diff --git a/list-linuxcnc-manifest-sources.sh b/list-linuxcnc-manifest-sources.sh
index 2771058..b45a624 100755
--- a/list-linuxcnc-manifest-sources.sh
+++ b/list-linuxcnc-manifest-sources.sh
@@ -44,13 +44,20 @@ case "$output_mode" in
 esac
 
 seen_sources=()
-while IFS=: read -r group path note; do
-    case "$group" in
+manifest_line_number=0
+while IFS= read -r manifest_line || [[ -n "$manifest_line" ]]; do
+    manifest_line_number=$((manifest_line_number + 1))
+    case "$manifest_line" in
         ""|\#*)
             continue
             ;;
     esac
 
+    IFS=: read -r group path note extra <<<"$manifest_line"
+    if [[ -z "$group" || -z "$path" || -z "$note" || -n "${extra:-}" ]]; then
+        echo "bad manifest line $manifest_line_number: $manifest_line" >&2
+        exit 1
+    fi
     if ! contains_group "$allowed_groups" "$group"; then
         echo "unknown manifest group: $group" >&2
         exit 1
diff --git a/test-all-native.sh b/test-all-native.sh
index 3d544bb..d1963d1 100755
--- a/test-all-native.sh
+++ b/test-all-native.sh
@@ -1013,6 +1013,38 @@ for script in \
     fi
 done
 
+printf 'core:src/emc/rs274ngc/interp_arc.cc\n' >"$bad_line_manifest"
+if ./list-linuxcnc-manifest-sources.sh \
+    "$bad_line_manifest" \
+    core \
+    relative \
+    core \
+    core \
+    "missing manifest source" >"$bad_line_log" 2>&1; then
+    echo "common manifest source lister accepted bad manifest line" >&2
+    exit 1
+fi
+if ! grep -F "bad manifest line 1: core:src/emc/rs274ngc/interp_arc.cc" "$bad_line_log" >/dev/null; then
+    echo "common manifest source lister did not report bad manifest line clearly" >&2
+    sed -n '1,20p' "$bad_line_log" >&2
+    exit 1
+fi
+for script in \
+    list-linuxcnc-source-manifest-sources.sh \
+    test-linuxcnc-source-syntax.sh \
+    test-linuxcnc-source-objects.sh \
+    test-linuxcnc-source-link.sh; do
+    if "./$script" "$bad_line_manifest" >"$bad_line_log" 2>&1; then
+        echo "$script accepted bad manifest line" >&2
+        exit 1
+    fi
+    if ! grep -F "bad manifest line 1: core:src/emc/rs274ngc/interp_arc.cc" "$bad_line_log" >/dev/null; then
+        echo "$script did not report bad manifest line clearly" >&2
+        sed -n '1,20p' "$bad_line_log" >&2
+        exit 1
+    fi
+done
+
 ./list-linuxcnc-source-manifest-sources.sh "$manifest" core >/dev/null
 native_manifest_core=$(./list-linuxcnc-source-manifest-sources.sh "$manifest" core)
 grep -Fx "src/emc/rs274ngc/interp_arc.cc" <<<"$native_manifest_core" >/dev/null