bpo-1104: msilib.SummaryInfo.GetProperty() truncates the string by one character (GH-4517)

Add one char to MsiSummaryInfoGetProperty() output
Based on the patch in bpo-1104 by Anthony Tuininga (atuining) and Mark McMahon (markm).

Lib/test/test_msilib.py

@@ -1,5 +1,5 @@
 """ Test suite for the code in msilib """
-import os.path
+import os
 import unittest
 from test.support import TESTFN, import_module, unlink
 msilib = import_module('msilib')
@@ -42,6 +42,29 @@ class MsiDatabaseTestCase(unittest.TestCase):
         )
         self.addCleanup(unlink, db_path)
 
+    def test_summaryinfo_getproperty_issue1104(self):
+        db, db_path = init_database()
+        try:
+            sum_info = db.GetSummaryInformation(99)
+            title = sum_info.GetProperty(msilib.PID_TITLE)
+            self.assertEqual(title, b"Installation Database")
+
+            sum_info.SetProperty(msilib.PID_TITLE, "a" * 999)
+            title = sum_info.GetProperty(msilib.PID_TITLE)
+            self.assertEqual(title, b"a" * 999)
+
+            sum_info.SetProperty(msilib.PID_TITLE, "a" * 1000)
+            title = sum_info.GetProperty(msilib.PID_TITLE)
+            self.assertEqual(title, b"a" * 1000)
+
+            sum_info.SetProperty(msilib.PID_TITLE, "a" * 1001)
+            title = sum_info.GetProperty(msilib.PID_TITLE)
+            self.assertEqual(title, b"a" * 1001)
+        finally:
+            db = None
+            sum_info = None
+            os.unlink(db_path)
+
     def test_database_open_failed(self):
         with self.assertRaises(msilib.MSIError) as cm:
             msilib.OpenDatabase('non-existent.msi', msilib.MSIDBOPEN_READONLY)
@@ -92,7 +115,7 @@ class Test_make_id(unittest.TestCase):
     def test_invalid_any_char(self):
         self.assertEqual(
             msilib.make_id(".s\x82ort"), "_.s_ort")
-        self.assertEqual    (
+        self.assertEqual(
             msilib.make_id(".s\x82o?*+rt"), "_.s_o___rt")
 
 

Misc/NEWS.d/next/Windows/2017-11-24-12-53-54.bpo-1104.1CWSZp.rst

@@ -0,0 +1,2 @@
+Correctly handle string length in ``msilib.SummaryInfo.GetProperty()`` to
+prevent it from truncating the last character.

PC/_msi.c

@@ -555,7 +555,7 @@ summary_getproperty(msiobj* si, PyObject *args)
     FILETIME fval;
     char sbuf[1000];
     char *sval = sbuf;
-    DWORD ssize = sizeof(sval);
+    DWORD ssize = sizeof(sbuf);
 
     if (!PyArg_ParseTuple(args, "i:GetProperty", &field))
         return NULL;
@@ -563,6 +563,7 @@ summary_getproperty(msiobj* si, PyObject *args)
     status = MsiSummaryInfoGetProperty(si->h, field, &type, &ival,
         &fval, sval, &ssize);
     if (status == ERROR_MORE_DATA) {
+        ssize++;
         sval = malloc(ssize);
         if (sval == NULL) {
             return PyErr_NoMemory();
@@ -572,21 +573,29 @@ summary_getproperty(msiobj* si, PyObject *args)
     }
 
     switch(type) {
-        case VT_I2: case VT_I4:
-            return PyLong_FromLong(ival);
+        case VT_I2:
+        case VT_I4:
+            result = PyLong_FromLong(ival);
+            break;
         case VT_FILETIME:
             PyErr_SetString(PyExc_NotImplementedError, "FILETIME result");
-            return NULL;
+            result = NULL;
+            break;
         case VT_LPSTR:
             result = PyBytes_FromStringAndSize(sval, ssize);
-            if (sval != sbuf)
-                free(sval);
-            return result;
+            break;
         case VT_EMPTY:
-            Py_RETURN_NONE;
+            Py_INCREF(Py_None);
+            result = Py_None;
+            break;
+        default:
+            PyErr_Format(PyExc_NotImplementedError, "result of type %d", type);
+            result = NULL;
+            break;
     }
-    PyErr_Format(PyExc_NotImplementedError, "result of type %d", type);
-    return NULL;
+    if (sval != sbuf)
+        free(sval);
+    return result;
 }
 
 static PyObject*