diff --git a/list-cmake-set-plus-append-sources.sh b/list-cmake-set-plus-append-sources.sh
index 84cce5a..13140b9 100755
--- a/list-cmake-set-plus-append-sources.sh
+++ b/list-cmake-set-plus-append-sources.sh
@@ -18,6 +18,7 @@ relative_prefix=${3:-}
 
 awk -v set_name="$set_name" -v append_name="$append_name" -v relative_prefix="$relative_prefix" '
     $0 ~ "^[[:space:]]*set\\(" set_name "([[:space:]]|$)" {
+        found_set = 1
         in_set = 1
         next
     }
@@ -26,6 +27,7 @@ awk -v set_name="$set_name" -v append_name="$append_name" -v relative_prefix="$r
         next
     }
     $0 ~ "^[[:space:]]*list\\(APPEND " append_name "([[:space:]]|$)" {
+        found_append = 1
         in_append = 1
         next
     }
@@ -46,4 +48,14 @@ awk -v set_name="$set_name" -v append_name="$append_name" -v relative_prefix="$r
         }
         print line
     }
+    END {
+        if (!found_set) {
+            print "missing CMake source set: " set_name > "/dev/stderr"
+            exit 1
+        }
+        if (!found_append) {
+            print "missing CMake append source set: " append_name > "/dev/stderr"
+            exit 1
+        }
+    }
 ' core/CMakeLists.txt
diff --git a/list-cmake-set-sources.sh b/list-cmake-set-sources.sh
index 90b9b8e..e4ba9f4 100755
--- a/list-cmake-set-sources.sh
+++ b/list-cmake-set-sources.sh
@@ -17,6 +17,7 @@ relative_prefix=${2:-}
 
 awk -v set_name="$set_name" -v relative_prefix="$relative_prefix" '
     $0 ~ "^[[:space:]]*set\\(" set_name "([[:space:]]|$)" {
+        found_set = 1
         in_list = 1
         next
     }
@@ -36,4 +37,10 @@ awk -v set_name="$set_name" -v relative_prefix="$relative_prefix" '
         }
         print line
     }
+    END {
+        if (!found_set) {
+            print "missing CMake source set: " set_name > "/dev/stderr"
+            exit 1
+        }
+    }
 ' core/CMakeLists.txt
diff --git a/test-all-native.sh b/test-all-native.sh
index ca6d449..bdcb81d 100755
--- a/test-all-native.sh
+++ b/test-all-native.sh
@@ -29,6 +29,8 @@ missing_api_source_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_missing_rs274_api_proje
 missing_core_source_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_missing_core_source.XXXXXX.log")
 missing_bridge_source_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_missing_bridge_smoke_project_source.XXXXXX.log")
 escaped_project_source_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_escaped_project_source.XXXXXX.log")
+missing_cmake_set_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_missing_cmake_set.XXXXXX.log")
+missing_cmake_append_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_missing_cmake_append.XXXXXX.log")
 missing_support_object_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_missing_linuxcnc_support_object.XXXXXX.log")
 missing_source_manifest=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_native_syntax_missing_source_manifest.XXXXXX.txt")
 missing_source_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_native_syntax_missing_source.XXXXXX.log")
@@ -59,6 +61,8 @@ cleanup_native_test_temps() {
         "$missing_core_source_log" \
         "$missing_bridge_source_log" \
         "$escaped_project_source_log" \
+        "$missing_cmake_set_log" \
+        "$missing_cmake_append_log" \
         "$missing_support_object_log" \
         "$missing_source_manifest" \
         "$missing_source_log" \
@@ -174,6 +178,8 @@ for forbidden_manual_cleanup in \
     'rm -f "$missing_core_source_log"' \
     'rm -f "$missing_bridge_source_log"' \
     'rm -f "$escaped_project_source_log"' \
+    'rm -f "$missing_cmake_set_log"' \
+    'rm -f "$missing_cmake_append_log"' \
     'rm -f "$missing_support_object_log"' \
     'rm -f "$missing_source_manifest" "$missing_source_log"' \
     'rm -f "$kinematics_unknown_filter_log"' \
@@ -214,9 +220,31 @@ fi
 grep -F 'exec 9>"${TMPDIR:-/tmp}/cnc_sim_rs274_source_link.lock"' test-linuxcnc-source-link.sh >/dev/null
 grep -F "flock 9" test-linuxcnc-source-link.sh >/dev/null
 grep -F "missing LinuxCNC support object" list-linuxcnc-source-support-objects.sh >/dev/null
+grep -F 'missing CMake source set: " set_name' list-cmake-set-sources.sh >/dev/null
+grep -F 'missing CMake append source set: " append_name' list-cmake-set-plus-append-sources.sh >/dev/null
 grep -F 'echo "$missing_path_message: $path"' list-filtered-existing-paths.sh >/dev/null
 grep -F 'project source path must stay project-relative: $path' list-filtered-existing-paths.sh >/dev/null
 grep -F "build LinuxCNC first or set LINUXCNC_ROOT to a built tree" list-linuxcnc-source-support-objects.sh >/dev/null
+if ./list-cmake-set-sources.sh does_not_exist_cmake_set >"$missing_cmake_set_log" 2>&1; then
+    echo "CMake source-set lister accepted a missing set" >&2
+    exit 1
+fi
+if ! grep -F "missing CMake source set: does_not_exist_cmake_set" "$missing_cmake_set_log" >/dev/null; then
+    echo "CMake source-set lister did not report missing sets clearly" >&2
+    sed -n '1,20p' "$missing_cmake_set_log" >&2
+    exit 1
+fi
+if ./list-cmake-set-plus-append-sources.sh \
+    cnc_sim_core_sources \
+    does_not_exist_append_set >"$missing_cmake_append_log" 2>&1; then
+    echo "combined CMake source-set lister accepted a missing append set" >&2
+    exit 1
+fi
+if ! grep -F "missing CMake append source set: does_not_exist_append_set" "$missing_cmake_append_log" >/dev/null; then
+    echo "combined CMake source-set lister did not report missing append sets clearly" >&2
+    sed -n '1,20p' "$missing_cmake_append_log" >&2
+    exit 1
+fi
 if printf '../core/src/canon_event_sink.cpp\n' | ./list-filtered-existing-paths.sh \
     --project-relative \
     "" \