GDScript gracefully handle debug functions from separate thread

2 files changed, 26 insertions, 5 deletions

diff --git a/modules/gdscript/doc_classes/@GDScript.xml b/modules/gdscript/doc_classes/@GDScript.xml
index 631ee4d895..5b476cda01 100644
--- a/modules/gdscript/doc_classes/@GDScript.xml
+++ b/modules/gdscript/doc_classes/@GDScript.xml
@@ -98,6 +98,7 @@
 				[codeblock]
 				[{function:bar, line:12, source:res://script.gd}, {function:foo, line:9, source:res://script.gd}, {function:_ready, line:6, source:res://script.gd}]
 				[/codeblock]
+				[b]Note:[/b] Not supported for calling from threads. Instead, this will return an empty array.
 			</description>
 		</method>
 		<method name="inst2dict">
@@ -160,17 +161,24 @@
 		<method name="print_debug" qualifiers="vararg">
 			<return type="void" />
 			<description>
-				Like [method @GlobalScope.print], but prints only when used in debug mode.
+				Like [method @GlobalScope.print], but includes the current stack frame when running with the debugger turned on.
+				Output in the console would look something like this:
+				[codeblock]
+				Test print
+				   At: res://test.gd:15:_process()
+				[/codeblock]
+				[b]Note:[/b] Not supported for calling from threads. Instead of the stack frame, this will print the thread ID.
 			</description>
 		</method>
 		<method name="print_stack">
 			<return type="void" />
 			<description>
-				Prints a stack track at code location, only works when running with debugger turned on.
+				Prints a stack trace at the current code location. Only works when running with debugger turned on.
 				Output in the console would look something like this:
 				[codeblock]
 				Frame 0 - res://test.gd:16 in function '_process'
 				[/codeblock]
+				[b]Note:[/b] Not supported for calling from threads. Instead of the stack trace, this will print the thread ID.
 			</description>
 		</method>
 		<method name="range" qualifiers="vararg">
diff --git a/modules/gdscript/gdscript_utility_functions.cpp b/modules/gdscript/gdscript_utility_functions.cpp
index f1b0079536..e997d3a51e 100644
--- a/modules/gdscript/gdscript_utility_functions.cpp
+++ b/modules/gdscript/gdscript_utility_functions.cpp
@@ -437,9 +437,13 @@ struct GDScriptUtilityFunctionsDefinitions {
 			str += p_args[i]->operator String();
 		}
 
-		ScriptLanguage *script = GDScriptLanguage::get_singleton();
-		if (script->debug_get_stack_level_count() > 0) {
-			str += "\n   At: " + script->debug_get_stack_level_source(0) + ":" + itos(script->debug_get_stack_level_line(0)) + ":" + script->debug_get_stack_level_function(0) + "()";
+		if (Thread::get_caller_id() == Thread::get_main_id()) {
+			ScriptLanguage *script = GDScriptLanguage::get_singleton();
+			if (script->debug_get_stack_level_count() > 0) {
+				str += "\n   At: " + script->debug_get_stack_level_source(0) + ":" + itos(script->debug_get_stack_level_line(0)) + ":" + script->debug_get_stack_level_function(0) + "()";
+			}
+		} else {
+			str += "\n   At: Cannot retrieve debug info outside the main thread. Thread ID: " + itos(Thread::get_caller_id());
 		}
 
 		print_line(str);
@@ -448,15 +452,24 @@ struct GDScriptUtilityFunctionsDefinitions {
 
 	static inline void print_stack(Variant *r_ret, const Variant **p_args, int p_arg_count, Callable::CallError &r_error) {
 		VALIDATE_ARG_COUNT(0);
+		if (Thread::get_caller_id() != Thread::get_main_id()) {
+			print_line("Cannot retrieve debug info outside the main thread. Thread ID: " + itos(Thread::get_caller_id()));
+			return;
+		}
 
 		ScriptLanguage *script = GDScriptLanguage::get_singleton();
 		for (int i = 0; i < script->debug_get_stack_level_count(); i++) {
 			print_line("Frame " + itos(i) + " - " + script->debug_get_stack_level_source(i) + ":" + itos(script->debug_get_stack_level_line(i)) + " in function '" + script->debug_get_stack_level_function(i) + "'");
 		};
+		*r_ret = Variant();
 	}
 
 	static inline void get_stack(Variant *r_ret, const Variant **p_args, int p_arg_count, Callable::CallError &r_error) {
 		VALIDATE_ARG_COUNT(0);
+		if (Thread::get_caller_id() != Thread::get_main_id()) {
+			*r_ret = Array();
+			return;
+		}
 
 		ScriptLanguage *script = GDScriptLanguage::get_singleton();
 		Array ret;