From e270d1cce34936a1ca65da93107b0ec07a040539 Mon Sep 17 00:00:00 2001
From: Yuri Roubinsky <chaosus89@gmail.com>
Date: Sun, 10 Oct 2021 22:22:07 +0300
Subject: [PATCH] Fix autocompletion of built-in functions in GDScript

---
 core/variant/variant.h               |  1 +
 core/variant/variant_utility.cpp     | 22 ++++++++++++++++++++++
 modules/gdscript/gdscript_editor.cpp | 15 ++++++++++++++-
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/core/variant/variant.h b/core/variant/variant.h
index 9ec131a1b8..d3f694e7ca 100644
--- a/core/variant/variant.h
+++ b/core/variant/variant.h
@@ -641,6 +641,7 @@ public:
 
 	static UtilityFunctionType get_utility_function_type(const StringName &p_name);
 
+	static MethodInfo get_utility_function_info(const StringName &p_name);
 	static int get_utility_function_argument_count(const StringName &p_name);
 	static Variant::Type get_utility_function_argument_type(const StringName &p_name, int p_arg);
 	static String get_utility_function_argument_name(const StringName &p_name, int p_arg);
diff --git a/core/variant/variant_utility.cpp b/core/variant/variant_utility.cpp
index 55c1376031..666b582e39 100644
--- a/core/variant/variant_utility.cpp
+++ b/core/variant/variant_utility.cpp
@@ -1333,6 +1333,28 @@ Variant::UtilityFunctionType Variant::get_utility_function_type(const StringName
 	return bfi->type;
 }
 
+MethodInfo Variant::get_utility_function_info(const StringName &p_name) {
+	MethodInfo info;
+	const VariantUtilityFunctionInfo *bfi = utility_function_table.lookup_ptr(p_name);
+	if (bfi) {
+		info.name = p_name;
+		if (bfi->returns_value && bfi->return_type == Variant::NIL) {
+			info.return_val.usage |= PROPERTY_USAGE_NIL_IS_VARIANT;
+		}
+		info.return_val.type = bfi->return_type;
+		if (bfi->is_vararg) {
+			info.flags |= METHOD_FLAG_VARARG;
+		}
+		for (int i = 0; i < bfi->argnames.size(); ++i) {
+			PropertyInfo arg;
+			arg.type = bfi->get_arg_type(i);
+			arg.name = bfi->argnames[i];
+			info.arguments.push_back(arg);
+		}
+	}
+	return info;
+}
+
 int Variant::get_utility_function_argument_count(const StringName &p_name) {
 	const VariantUtilityFunctionInfo *bfi = utility_function_table.lookup_ptr(p_name);
 	if (!bfi) {
diff --git a/modules/gdscript/gdscript_editor.cpp b/modules/gdscript/gdscript_editor.cpp
index e49bf518a2..71d2699c2e 100644
--- a/modules/gdscript/gdscript_editor.cpp
+++ b/modules/gdscript/gdscript_editor.cpp
@@ -1089,6 +1089,15 @@ static void _find_identifiers(GDScriptParser::CompletionContext &p_context, bool
 		kwa++;
 	}
 
+	List<StringName> utility_func_names;
+	Variant::get_utility_function_list(&utility_func_names);
+
+	for (List<StringName>::Element *E = utility_func_names.front(); E; E = E->next()) {
+		ScriptCodeCompletionOption option(E->get(), ScriptCodeCompletionOption::KIND_FUNCTION);
+		option.insert_text += "(";
+		r_result.insert(option.display, option);
+	}
+
 	OrderedHashMap<StringName, ProjectSettings::AutoloadInfo> autoloads = ProjectSettings::get_singleton()->get_autoload_list();
 	for (OrderedHashMap<StringName, ProjectSettings::AutoloadInfo>::Element E = autoloads.front(); E; E = E.next()) {
 		if (!E.value().is_singleton) {
@@ -2325,7 +2334,11 @@ static void _find_call_arguments(GDScriptParser::CompletionContext &p_context, c
 
 	GDScriptCompletionIdentifier connect_base;
 
-	if (GDScriptUtilityFunctions::function_exists(call->function_name)) {
+	if (Variant::has_utility_function(call->function_name)) {
+		MethodInfo info = Variant::get_utility_function_info(call->function_name);
+		r_arghint = _make_arguments_hint(info, p_argidx);
+		return;
+	} else if (GDScriptUtilityFunctions::function_exists(call->function_name)) {
 		MethodInfo info = GDScriptUtilityFunctions::get_function_info(call->function_name);
 		r_arghint = _make_arguments_hint(info, p_argidx);
 		return;