[3.13] pythongh-82378 fix sys.tracebacklimit in pyrepl, approach 2 (pythonGH-123062)

Make sure that pyrepl uses the same logic for sys.tracebacklimit as both
the basic repl and the standard sys.excepthook
(cherry picked from commit 63603bc)

Co-authored-by: CF Bolz-Tereick <[email protected]>

Author: cfbolz

Lib/_pyrepl/console.py

@@ -162,10 +162,15 @@ def __init__(
         self.can_colorize = _colorize.can_colorize()
 
     def showsyntaxerror(self, filename=None, **kwargs):
-        super().showsyntaxerror(colorize=self.can_colorize, **kwargs)
-
-    def showtraceback(self):
-        super().showtraceback(colorize=self.can_colorize)
+        super().showsyntaxerror(**kwargs)
+
+    def _excepthook(self, typ, value, tb):
+        import traceback
+        lines = traceback.format_exception(
+                typ, value, tb,
+                colorize=self.can_colorize,
+                limit=traceback.BUILTIN_EXCEPTION_LIMIT)
+        self.write(''.join(lines))
 
     def runsource(self, source, filename="<input>", symbol="single"):
         try:

Lib/code.py

@@ -106,72 +106,71 @@ def showsyntaxerror(self, filename=None, **kwargs):
         The output is written by self.write(), below.
 
         """
-        colorize = kwargs.pop('colorize', False)
-        type, value, tb = sys.exc_info()
-        sys.last_exc = value
-        sys.last_type = type
-        sys.last_value = value
-        sys.last_traceback = tb
-        if filename and type is SyntaxError:
-            # Work hard to stuff the correct filename in the exception
-            try:
-                msg, (dummy_filename, lineno, offset, line) = value.args
-            except ValueError:
-                # Not the format we expect; leave it alone
-                pass
-            else:
-                # Stuff in the right filename
-                value = SyntaxError(msg, (filename, lineno, offset, line))
-                sys.last_exc = sys.last_value = value
-        # Set the line of text that the exception refers to
-        source = kwargs.pop('source', '')
-        lines = source.splitlines()
-        if (source and type is SyntaxError
-                and not value.text and len(lines) >= value.lineno):
-            value.text = lines[value.lineno - 1]
-        if sys.excepthook is sys.__excepthook__:
-            lines = traceback.format_exception_only(type, value, colorize=colorize)
-            self.write(''.join(lines))
-        else:
-            # If someone has set sys.excepthook, we let that take precedence
-            # over self.write
-            self._call_excepthook(type, value, tb)
+        try:
+            typ, value, tb = sys.exc_info()
+            if filename and typ is SyntaxError:
+                # Work hard to stuff the correct filename in the exception
+                try:
+                    msg, (dummy_filename, lineno, offset, line) = value.args
+                except ValueError:
+                    # Not the format we expect; leave it alone
+                    pass
+                else:
+                    # Stuff in the right filename
+                    value = SyntaxError(msg, (filename, lineno, offset, line))
+            source = kwargs.pop('source', "")
+            self._showtraceback(typ, value, None, source)
+        finally:
+            typ = value = tb = None
 
-    def showtraceback(self, **kwargs):
+    def showtraceback(self):
         """Display the exception that just occurred.
 
         We remove the first stack item because it is our own code.
 
         The output is written by self.write(), below.
 
         """
-        colorize = kwargs.pop('colorize', False)
-        sys.last_type, sys.last_value, last_tb = ei = sys.exc_info()
-        sys.last_traceback = last_tb
-        sys.last_exc = ei[1]
         try:
-            if sys.excepthook is sys.__excepthook__:
-                lines = traceback.format_exception(ei[0], ei[1], last_tb.tb_next, colorize=colorize)
-                self.write(''.join(lines))
-            else:
-                # If someone has set sys.excepthook, we let that take precedence
-                # over self.write
-                self._call_excepthook(ei[0], ei[1], last_tb)
+            typ, value, tb = sys.exc_info()
+            self._showtraceback(typ, value, tb.tb_next, "")
         finally:
-            last_tb = ei = None
+            typ = value = tb = None
 
