From 836ae06d5a9063469d793f6f176e4f69f992df24 Mon Sep 17 00:00:00 2001
From: Corentin Wallez <cwallez@chromium.org>
Date: Mon, 01 Jun 2026 17:31:29 -0700
Subject: [PATCH] [dawn][native] Disallow TransientAttachment for internal usages.

Contrary to additional usages that are strict additions,
TransientAttachment is an opt-in to additional constraints, so it would
have user-visible effects (plus validation for external usages would need
to take into account the potential internal TransientAttachment).

Fixed: 517247333
Change-Id: Ib197ad592433a2c6ee1b2de2e50e734995f3a111
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/311915
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: David Neto <dneto@google.com>
Auto-Submit: Corentin Wallez <cwallez@chromium.org>
---

diff --git a/src/dawn/native/Texture.cpp b/src/dawn/native/Texture.cpp
index 5c734f5..ca23557 100644
--- a/src/dawn/native/Texture.cpp
+++ b/src/dawn/native/Texture.cpp
@@ -759,6 +759,19 @@
             !device->HasFeature(Feature::DawnInternalUsages),
             "The internalUsageDesc is not empty while the dawn-internal-usages feature is not "
             "enabled");
+
+        // Disallow TransientAttachment because it is not an expansion of usages but instead an
+        // additional constraint and would need to have visible effects (for users of the API that
+        // don't have access to the internal usages). Use an allow-list to explicitly opt-in usages
+        // to be allowed as internal usages in the future.
+        constexpr wgpu::TextureUsage kAllowedInternalUsages =
+            wgpu::TextureUsage::CopySrc | wgpu::TextureUsage::CopyDst |
+            wgpu::TextureUsage::TextureBinding | wgpu::TextureUsage::StorageBinding |
+            wgpu::TextureUsage::RenderAttachment;
+        DAWN_INVALID_IF(!IsSubset(internalUsageDesc->internalUsage, kAllowedInternalUsages),
+                        "internalUsage contains %s which are not allowed as internal usages.",
+                        internalUsageDesc->internalUsage & ~kAllowedInternalUsages);
+
         usage |= internalUsageDesc->internalUsage;
     }
 
diff --git a/src/dawn/tests/unittests/validation/InternalUsageValidationTests.cpp b/src/dawn/tests/unittests/validation/InternalUsageValidationTests.cpp
index d37de44..8a32f52 100644
--- a/src/dawn/tests/unittests/validation/InternalUsageValidationTests.cpp
+++ b/src/dawn/tests/unittests/validation/InternalUsageValidationTests.cpp
@@ -108,6 +108,29 @@
     device.CreateTexture(&textureDesc);
 }
 
+// Test that TransientAttachment cannot be passed as internal usage.
+TEST_F(TextureInternalUsageValidationTest, TransientAttachment) {
+    wgpu::TextureDescriptor textureDesc = {};
+    textureDesc.size = {1, 1};
+    textureDesc.format = wgpu::TextureFormat::RGBA8Unorm;
+
+    wgpu::DawnTextureInternalUsageDescriptor internalDesc = {};
+    textureDesc.nextInChain = &internalDesc;
+
+    // Success case: Texture is Render+Transient and Render as internal usage.
+    textureDesc.usage =
+        wgpu::TextureUsage::RenderAttachment | wgpu::TextureUsage::TransientAttachment;
+    internalDesc.internalUsage = wgpu::TextureUsage::RenderAttachment;
+    device.CreateTexture(&textureDesc);
+
+    // Failure case: Texture is Render+Transient for both normal and internal usages.
+    textureDesc.usage =
+        wgpu::TextureUsage::RenderAttachment | wgpu::TextureUsage::TransientAttachment;
+    internalDesc.internalUsage =
+        wgpu::TextureUsage::RenderAttachment | wgpu::TextureUsage::TransientAttachment;
+    ASSERT_DEVICE_ERROR(device.CreateTexture(&textureDesc));
+}
+
 // Test that internal usages takes part in other validation that
 // depends on the usage.
 TEST_F(TextureInternalUsageValidationTest, UsageValidation) {

diff --git a/src/dawn/tests/unittests/validation/InternalUsageValidationTests.cpp b/src/dawn/tests/unittests/validation/InternalUsageValidationTests.cpp
index d37de44..8a32f52 100644
--- a/src/dawn/tests/unittests/validation/InternalUsageValidationTests.cpp
+++ b/src/dawn/tests/unittests/validation/InternalUsageValidationTests.cpp
@@ -108,6 +108,29 @@
     device.CreateTexture(&textureDesc);
 }
 
+// Test that TransientAttachment cannot be passed as internal usage.
+TEST_F(TextureInternalUsageValidationTest, TransientAttachment) {
+    wgpu::TextureDescriptor textureDesc = {};
+    textureDesc.size = {1, 1};
+    textureDesc.format = wgpu::TextureFormat::RGBA8Unorm;
+
+    wgpu::DawnTextureInternalUsageDescriptor internalDesc = {};
+    textureDesc.nextInChain = &internalDesc;
+
+    // Success case: Texture is Render+Transient and Render as internal usage.
+    textureDesc.usage =
+        wgpu::TextureUsage::RenderAttachment | wgpu::TextureUsage::TransientAttachment;
+    internalDesc.internalUsage = wgpu::TextureUsage::RenderAttachment;
+    device.CreateTexture(&textureDesc);
+
+    // Failure case: Texture is Render+Transient for both normal and internal usages.
+    textureDesc.usage =
+        wgpu::TextureUsage::RenderAttachment | wgpu::TextureUsage::TransientAttachment;
+    internalDesc.internalUsage =
+        wgpu::TextureUsage::RenderAttachment | wgpu::TextureUsage::TransientAttachment;
+    ASSERT_DEVICE_ERROR(device.CreateTexture(&textureDesc));
+}
+
 // Test that internal usages takes part in other validation that
 // depends on the usage.
 TEST_F(TextureInternalUsageValidationTest, UsageValidation) {