fixup! Merge pull request #123 from johnslavik/pablo-pyrepl-docstrings

Author: pablogsal

Lib/_pyrepl/commands.py

@@ -464,8 +464,8 @@ def do(self) -> None:
 
         with self.reader.suspend():
             self.reader.msg = _sitebuiltins._Helper()()  # type: ignore[assignment]
-        self.reader.invalidate_prompt()
-
+        self.reader.invalidate_prompt()
+
 
 class invalid_key(Command):
     def do(self) -> None:
@@ -491,13 +491,11 @@ def do(self) -> None:
         pager(history, gethistoryfile())
         self.reader.console.prepare()
 
-        # We need to copy over the state so that it's consistent between
-        # console and reader, and console does not overwrite/append stuff
-        trace("command.show_history sync_rendered_screen")
-        self.reader.console.sync_rendered_screen(
-            self.reader.rendered_screen,
-            self.reader.cxy,
-        )
+        # After the pager exits, the screen state is unknown (Unix may
+        # restore via alternate screen, Windows shows pager output).
+        # Clear and force a full redraw for consistency.
+        self.reader.console.clear()
+        self.reader.invalidate_full()
 
 
 class paste_mode(Command):

Lib/_pyrepl/reader.py

@@ -357,15 +357,21 @@ def get_cached_location(
                 return 0, 0
             if buffer_from_pos is None:
                 buffer_from_pos = min(reader.pos, self.pos)
-            offset = 0
             num_common_lines = len(self.line_end_offsets)
             while num_common_lines > 0:
-                offset = self.line_end_offsets[num_common_lines - 1]
-                if buffer_from_pos > offset:
+                candidate = self.line_end_offsets[num_common_lines - 1]
+                if buffer_from_pos > candidate:
                     break
                 num_common_lines -= 1
-            else:
-                offset = 0
+            # Prompt-only leading rows consume no buffer content. Reusing them
+            # in isolation causes the next incremental rebuild to emit them a
+            # second time.
+            while (
+                num_common_lines > 0
+                and self.layout_rows[num_common_lines - 1].buffer_advance == 0
+            ):
+                num_common_lines -= 1
+            offset = self.line_end_offsets[num_common_lines - 1] if num_common_lines else 0
             return offset, num_common_lines
 
     last_refresh_cache: RefreshCache = field(default_factory=RefreshCache)

Lib/_pyrepl/windows_console.py

@@ -686,7 +686,7 @@ def getpending(self) -> Event:
                     # ignore SHIFT_PRESSED and special keys
                     continue
                 if ch == "\r":
-                    ch += "\n"
+                    ch = "\n"
                 e.data += ch
         return e
 

Lib/test/test_pyrepl/test_reader.py

@@ -20,8 +20,48 @@
 colors = {overrides.get(k, k[0].lower()): v for k, v in default_theme.syntax.items()}
 
 
+def prepare_reader_multiline_prompt(*args, **kwargs):
+    reader = prepare_reader(*args, **kwargs)
+    del reader.get_prompt
+    reader.ps1 = "Python 3.15\n>>> "
+    reader.ps2 = "Python 3.15\n>>> "
+    reader.ps3 = "Python 3.15\n... "
+    reader.ps4 = "Python 3.15\n... "
+    reader.can_colorize = False
+    reader.paste_mode = False
+    return reader
+
+
 @force_not_colorized_test_class
 class TestReader(ScreenEqualMixin, TestCase):
+    def assert_multiline_prompt_screen(self, code, expected_screen, expected_cxy):
+        reader, _ = handle_all_events(
+            code_to_events(code),
+            prepare_reader=prepare_reader_multiline_prompt,
+        )
+
+        self.assertEqual(reader.screen, expected_screen)
+        self.assertEqual(reader.cxy, expected_cxy)
+
+    def test_multiline_prompt_does_not_duplicate_leading_lines(self):
+        self.assert_multiline_prompt_screen(
+            "abc",
+            ["Python 3.15", ">>> abc"],
+            (7, 1),
+        )
+
+    def test_multiline_prompt_does_not_duplicate_leading_lines_across_buffer_lines(self):
+        self.assert_multiline_prompt_screen(
+            "if x:\n    y",
+            [
+                "Python 3.15",
+                ">>> if x:",
+                "Python 3.15",
+                "...         y",
+            ],
+            (13, 3),
+        )
+
     def test_calc_screen_wrap_simple(self):
         events = code_to_events(10 * "a")
         reader, _ = handle_events_narrow_console(events)