From bebe534bad1f2e061c1b9065163b8d2018785ca2 Mon Sep 17 00:00:00 2001
From: Swung0x48 <swung0x48@outlook.com>
Date: Sat, 11 Jul 2026 00:19:33 -0400
Subject: [PATCH] [Fix] (MG_Impl/GLImpl): stop double-recording GL errors for a
 bad program handle

glBindFragDataLocation, glGetFragDataLocation and glGetFragDataIndex each
recorded a redundant GL_INVALID_OPERATION on top of the error that
TryToGetProgramObject already recorded (GL_INVALID_VALUE for an unknown
name, GL_INVALID_OPERATION for a non-program object). One bad call thus
queued two errors, so an app calling glGetError twice saw a spurious
second error, and any following code that expects a clean error queue
(e.g. a later test) picked up the stale one.

Drop the second RecordError from all three call sites and rely on the
single error TryToGetProgramObject already reports -- matching the clean
`if (!programObject) return;` pattern the rest of GL_Program.cpp uses. The
first, app-visible error is unchanged; only the redundant second is gone.

ProgramTest's invalid-handle case now asserts exactly one error (mutation-
verified: reintroducing the second record fails it) and keeps a defensive
error-queue drain. ProgramTest 24/24.
---
 .../MG_Impl/GLImpl/Program/GL_Program.cpp     | 26 ++++---------------
 MobileGL/MG_Test/Program/ProgramTest.cpp      |  6 +++--
 2 files changed, 9 insertions(+), 23 deletions(-)

diff --git a/MobileGL/MG_Impl/GLImpl/Program/GL_Program.cpp b/MobileGL/MG_Impl/GLImpl/Program/GL_Program.cpp
index 9fb0fcf5..c4b40dde 100644
--- a/MobileGL/MG_Impl/GLImpl/Program/GL_Program.cpp
+++ b/MobileGL/MG_Impl/GLImpl/Program/GL_Program.cpp
@@ -1485,13 +1485,9 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void BindFragDataLocation_State(GLuint program, GLuint colorNumber, const char* name) {
         auto& programObject = TryToGetProgramObject(program);
-        if (programObject == nullptr) {
-            MG_State::pGLContext->RecordError(
-                ErrorCode::InvalidOperation,
-                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
-                                             std::to_string(program) + " is not the name of a program object."));
-            return;
-        }
+        // TryToGetProgramObject already recorded the error for a bad handle (GL_INVALID_VALUE for an
+        // unknown name, GL_INVALID_OPERATION for a non-program object); do not record a second one.
+        if (!programObject) return;
         if (name == nullptr) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
@@ -1520,13 +1516,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     GLint GetFragDataLocation_State(GLuint program, const char* name) {
         auto& programObject = TryToGetProgramObject(program);
-        if (programObject == nullptr) {
-            MG_State::pGLContext->RecordError(
-                ErrorCode::InvalidOperation,
-                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
-                                             std::to_string(program) + " is not the name of a program object."));
-            return -1;
-        }
+        if (!programObject) return -1; // TryToGetProgramObject already recorded the error.
         if (name == nullptr) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
@@ -1545,13 +1535,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     GLint GetFragDataIndex_State(GLuint program, const char* name) {
         auto& programObject = TryToGetProgramObject(program);
-        if (programObject == nullptr) {
-            MG_State::pGLContext->RecordError(
-                ErrorCode::InvalidOperation,
-                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
-                                             std::to_string(program) + " is not the name of a program object."));
-            return -1;
-        }
+        if (!programObject) return -1; // TryToGetProgramObject already recorded the error.
         if (name == nullptr) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
diff --git a/MobileGL/MG_Test/Program/ProgramTest.cpp b/MobileGL/MG_Test/Program/ProgramTest.cpp
index 8efc4950..15200bac 100644
--- a/MobileGL/MG_Test/Program/ProgramTest.cpp
+++ b/MobileGL/MG_Test/Program/ProgramTest.cpp
@@ -1564,8 +1564,10 @@ TEST_F(ProgramTest, GetFragDataIndexRejectsInvalidProgram) {
     // routes through the shared program-name check, which records GL_INVALID_VALUE for an unknown name.
     EXPECT_EQ(GetFragDataIndex(999999u, "fragColor"), -1);
     EXPECT_EQ(GetError(), GL_INVALID_VALUE);
-    // The name check and the entry point each queue an error for an unknown handle; drain the rest so
-    // no stale error leaks into a later test (the fixture does not reset the error queue).
+    // Exactly ONE error is recorded per bad call: the redundant second GL_INVALID_OPERATION that the
+    // FragData entry points used to queue on top of the name check has been removed.
+    EXPECT_EQ(GetError(), GL_NO_ERROR);
+    // Defensive drain: keep the shared error queue clean regardless (the fixture never resets it).
     while (GetError() != GL_NO_ERROR) {}
 }