From d6c39cd360f856c5ac3baf130bce339619c269be Mon Sep 17 00:00:00 2001
From: Steven Wu <stevenwu@apple.com>
Date: Fri, 7 Nov 2025 10:57:55 -0800
Subject: [PATCH] [CAS] Don't leak `-iapinotes-modules` clang flag in caching
 build

The search paths for apinotes are leaked when using compilation caching
but they are not needed like other search path because the apinotes are
found and stored inside include-tree.

rdar://164205657
---
 lib/ClangImporter/ClangImporter.cpp |  3 +++
 test/CAS/apinotes.swift             | 29 +++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 test/CAS/apinotes.swift

diff --git a/lib/ClangImporter/ClangImporter.cpp b/lib/ClangImporter/ClangImporter.cpp
index 6694955b31392..c3b747062d53e 100644
--- a/lib/ClangImporter/ClangImporter.cpp
+++ b/lib/ClangImporter/ClangImporter.cpp
@@ -4363,6 +4363,9 @@ ClangImporter::getSwiftExplicitModuleDirectCC1Args() const {
   FEOpts.IncludeTimestamps = false;
   FEOpts.ModuleMapFiles.clear();
 
+  // APINotesOptions.
+  instance.getAPINotesOpts().ModuleSearchPaths.clear();
+
   // IndexStorePath is forwarded from swift.
   FEOpts.IndexStorePath.clear();
 
diff --git a/test/CAS/apinotes.swift b/test/CAS/apinotes.swift
new file mode 100644
index 0000000000000..144ea3dbd2855
--- /dev/null
+++ b/test/CAS/apinotes.swift
@@ -0,0 +1,29 @@
+// REQUIRES: objc_interop
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/main.swift -o %t/deps.json -swift-version 5 -cache-compile-job -cas-path %t/cas -I %t
+
+// RUN: %FileCheck --input-file=%t/deps.json %s
+
+// CHECK-NOT: -iapinotes-modules
+
+//--- main.swift
+import A
+
+//--- module.modulemap
+module A { header "A.h" export *}
+
+//--- A.h
+#pragma once
+void a(void);
+
+//--- A.apinotes
+Name: A
+Functions:
+  - Name: a
+    Availability: none
+    AvailabilityMsg: "don't use this"