[Fix, Test] (MG_Backend/DirectGLES): hand every compiled shader's lifetime to its program - glDeleteShader was never called, so each program build leaked its driver shader objects

MobileGL/MG_Backend/DirectGLES/Managers.cpp

@@ -4386,11 +4386,28 @@ namespace MobileGL::MG_Backend::DirectGLES {
                     log.back() = '\0';
                     MGLOG_E("Shader compilation failed for backend ID %u: %s", backendShaderId, log.data());
                     m_backendProgramUsable = false;
+                    // Nothing will ever attach this one, so nothing else can free it.
+                    g_GLESFuncs.glDeleteShader(backendShaderId);
                     continue;
                 }
 
                 MGLOG_D("Attaching shader ID: %u to program %u", backendShaderId, m_backendProgramId);
                 g_GLESFuncs.glAttachShader(m_backendProgramId, backendShaderId);
+                // Hand the shader's lifetime to the program, immediately and unconditionally.
+                //
+                // glDeleteShader only FLAGS a shader; the driver frees it when it is attached to
+                // nothing. Flagging it here is what makes the program own it, so deleting the
+                // program (or the detach loop above, on a relink) is what actually frees it.
+                // Without this call every program build leaked its shader objects for the process
+                // lifetime, and a relink leaked them twice - the detach loop above dropped the
+                // program's reference to shaders nothing had flagged, so they became unreachable
+                // AND undeletable. The GL swizzle conformance test builds 1,296 programs per case,
+                // so a handful of cases left tens of thousands of live driver shaders behind and
+                // the driver started mis-serving them (KHR-GL33/GL40.texture_swizzle.smoke_*).
+                // Same class of defect as the missing framebuffer/renderbuffer/sampler destructors
+                // fixed in Wave 1, and the last of that family: this is the one backend GL object
+                // MobileGL creates without an owning wrapper to destroy it.
+                g_GLESFuncs.glDeleteShader(backendShaderId);
 
                 MGLOG_D("Processed shader source length: %zu", source.length());
             }

MobileGL/MG_IntegrationTest/Scenarios/SwizzleAccessRoutineScenario.cpp

@@ -247,6 +247,49 @@ void main()
         Gl().EndFrame();
     }
 
+    // Program churn: the shape that made the conformance suite fail, reduced.
+    //
+    // The swizzle smoke test builds one program per swizzle combination - 1,296 per case - and
+    // DirectGLES created a driver shader object per attached shader without ever calling
+    // glDeleteShader. glDeleteShader only FLAGS a shader for deletion (the driver frees it once
+    // nothing has it attached), so without that call the program's own deletion could not free
+    // them either: eight cases left ~20,000 live driver shaders behind, the Adreno ES driver
+    // passed its ceiling, and it began mis-serving shaders - first the sampling variants with the
+    // most image operands (textureLod/texelFetch/*Offset), while plain texture/textureGrad still
+    // worked. On device this loop plus a value check is the whole defect.
+    //
+    // HONEST LIMIT OF THIS TEST: llvmpipe has no such ceiling, so this passes here whether or not
+    // the leak is present - it cannot fail on the CI lane. It is a standing guard for the SHAPE
+    // (build many programs, keep reading the right texel) and the place to raise the iteration
+    // count if a driver ceiling ever needs reproducing; the leak itself is pinned by device
+    // measurement (VmRSS flat at ~137 MB across the 32-case family, against 132 -> 154 MB and
+    // still climbing before the fix).
+    TEST_F(SwizzleAccessRoutineScenario, RepeatedProgramBuildsKeepFetchingTheSameTexel) {
+        if (!Ready() || IsSkipped()) return;
+        SetSwizzle(GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA);
+        ASSERT_EQ(FirstGLError(), 0u);
+
+        // One routine from each side of the device's failure order, so a ceiling that takes the
+        // vulnerable one down first is still caught.
+        const AccessRoutine& plain = kRoutines[0];      // texture
+        const AccessRoutine& explicitLod = kRoutines[1]; // textureLod
+        constexpr int kIterations = 200;
+
+        for (int i = 0; i < kIterations; ++i) {
+            const AccessRoutine& routine = (i % 2 == 0) ? plain : explicitLod;
+            const int channel = i % 4;
+            const std::vector<std::uint32_t> texels = Render(routine, channel);
+            if (::testing::Test::HasFailure()) return; // a build failure repeats 200 times; say it once
+            ExpectAllTexels(routine, channel, kSourceTexel[channel], texels);
+            if (::testing::Test::HasFailure()) {
+                ADD_FAILURE() << "diverged at iteration " << i << " of " << kIterations;
+                return;
+            }
+        }
+        EXPECT_EQ(FirstGLError(), 0u) << "the churn loop left a GL error behind";
+        Gl().EndFrame();
+    }
+
     // GL_ONE and GL_ZERO, which the conformance table spells as the literal values 1 and 0 and
     // which the backend has to synthesise rather than fetch.
     TEST_F(SwizzleAccessRoutineScenario, EveryAccessRoutineSeesConstantSwizzleSources) {