From 4fcf3dd296d458562fcff5785b5b55868fed0691 Mon Sep 17 00:00:00 2001
From: Taylor Braun-Jones <taylor@braun-jones.org>
Date: Fri, 4 Sep 2026 13:58:51 +0000
Subject: [PATCH] CTest: Ignore a checkpoint entry for a test that is not
 pending

CheckResume() reads the checkpoint `ctest -F` resumes from and removes each
test it names.  RemoveTest() erased the iterator std::find returned without
checking it, so a checkpoint naming a test the current run does not have
pending -- one written before the test list changed, say -- erased the end
iterator of a std::list, which is undefined behavior.  Skip such an entry
instead.
---
 Source/CTest/cmCTestMultiProcessHandler.cxx | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/Source/CTest/cmCTestMultiProcessHandler.cxx b/Source/CTest/cmCTestMultiProcessHandler.cxx
index 731bda394b..ea51ccfea3 100644
--- a/Source/CTest/cmCTestMultiProcessHandler.cxx
+++ b/Source/CTest/cmCTestMultiProcessHandler.cxx
@@ -1638,8 +1638,13 @@ void cmCTestMultiProcessHandler::CheckResume()
 
 void cmCTestMultiProcessHandler::RemoveTest(int index)
 {
-  this->OrderedTests.erase(
-    std::find(this->OrderedTests.begin(), this->OrderedTests.end(), index));
+  auto const oi =
+    std::find(this->OrderedTests.begin(), this->OrderedTests.end(), index);
+  if (oi == this->OrderedTests.end()) {
+    // The checkpoint names a test this run does not have pending.
+    return;
+  }
+  this->OrderedTests.erase(oi);
   this->PendingTests.erase(index);
   this->Properties.erase(index);
   this->Completed++;