From 5ba93619fae4eedca092bd7e4551b9034d725ff4 Mon Sep 17 00:00:00 2001
From: Yuri Roubinsky <chaosus89@gmail.com>
Date: Tue, 30 Nov 2021 23:28:35 +0300
Subject: [PATCH] Allow using empty statements in the shader, added formatting
 warning

---
 drivers/gles3/shader_compiler_gles3.cpp        |  4 ++++
 .../renderer_rd/shader_compiler_rd.cpp         |  3 +++
 servers/rendering/shader_language.cpp          | 18 +++++++++++++++---
 servers/rendering/shader_language.h            |  1 +
 servers/rendering/shader_warnings.cpp          |  4 ++++
 servers/rendering/shader_warnings.h            |  2 ++
 tests/servers/test_shader_lang.cpp             |  2 ++
 7 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/drivers/gles3/shader_compiler_gles3.cpp b/drivers/gles3/shader_compiler_gles3.cpp
index f9443e11dbc..168080f2f10 100644
--- a/drivers/gles3/shader_compiler_gles3.cpp
+++ b/drivers/gles3/shader_compiler_gles3.cpp
@@ -758,6 +758,10 @@ String ShaderCompilerGLES3::_dump_node_code(SL::Node *p_node, int p_level, Gener
 					code += a + " - " + n + " * (" + a + " / " + n + "))";
 				} break;
 
+				case SL::OP_EMPTY: {
+					// Semicolon (or empty statement) - ignored.
+				} break;
+
 				default: {
 					if (p_use_scope) {
 						code += "(";
diff --git a/servers/rendering/renderer_rd/shader_compiler_rd.cpp b/servers/rendering/renderer_rd/shader_compiler_rd.cpp
index 77d3a2e7662..b02b3d27232 100644
--- a/servers/rendering/renderer_rd/shader_compiler_rd.cpp
+++ b/servers/rendering/renderer_rd/shader_compiler_rd.cpp
@@ -1318,6 +1318,9 @@ String ShaderCompilerRD::_dump_node_code(const SL::Node *p_node, int p_level, Ge
 					code += ")";
 
 				} break;
+				case SL::OP_EMPTY: {
+					// Semicolon (or empty statement) - ignored.
+				} break;
 
 				default: {
 					if (p_use_scope) {
diff --git a/servers/rendering/shader_language.cpp b/servers/rendering/shader_language.cpp
index 8dd939ffd72..7149d386415 100644
--- a/servers/rendering/shader_language.cpp
+++ b/servers/rendering/shader_language.cpp
@@ -5208,9 +5208,21 @@ ShaderLanguage::Node *ShaderLanguage::_parse_expression(BlockNode *p_block, cons
 			expression.push_back(e);
 			continue;
 		} else {
-			_set_error("Expected expression, found: " + get_token_text(tk));
-			return nullptr;
-			//nothing
+			if (tk.type != TK_SEMICOLON) {
+				_set_error("Expected expression, found: " + get_token_text(tk));
+				return nullptr;
+			} else {
+#if DEBUG_ENABLED
+				if (check_warnings && HAS_WARNING(ShaderWarning::FORMATTING_ERROR_FLAG)) {
+					_add_line_warning(ShaderWarning::FORMATTING_ERROR, "Empty statement. Remove ';' to fix this warning.");
+				}
+#endif // DEBUG_ENABLED
+				_set_tkpos(prepos);
+
+				OperatorNode *func = alloc_node<OperatorNode>();
+				func->op = OP_EMPTY;
+				expr = func;
+			}
 		}
 
 		ERR_FAIL_COND_V(!expr, nullptr);
diff --git a/servers/rendering/shader_language.h b/servers/rendering/shader_language.h
index 193e2b72806..3de89a89a55 100644
--- a/servers/rendering/shader_language.h
+++ b/servers/rendering/shader_language.h
@@ -287,6 +287,7 @@ public:
 		OP_CONSTRUCT,
 		OP_STRUCT,
 		OP_INDEX,
+		OP_EMPTY,
 		OP_MAX
 	};
 
diff --git a/servers/rendering/shader_warnings.cpp b/servers/rendering/shader_warnings.cpp
index 0b8476478c9..bffae484a8c 100644
--- a/servers/rendering/shader_warnings.cpp
+++ b/servers/rendering/shader_warnings.cpp
@@ -61,6 +61,8 @@ String ShaderWarning::get_message() const {
 			return vformat("The varying '%s' is declared but never used.", subject);
 		case UNUSED_LOCAL_VARIABLE:
 			return vformat("The local variable '%s' is declared but never used.", subject);
+		case FORMATTING_ERROR:
+			return subject;
 		default:
 			break;
 	}
@@ -82,6 +84,7 @@ String ShaderWarning::get_name_from_code(Code p_code) {
 		"UNUSED_UNIFORM",
 		"UNUSED_VARYING",
 		"UNUSED_LOCAL_VARIABLE",
+		"FORMATTING_ERROR",
 	};
 
 	static_assert((sizeof(names) / sizeof(*names)) == WARNING_MAX, "Amount of warning types don't match the amount of warning names.");
@@ -110,6 +113,7 @@ static void init_code_to_flags_map() {
 	code_to_flags_map->insert(ShaderWarning::UNUSED_UNIFORM, ShaderWarning::UNUSED_UNIFORM_FLAG);
 	code_to_flags_map->insert(ShaderWarning::UNUSED_VARYING, ShaderWarning::UNUSED_VARYING_FLAG);
 	code_to_flags_map->insert(ShaderWarning::UNUSED_LOCAL_VARIABLE, ShaderWarning::UNUSED_LOCAL_VARIABLE_FLAG);
+	code_to_flags_map->insert(ShaderWarning::FORMATTING_ERROR, ShaderWarning::FORMATTING_ERROR_FLAG);
 }
 
 ShaderWarning::CodeFlags ShaderWarning::get_flags_from_codemap(const Map<Code, bool> &p_map) {
diff --git a/servers/rendering/shader_warnings.h b/servers/rendering/shader_warnings.h
index db872d8fb14..18915fffd88 100644
--- a/servers/rendering/shader_warnings.h
+++ b/servers/rendering/shader_warnings.h
@@ -47,6 +47,7 @@ public:
 		UNUSED_UNIFORM,
 		UNUSED_VARYING,
 		UNUSED_LOCAL_VARIABLE,
+		FORMATTING_ERROR,
 		WARNING_MAX,
 	};
 
@@ -59,6 +60,7 @@ public:
 		UNUSED_UNIFORM_FLAG = 16U,
 		UNUSED_VARYING_FLAG = 32U,
 		UNUSED_LOCAL_VARIABLE_FLAG = 64U,
+		FORMATTING_ERROR_FLAG = 128U,
 	};
 
 private:
diff --git a/tests/servers/test_shader_lang.cpp b/tests/servers/test_shader_lang.cpp
index 0591bf6adff..f4a32c67231 100644
--- a/tests/servers/test_shader_lang.cpp
+++ b/tests/servers/test_shader_lang.cpp
@@ -261,6 +261,8 @@ static String dump_node_code(SL::Node *p_node, int p_level) {
 					}
 					code += ")";
 					break;
+				case SL::OP_EMPTY:
+					break;
 				default: {
 					code = "(" + dump_node_code(onode->arguments[0], p_level) + _opstr(onode->op) + dump_node_code(onode->arguments[1], p_level) + ")";
 					break;