From bb23f659280fb5de7ed0b63d7f3e8b5c1d58c7e7 Mon Sep 17 00:00:00 2001
From: Martin Duffy <martin.duffy@kitware.com>
Date: Wed, 14 Jan 2026 11:47:38 -0500
Subject: instrumentation: Fix crash on cmake_instrumentation() call in initial
 cache

---
 Source/cmake.cxx                                      | 19 ++++++++++++++-----
 Source/cmake.h                                        |  1 +
 Tests/RunCMake/Instrumentation/RunCMakeTest.cmake     |  5 +++++
 .../cmake-command-initial-cache-stderr.txt            |  4 ++++
 Tests/RunCMake/Instrumentation/initial.cmake.in       |  5 +++++
 .../query/cmake-command-initial-cache.cmake           |  0
 6 files changed, 29 insertions(+), 5 deletions(-)
 create mode 100644 Tests/RunCMake/Instrumentation/cmake-command-initial-cache-stderr.txt
 create mode 100644 Tests/RunCMake/Instrumentation/initial.cmake.in
 create mode 100644 Tests/RunCMake/Instrumentation/query/cmake-command-initial-cache.cmake

diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index 1b361cb..a181aee 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -713,6 +713,7 @@ bool cmake::SetCacheArgs(std::vector<std::string> const& args)
         // relative to $PWD.
         auto path = cmSystemTools::ToNormalizedPathOnDisk(value);
         state->InitializeFileAPI();
+        state->InitializeInstrumentation();
         state->ReadListFile(args, path);
         return true;
       } },
@@ -2619,11 +2620,7 @@ int cmake::ActualConfigure()
 #if !defined(CMAKE_BOOTSTRAP)
   this->InitializeFileAPI();
   this->FileAPI->ReadQueries();
-
-  this->Instrumentation = cm::make_unique<cmInstrumentation>(
-    this->State->GetBinaryDirectory(),
-    cmInstrumentation::LoadQueriesAfter::No);
-  this->Instrumentation->ClearGeneratedQueries();
+  this->InitializeInstrumentation();
 
   if (!this->GetIsInTryCompile()) {
     this->TruncateOutputLog("CMakeConfigureLog.yaml");
@@ -2886,6 +2883,18 @@ void cmake::InitializeFileAPI()
 #endif
 }
 
+void cmake::InitializeInstrumentation()
+{
+#ifndef CMAKE_BOOTSTRAP
+  if (!this->Instrumentation) {
+    this->Instrumentation = cm::make_unique<cmInstrumentation>(
+      this->State->GetBinaryDirectory(),
+      cmInstrumentation::LoadQueriesAfter::No);
+    this->Instrumentation->ClearGeneratedQueries();
+  }
+#endif
+}
+
 // handle a command line invocation
 int cmake::Run(std::vector<std::string> const& args, bool noconfigure)
 {
diff --git a/Source/cmake.h b/Source/cmake.h
index 55494a7..39cbf01 100644
--- a/Source/cmake.h
+++ b/Source/cmake.h
@@ -671,6 +671,7 @@ public:
   }
 #endif
   void InitializeFileAPI();
+  void InitializeInstrumentation();
 
   cmState* GetState() const { return this->State.get(); }
   void SetCurrentSnapshot(cmStateSnapshot const& snapshot)
diff --git a/Tests/RunCMake/Instrumentation/RunCMakeTest.cmake b/Tests/RunCMake/Instrumentation/RunCMakeTest.cmake
index 39f06a7..ae0f25e 100644
--- a/Tests/RunCMake/Instrumentation/RunCMakeTest.cmake
+++ b/Tests/RunCMake/Instrumentation/RunCMakeTest.cmake
@@ -12,6 +12,7 @@ function(instrument test)
   set(uuid "a37d1069-1972-4901-b9c9-f194aaf2b6e0")
   set(v1 ${RunCMake_TEST_BINARY_DIR}/.cmake/instrumentation-${uuid}/v1)
   set(query_dir ${CMAKE_CURRENT_LIST_DIR}/query)
+  configure_file(${RunCMake_SOURCE_DIR}/initial.cmake.in ${RunCMake_BINARY_DIR}/initial.cmake)
 
   # Clear previous instrumentation data
   # We can't use RunCMake_TEST_NO_CLEAN 0 because we preserve queries placed in the build tree after
@@ -122,6 +123,10 @@ instrument(cmake-command-bad-arg NO_WARN)
 instrument(cmake-command-parallel-install
   BUILD INSTALL TEST NO_WARN INSTALL_PARALLEL DYNAMIC_QUERY
   CHECK_SCRIPT check-data-dir.cmake)
+instrument(cmake-command-initial-cache
+  CONFIGURE_ARG "-C ${RunCMake_BINARY_DIR}/initial.cmake"
+  CHECK_SCRIPT check-data-dir.cmake
+)
 instrument(cmake-command-resets-generated NO_WARN
   COPY_QUERIES_GENERATED
   CHECK_SCRIPT check-data-dir.cmake
diff --git a/Tests/RunCMake/Instrumentation/cmake-command-initial-cache-stderr.txt b/Tests/RunCMake/Instrumentation/cmake-command-initial-cache-stderr.txt
new file mode 100644
index 0000000..a1935a0
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/cmake-command-initial-cache-stderr.txt
@@ -0,0 +1,4 @@
+CMake Warning \(dev\) at .*
+  CMake's support for collecting instrumentation data is experimental.  It is
+  meant only for experimentation and feedback to CMake developers.
+This warning is for project developers.  Use -Wno-dev to suppress it.
diff --git a/Tests/RunCMake/Instrumentation/initial.cmake.in b/Tests/RunCMake/Instrumentation/initial.cmake.in
new file mode 100644
index 0000000..0d6285d
--- /dev/null
+++ b/Tests/RunCMake/Instrumentation/initial.cmake.in
@@ -0,0 +1,5 @@
+set(CMAKE_EXPERIMENTAL_INSTRUMENTATION @uuid@)
+cmake_instrumentation(
+  API_VERSION 1
+  DATA_VERSION 1
+)
diff --git a/Tests/RunCMake/Instrumentation/query/cmake-command-initial-cache.cmake b/Tests/RunCMake/Instrumentation/query/cmake-command-initial-cache.cmake
new file mode 100644
index 0000000..e69de29
-- 
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