fix: release GET KEY expression temporaries

tools/validate_get_key_expression_cleanup.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+"""Regression check for GET KEY expression temporaries."""
+from pathlib import Path
+import os
+import subprocess
+import tempfile
+
+ROOT = Path(__file__).resolve().parent.parent
+
+
+def main() -> int:
+    if os.name == "nt":
+        print("SKIP: LeakSanitizer check is POSIX-only")
+        return 0
+    with tempfile.TemporaryDirectory(prefix="claro-get-key-cleanup-") as tmp:
+        tmp_path = Path(tmp)
+        binary = tmp_path / "claro-lsan"
+        script = tmp_path / "get_key_expressions.claro"
+        script.write_text(
+            'SET items TO MAP\nPUT items KEY "selected" VALUE "value"\n'
+            + 'GET items KEY "selected" AS selected\n' * 2000
+            + "SAY selected\n",
+            encoding="utf-8",
+        )
+        build = subprocess.run(
+            ["gcc", "-std=c99", "-O0", "-g", "-fsanitize=address,undefined",
+             "src/claro.c", "-o", str(binary), "-lm"],
+            cwd=ROOT, text=True, capture_output=True,
+        )
+        if build.returncode:
+            print(build.stdout, end="")
+            print(build.stderr, end="")
+            return build.returncode
+        run = subprocess.run(
+            [str(binary), str(script)], cwd=ROOT, text=True, capture_output=True,
+            env={**os.environ, "ASAN_OPTIONS": "detect_leaks=1"},
+        )
+        if run.returncode or "LeakSanitizer" in run.stderr or "SUMMARY:" in run.stderr:
+            print("FAIL: GET KEY expression values still leak")
+            print(run.stdout, end="")
+            print(run.stderr, end="")
+            return 1
+        if run.stdout != "value\n":
+            print(f"FAIL: unexpected GET KEY probe output: {run.stdout!r}")
+            return 1
+        print("PASS: GET KEY expression values are released")
+        return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())