fix: release READ FILE expression values

tools/validate_read_file_expression_cleanup.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+"""Check that READ FILE releases its evaluated path expression."""
+from pathlib import Path
+import os
+import subprocess
+import sys
+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="read-expression-cleanup-", dir=os.environ.get("TMPDIR")) as tmp:
+        tmp_path = Path(tmp)
+        source = tmp_path / "input.txt"
+        source.write_text("hello\n", encoding="utf-8")
+        script = tmp_path / "repeated_read.claro"
+        quoted = str(source).replace('\\', '\\\\').replace('"', '\\"')
+        script.write_text((f'READ FILE "{quoted}" AS contents\n' * 2000) + 'SAY contents\n', encoding="utf-8")
+        binary = tmp_path / "claro-asan"
+        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="", file=sys.stderr)
+            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: repeated READ FILE expressions retain allocations")
+            print(run.stdout, end="")
+            print(run.stderr, end="", file=sys.stderr)
+            return 1
+        if run.stdout != "hello\n\n":
+            print(f"FAIL: unexpected READ FILE output: {run.stdout!r}")
+            return 1
+        print("PASS: repeated READ FILE expressions release temporary values")
+        return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

tools/validate_v1_17.py

@@ -50,6 +50,7 @@ def main():
     run([sys.executable, "tools/validate_runtime_error_cleanup.py"])
     run([sys.executable, "tools/validate_get_argument_expression_cleanup.py"])
     run([sys.executable, "tools/validate_get_env_expression_cleanup.py"])
+    run([sys.executable, "tools/validate_read_file_expression_cleanup.py"])
     run([sys.executable, "tools/validate_version_convention.py"])
     run([str(EXE), "examples/networking.claro"])
     print("v1.18.26 validation complete")