From f9bc615d9a6eb8fa2db9332ec22eea42c0404134 Mon Sep 17 00:00:00 2001
From: Ben Boeckel <ben.boeckel@kitware.com>
Date: Sun, 15 Jun 2025 21:24:49 +0200
Subject: [PATCH] pchreuse: ban PCH reuse from targets which disable PCH

---
 Source/cmGeneratorTarget.cxx                  | 18 ++++++
 .../PchReuseWithoutPch-result.txt             |  1 +
 .../PchReuseWithoutPch-stderr.txt             |  4 ++
 .../PchReuseWithoutPch.cmake                  | 60 +++++++++++++++++++
 .../PrecompileHeaders/RunCMakeTest.cmake      |  1 +
 5 files changed, 84 insertions(+)
 create mode 100644 Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch-result.txt
 create mode 100644 Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch-stderr.txt
 create mode 100644 Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch.cmake

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 7ec51bb086..a86e469557 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -2860,6 +2860,15 @@ cmGeneratorTarget const* cmGeneratorTarget::GetPchReuseTarget() const
   }
 
   if (generatorTarget) {
+    if (generatorTarget->GetPropertyAsBool("DISABLE_PRECOMPILE_HEADERS")) {
+      this->Makefile->IssueMessage(
+        MessageType::FATAL_ERROR,
+        cmStrCat(
+          "Target \"", *pchReuseFrom, "\" for the \"", this->GetName(),
+          R"(" target's "PRECOMPILE_HEADERS_REUSE_FROM" property has set "DISABLE_PRECOMPILE_HEADERS".)"));
+      return nullptr;
+    }
+
     if (auto const* recurseReuseTarget =
           generatorTarget->GetPchReuseTarget()) {
       return recurseReuseTarget;
@@ -2904,6 +2913,15 @@ cmGeneratorTarget* cmGeneratorTarget::GetPchReuseTarget()
   }
 
   if (generatorTarget) {
+    if (generatorTarget->GetPropertyAsBool("DISABLE_PRECOMPILE_HEADERS")) {
+      this->Makefile->IssueMessage(
+        MessageType::FATAL_ERROR,
+        cmStrCat(
+          "Target \"", *pchReuseFrom, "\" for the \"", this->GetName(),
+          R"(" target's "PRECOMPILE_HEADERS_REUSE_FROM" property has set "DISABLE_PRECOMPILE_HEADERS".)"));
+      return nullptr;
+    }
+
     if (auto* recurseReuseTarget = generatorTarget->GetPchReuseTarget()) {
       return recurseReuseTarget;
     }
diff --git a/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch-result.txt b/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch-result.txt
new file mode 100644
index 0000000000..d00491fd7e
--- /dev/null
+++ b/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch-stderr.txt b/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch-stderr.txt
new file mode 100644
index 0000000000..a2d912b4a1
--- /dev/null
+++ b/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch-stderr.txt
@@ -0,0 +1,4 @@
+CMake Error in CMakeLists.txt:
+  Target "pch-generator" for the "reuse_from_nopch" target's
+  "PRECOMPILE_HEADERS_REUSE_FROM" property has set
+  "DISABLE_PRECOMPILE_HEADERS".
diff --git a/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch.cmake b/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch.cmake
new file mode 100644
index 0000000000..316793e0fc
--- /dev/null
+++ b/Tests/RunCMake/PrecompileHeaders/PchReuseWithoutPch.cmake
@@ -0,0 +1,60 @@
+enable_language(CXX)
+
+if(CMAKE_CXX_COMPILE_OPTIONS_USE_PCH)
+  add_definitions(-DHAVE_PCH_SUPPORT)
+endif()
+
+######################################################################
+
+file(WRITE ${CMAKE_BINARY_DIR}/pch.cxx [=[
+void nothing()
+{
+}
+]=])
+
+file(WRITE ${CMAKE_BINARY_DIR}/string.hxx [=[
+#include <string.h>
+
+namespace std {
+  struct string
+  {
+    char storage[20];
+
+    string(const char* s) {
+      strcpy(storage, s);
+    }
+
+    const char* c_str() const {
+      return storage;
+    }
+  };
+}
+]=])
+
+add_library(pch-generator ${CMAKE_BINARY_DIR}/pch.cxx)
+target_precompile_headers(pch-generator PRIVATE ${CMAKE_BINARY_DIR}/string.hxx)
+set_property(TARGET pch-generator PROPERTY DISABLE_PRECOMPILE_HEADERS 1)
+
+######################################################################
+
+file(WRITE ${CMAKE_BINARY_DIR}/message.cxx [=[
+#include "message.hxx"
+
+#ifndef HAVE_PCH_SUPPORT
+  #include "string.hxx"
+#endif
+
+const char* message()
+{
+  static std::string greeting("hi there");
+  return greeting.c_str();
+}
+]=])
+
+file(WRITE ${CMAKE_BINARY_DIR}/message.hxx [=[
+const char* message();
+]=])
+
+add_library(reuse_from_nopch ${CMAKE_BINARY_DIR}/message.cxx)
+target_precompile_headers(reuse_from_nopch REUSE_FROM pch-generator)
+target_include_directories(reuse_from_nopch PRIVATE ${CMAKE_BINARY_DIR})
diff --git a/Tests/RunCMake/PrecompileHeaders/RunCMakeTest.cmake b/Tests/RunCMake/PrecompileHeaders/RunCMakeTest.cmake
index 386bbe2801..f18b1d74f6 100644
--- a/Tests/RunCMake/PrecompileHeaders/RunCMakeTest.cmake
+++ b/Tests/RunCMake/PrecompileHeaders/RunCMakeTest.cmake
@@ -33,6 +33,7 @@ run_build_verbose(PchReuseFromIgnoreOwnProps)
 run_build_verbose(PchReuseFromUseUpdatedProps)
 run_build_verbose(PchReuseConsistency)
 run_cmake(PchReuseFromCycle)
+run_cmake(PchReuseWithoutPch)
 run_cmake(PchMultilanguage)
 run_build_verbose(PchReuseDeclarationOrder)
 if(RunCMake_GENERATOR MATCHES "Make|Ninja")