fix: zipfile.ZipInfo monkey-patch NameError after init cleanup (#79)

The _safe_zi wrapper referenced _orig_zi as a module-level global, but
`del _orig_zi` at the end of the init block destroyed it before any
call to ZipInfo() could use it. This broke all libraries that use
zip-based formats (python-docx, openpyxl, etc.) with:

    NameError: name '_orig_zi' is not defined

Wrap the patch in a function so _orig becomes a proper closure cell
that survives the namespace cleanup.

Adds a regression test using python-docx's Document() constructor.

Signed-off-by: danbugs <danilochiarlone@gmail.com>

Author: danbugs

examples/python-agent-driver/hl_pydriver.c

@@ -265,13 +265,15 @@ static void py_initialize_once(void)
 	 * writer (XLSX is a ZIP container). */
 	PyRun_SimpleString(
 		"import zipfile as _zf\n"
-		"_orig_zi = _zf.ZipInfo.__init__\n"
-		"def _safe_zi(self, filename='NoName', date_time=(1980,1,1,0,0,0)):\n"
-		"    if date_time[0] < 1980:\n"
-		"        date_time = (1980,1,1,0,0,0)\n"
-		"    _orig_zi(self, filename, date_time)\n"
-		"_zf.ZipInfo.__init__ = _safe_zi\n"
-		"del _zf, _orig_zi, _safe_zi\n");
+		"def _patch_zipinfo():\n"
+		"    _orig = _zf.ZipInfo.__init__\n"
+		"    def _safe(self, filename='NoName', date_time=(1980,1,1,0,0,0)):\n"
+		"        if date_time[0] < 1980:\n"
+		"            date_time = (1980,1,1,0,0,0)\n"
+		"        _orig(self, filename, date_time)\n"
+		"    _zf.ZipInfo.__init__ = _safe\n"
+		"_patch_zipinfo()\n"
+		"del _patch_zipinfo, _zf\n");
 
 	/* Monkey-patch time.sleep to call the host via /dev/hcall.
 	 * Unikraft's cooperative scheduler on Hyperlight has no timer

host/tests/pyhl_runtime.rs

@@ -117,6 +117,21 @@ fn runtime_pandas_import() {
     assert_eq!(timing.exit_code, 0);
 }
 
+// ---------------------------------------------------------------------------
+// zipfile.ZipInfo monkey-patch (pre-1980 date clamping)
+// ---------------------------------------------------------------------------
+
+#[test]
+fn runtime_zipinfo_patch_survives_cleanup() {
+    let Some((_home, mut rt)) = setup() else {
+        return;
+    };
+    let timing = rt
+        .run_code("from docx import Document\ndoc = Document()\nprint('ok')")
+        .unwrap();
+    assert_eq!(timing.exit_code, 0);
+}
+
 // ---------------------------------------------------------------------------
 // Exit code propagation
 // ---------------------------------------------------------------------------