

@@ -887,6 +887,11 @@ impl ObjPayload {
     fn do_panic(&self) {
         panic!("do_panic exploded");
     }
+
+    // Obtain the line number of the panic!() call above; keep equidistant to do_panic() method.
+    pub fn get_panic_line() -> u32 {
+        line!() - 5
+    }
 }
 
 // ----------------------------------------------------------------------------------------------------------------------------------------------