Add a menu action to open C++ source on GitHub in the editor debugger

This helps user find back the source code where the error/warning
was emitted from.

editor/debugger/script_editor_debugger.cpp

@@ -35,6 +35,8 @@
 #include "core/debugger/remote_debugger.h"
 #include "core/io/marshalls.h"
 #include "core/string/ustring.h"
+#include "core/version.h"
+#include "core/version_hash.gen.h"
 #include "editor/debugger/editor_network_profiler.h"
 #include "editor/debugger/editor_performance_profiler.h"
 #include "editor/debugger/editor_profiler.h"
@@ -1371,7 +1373,8 @@ void ScriptEditorDebugger::_error_tree_item_rmb_selected(const Vector2 &p_pos) {
 	item_menu->set_size(Size2(1, 1));
 
 	if (error_tree->is_anything_selected()) {
-		item_menu->add_icon_item(get_theme_icon("ActionCopy", "EditorIcons"), TTR("Copy Error"), 0);
+		item_menu->add_icon_item(get_theme_icon("ActionCopy", "EditorIcons"), TTR("Copy Error"), ACTION_COPY_ERROR);
+		item_menu->add_icon_item(get_theme_icon("Instance", "EditorIcons"), TTR("Open C++ Source on GitHub"), ACTION_OPEN_SOURCE);
 	}
 
 	if (item_menu->get_item_count() > 0) {
@@ -1381,6 +1384,8 @@ void ScriptEditorDebugger::_error_tree_item_rmb_selected(const Vector2 &p_pos) {
 }
 
 void ScriptEditorDebugger::_item_menu_id_pressed(int p_option) {
+	switch (p_option) {
+		case ACTION_COPY_ERROR: {
 			TreeItem *ti = error_tree->get_selected();
 			while (ti->get_parent() != error_tree->get_root()) {
 				ti = ti->get_parent();
@@ -1405,6 +1410,38 @@ void ScriptEditorDebugger::_item_menu_id_pressed(int p_option) {
 			}
 
 			DisplayServer::get_singleton()->clipboard_set(text);
+		} break;
+
+		case ACTION_OPEN_SOURCE: {
+			TreeItem *ti = error_tree->get_selected();
+			while (ti->get_parent() != error_tree->get_root()) {
+				ti = ti->get_parent();
+			}
+
+			// We only need the first child here (C++ source stack trace).
+			TreeItem *ci = ti->get_children();
+			// Parse back the `file:line @ method()` string.
+			const Vector<String> file_line_number = ci->get_text(1).split("@")[0].strip_edges().split(":");
+			ERR_FAIL_COND_MSG(file_line_number.size() < 2, "Incorrect C++ source stack trace file:line format (please report).");
+			const String file = file_line_number[0];
+			const int line_number = file_line_number[1].to_int();
+
+			// Construct a GitHub repository URL and open it in the user's default web browser.
+			if (String(VERSION_HASH).length() >= 1) {
+				// Git commit hash information available; use it for greater accuracy, including for development versions.
+				OS::get_singleton()->shell_open(vformat("https://github.com/godotengine/godot/blob/%s/%s#L%d",
+						VERSION_HASH,
+						file,
+						line_number));
+			} else {
+				// Git commit hash information unavailable; fall back to tagged releases.
+				OS::get_singleton()->shell_open(vformat("https://github.com/godotengine/godot/blob/%s-stable/%s#L%d",
+						VERSION_NUMBER,
+						file,
+						line_number));
+			}
+		} break;
+	}
 }
 
 void ScriptEditorDebugger::_tab_changed(int p_tab) {

editor/debugger/script_editor_debugger.h

@@ -74,6 +74,11 @@ private:
 		PROFILER_SCRIPTS_SERVERS
 	};
 
+	enum Actions {
+		ACTION_COPY_ERROR,
+		ACTION_OPEN_SOURCE,
+	};
+
 	AcceptDialog *msgdialog;
 
 	LineEdit *clicked_ctrl;