Resolve comments

Author: hyongtao-code

Lib/_pyrepl/windows_console.py

@@ -247,6 +247,26 @@ def input_hook(self):
         if nt is not None and nt._is_inputhook_installed():
             return nt._inputhook
 
+    def _has_wrapped_to_next_row(self, y: int) -> bool | None:
+        """
+        Return whether the real console cursor wrapped to the next row.
+
+        Returns:
+            True  - cursor wrapped to the next visible row
+            False - cursor did not wrap
+            None  - cannot query the real cursor position (e.g. invalid handle)
+        """
+        info = CONSOLE_SCREEN_BUFFER_INFO()
+        if not GetConsoleScreenBufferInfo(OutHandle, info):
+            err = get_last_error()
+            if err == 6:  # ERROR_INVALID_HANDLE
+                return None
+            raise WinError(err)
+
+        win_y = int(info.dwCursorPosition.Y - info.srWindow.Top)
+        expected = y - self.__offset
+        return win_y == expected + 1
+
     def __write_changed_line(
         self, y: int, oldline: str, newline: str, px_coord: int
     ) -> None:
@@ -272,23 +292,13 @@ def __write_changed_line(
 
         self.__write(newline[x_pos:])
         if wlen(newline) == self.width:
-            info = CONSOLE_SCREEN_BUFFER_INFO()
-            if not GetConsoleScreenBufferInfo(OutHandle, info):
-                err = get_last_error()
-                if err == 6:  # ERROR_INVALID_HANDLE
-                    # Best-effort fallback: cursor stays at end-of-line.
-                    self.posxy = self.width, y
-                else:
-                    raise WinError(err)
+            did_wrap = self._has_wrapped_to_next_row(y)
+            if did_wrap is True:
+                # Terminal wrapped to next row.
+                self.posxy = 0, y + 1
             else:
-                win_y = int(info.dwCursorPosition.Y - info.srWindow.Top)
-                expected = y - self.__offset
-                if win_y == expected + 1:
-                    # Terminal wrapped to next row.
-                    self.posxy = 0, y + 1
-                else:
-                    # Terminal did not wrap; cursor stays at end-of-line.
-                    self.posxy = self.width, y
+                # Terminal did not wrap; cursor stays at end-of-line.
+                self.posxy = self.width, y
         else:
             self.posxy = wlen(newline), y
 

Lib/test/test_pyrepl/test_pyrepl.py

@@ -2112,7 +2112,8 @@ class TestWindowsConsoleEolWrap(TestCase):
     """
     When a line exactly fills the terminal width, Windows consoles differ on
     whether the cursor immediately wraps to the next row (depends on host/mode).
-    We must synchronize our logical cursor position with the real console cursor.
+    We must synchronize our logical cursor position with the real console cursor
+    when possible, and degrade gracefully when it cannot be queried.
     """
 
     def _make_console_like(self, *, width: int, offset: int, vt: bool):
@@ -2136,28 +2137,17 @@ def _make_console_like(self, *, width: int, offset: int, vt: bool):
 
         return con, wc
 
-    def _run_exact_width_case(self, *, vt: bool, did_wrap: bool):
+    def _run_exact_width_case(self, *, vt: bool, did_wrap: bool | None):
         width = 10
         y = 3
         con, wc = self._make_console_like(width=width, offset=0, vt=vt)
 
-        def fake_gcsbi(_h, info):
-            info.srWindow.Top = 0
-            if did_wrap:
-                info.dwCursorPosition.X = 0
-                info.dwCursorPosition.Y = y + 1
-            else:
-                info.dwCursorPosition.X = width
-                info.dwCursorPosition.Y = y
-            return True
-
-        with patch.object(wc, "GetConsoleScreenBufferInfo", side_effect=fake_gcsbi), \
-             patch.object(wc, "OutHandle", 1):
+        with patch.object(con, "_has_wrapped_to_next_row", return_value=did_wrap):
             old = ""
             new = "a" * width
             wc.WindowsConsole._WindowsConsole__write_changed_line(con, y, old, new, 0)
 
-        if did_wrap:
+        if did_wrap is True:
             self.assertEqual(con.posxy, (0, y + 1))
             self.assertNotIn((0, y + 1), [c.args for c in con._move_relative.mock_calls])
         else:
@@ -2173,3 +2163,70 @@ def test_exact_width_line_did_not_wrap_vt_and_legacy(self):
         for vt in (True, False):
             with self.subTest(vt=vt):
                 self._run_exact_width_case(vt=vt, did_wrap=False)
+
+    def test_exact_width_line_unknown_wrap_vt_and_legacy(self):
+        # real cursor may be unavailable.
+        for vt in (True, False):
+            with self.subTest(vt=vt):
+                self._run_exact_width_case(vt=vt, did_wrap=None)
+
+
+@skipUnless(sys.platform == "win32", "Windows console behavior only")
+class TestHasWrappedToNextRow(TestCase):
+    def _make_console_like(self, *, offset: int):
+        from _pyrepl import windows_console as wc
+
+        con = object.__new__(wc.WindowsConsole)
+        setattr(con, "_WindowsConsole__offset", offset)
+        return con, wc
+
+    def test_returns_true_when_wrapped(self):
+        con, wc = self._make_console_like(offset=0)
+        y = 3
+
+        def fake_gcsbi(_h, info):
+            info.srWindow.Top = 0
+            info.dwCursorPosition.Y = y + 1
+            return True
+
+        with patch.object(wc, "GetConsoleScreenBufferInfo", side_effect=fake_gcsbi), \
+             patch.object(wc, "OutHandle", 1):
+            self.assertIs(con._has_wrapped_to_next_row(y), True)
+
+    def test_returns_false_when_not_wrapped(self):
+        con, wc = self._make_console_like(offset=0)
+        y = 3
+
+        def fake_gcsbi(_h, info):
+            info.srWindow.Top = 0
+            info.dwCursorPosition.Y = y
+            return True
+
+        with patch.object(wc, "GetConsoleScreenBufferInfo", side_effect=fake_gcsbi), \
+             patch.object(wc, "OutHandle", 1):
+            self.assertIs(con._has_wrapped_to_next_row(y), False)
+
+    def test_returns_none_on_invalid_handle(self):
+        con, wc = self._make_console_like(offset=0)
+        y = 3
+
+        def fake_gcsbi(_h, info):
+            return False
+
+        with patch.object(wc, "GetConsoleScreenBufferInfo", side_effect=fake_gcsbi), \
+             patch.object(wc, "OutHandle", 1), \
+             patch.object(wc, "get_last_error", return_value=6):  # ERROR_INVALID_HANDLE
+            self.assertIs(con._has_wrapped_to_next_row(y), None)
+
+    def test_raises_on_unexpected_error(self):
+        con, wc = self._make_console_like(offset=0)
+        y = 3
+
+        def fake_gcsbi(_h, info):
+            return False
+
+        with patch.object(wc, "GetConsoleScreenBufferInfo", side_effect=fake_gcsbi), \
+             patch.object(wc, "OutHandle", 1), \
+             patch.object(wc, "get_last_error", return_value=5):  # ERROR_ACCESS_DENIED
+            with self.assertRaises(OSError):
+                con._has_wrapped_to_next_row(y)