Add a CLI regression test for a project with empty settings

Runs --info over a copy of a shipped model whose Metadata/project_settings.config
has been rewritten to an empty object, so the test keeps covering the crash no
matter what settings the shipped models carry later.

Verified both ways: the test passes against this branch and fails with a
segmentation fault against a build without the guards.

tests/cli/CMakeLists.txt

@@ -11,6 +11,13 @@ endif ()
 
 add_test(NAME cli_strict_mode
     COMMAND bash ${CMAKE_CURRENT_SOURCE_DIR}/test_cli_strict.sh $<TARGET_FILE:OrcaSlicer> ${ORCA_CLI_TEST_PYTHON})
+add_test(NAME cli_empty_project_config
+    COMMAND bash ${CMAKE_CURRENT_SOURCE_DIR}/test_cli_empty_project_config.sh $<TARGET_FILE:OrcaSlicer> ${ORCA_CLI_TEST_PYTHON} ${CMAKE_SOURCE_DIR})
+set_tests_properties(cli_empty_project_config PROPERTIES
+    LABELS "CLI;RequiresApp"
+    SKIP_RETURN_CODE 77
+    TIMEOUT 300)
+
 set_tests_properties(cli_strict_mode PROPERTIES
     LABELS "CLI;RequiresApp"
     SKIP_RETURN_CODE 77

tests/cli/test_cli_empty_project_config.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+# Regression check: a 3mf whose Metadata/project_settings.config carries no settings must load.
+#
+# The CLI reads printable_height out of the project config with opt_float(), which dereferences
+# what option<>() returns. With create = false that is null when the key is absent, so a project
+# saved without settings used to take the CLI down with a segfault. Both models in
+# resources/handy_models are such files.
+#
+# usage: test_cli_empty_project_config.sh <orca-slicer binary> <python3> <source dir>
+set -u
+
+BIN="${1:-}"
+PY="${2:-python3}"
+SRC="${3:-}"
+# 77 is the test's SKIP_RETURN_CODE.
+[ -x "$BIN" ] || { echo "SKIP: orca-slicer binary not found: $BIN"; exit 77; }
+[ -f "$SRC/resources/handy_models/OrcaBadge.3mf" ] || { echo "SKIP: handy model not found"; exit 77; }
+
+WORK="$(mktemp -d "${TMPDIR:-/tmp}/orca-cli-emptycfg.XXXXXX")"
+trap 'rm -rf "$WORK"' EXIT
+mkdir -p "$WORK/datadir"
+
+# Rewrite the project settings to an empty object, so the test holds no matter what the shipped
+# models carry later on.
+cp "$SRC/resources/handy_models/OrcaBadge.3mf" "$WORK/empty_config.3mf"
+"$PY" - "$WORK/empty_config.3mf" <<'PYEOF'
+import shutil, sys, zipfile
+
+path = sys.argv[1]
+entry = "Metadata/project_settings.config"
+with zipfile.ZipFile(path) as src:
+    items = [(i, src.read(i.filename)) for i in src.infolist()]
+with zipfile.ZipFile(path + ".new", "w", zipfile.ZIP_DEFLATED) as dst:
+    seen = False
+    for info, data in items:
+        if info.filename == entry:
+            data, seen = b"{\n}\n", True
+        dst.writestr(info, data)
+    if not seen:
+        dst.writestr(entry, b"{\n}\n")
+shutil.move(path + ".new", path)
+PYEOF
+
+"$BIN" --datadir "$WORK/datadir" --info "$WORK/empty_config.3mf" > "$WORK/info.txt" 2>&1
+rc=$?
+if [ $rc -ne 0 ]; then
+    echo "FAIL: --info on a project with empty settings exited $rc"
+    tail -20 "$WORK/info.txt"
+    exit 1
+fi
+grep -q "size_x" "$WORK/info.txt" || { echo "FAIL: --info printed no geometry"; cat "$WORK/info.txt"; exit 1; }
+echo "PASS: a project with empty settings loads"