-    def _call_excepthook(self, typ, value, tb):
-        try:
-            sys.excepthook(typ, value, tb)
-        except SystemExit:
-            raise
-        except BaseException as e:
-            e.__context__ = None
-            print('Error in sys.excepthook:', file=sys.stderr)
-            sys.__excepthook__(type(e), e, e.__traceback__.tb_next)
-            print(file=sys.stderr)
-            print('Original exception was:', file=sys.stderr)
-            sys.__excepthook__(typ, value, tb)
+
+    def _showtraceback(self, typ, value, tb, source):
+        sys.last_type = typ
+        sys.last_traceback = tb
+        value = value.with_traceback(tb)
+        # Set the line of text that the exception refers to
+        lines = source.splitlines()
+        if (source and typ is SyntaxError
+                and not value.text and len(lines) >= value.lineno):
+            value.text = lines[value.lineno - 1]
+        sys.last_exc = sys.last_value = value
+        if sys.excepthook is sys.__excepthook__:
+            self._excepthook(typ, value, tb)
+        else:
+            # If someone has set sys.excepthook, we let that take precedence
+            # over self.write
+            try:
+                sys.excepthook(typ, value, tb)
+            except SystemExit:
+                raise
+            except BaseException as e:
+                e.__context__ = None
+                e = e.with_traceback(e.__traceback__.tb_next)
+                print('Error in sys.excepthook:', file=sys.stderr)
+                sys.__excepthook__(type(e), e, e.__traceback__)
+                print(file=sys.stderr)
+                print('Original exception was:', file=sys.stderr)
+                sys.__excepthook__(typ, value, tb)
+
+    def _excepthook(self, typ, value, tb):
+        # This method is being overwritten in
+        # _pyrepl.console.InteractiveColoredConsole
+        lines = traceback.format_exception(typ, value, tb)
+        self.write(''.join(lines))
 
     def write(self, data):
         """Write a string.

Lib/test/test_pyrepl/test_pyrepl.py

@@ -1020,7 +1020,7 @@ def test_dumb_terminal_exits_cleanly(self):
         env.update({"TERM": "dumb"})
         output, exit_code = self.run_repl("exit()\n", env=env)
         self.assertEqual(exit_code, 0)
-        self.assertIn("warning: can\'t use pyrepl", output)
+        self.assertIn("warning: can't use pyrepl", output)
         self.assertNotIn("Exception", output)
         self.assertNotIn("Traceback", output)
 
@@ -1100,6 +1100,38 @@ def test_not_wiping_history_file(self):
         self.assertIn("spam", output)
         self.assertNotEqual(pathlib.Path(hfile.name).stat().st_size, 0)
 
+    @force_not_colorized
+    def test_proper_tracebacklimit(self):
+        env = os.environ.copy()
+        for set_tracebacklimit in [True, False]:
+            commands = ("import sys\n" +
+                        ("sys.tracebacklimit = 1\n" if set_tracebacklimit else "") +
+                        "def x1(): 1/0\n\n"
+                        "def x2(): x1()\n\n"
+                        "def x3(): x2()\n\n"
+                        "x3()\n"
+                        "exit()\n")
+
+            for basic_repl in [True, False]:
+                if basic_repl:
+                    env["PYTHON_BASIC_REPL"] = "1"
+                else:
+                    env.pop("PYTHON_BASIC_REPL", None)
+                with self.subTest(set_tracebacklimit=set_tracebacklimit,
+                                  basic_repl=basic_repl):
+                    output, exit_code = self.run_repl(commands, env=env)
+                    if "can't use pyrepl" in output:
+                        self.skipTest("pyrepl not available")
+                    self.assertIn("in x1", output)
+                    if set_tracebacklimit:
+                        self.assertNotIn("in x2", output)
+                        self.assertNotIn("in x3", output)
+                        self.assertNotIn("in <module>", output)
+                    else:
+                        self.assertIn("in x2", output)
+                        self.assertIn("in x3", output)
+                        self.assertIn("in <module>", output)
+
     def run_repl(
         self,
         repl_input: str | list[str],

Misc/NEWS.d/next/Library/2024-07-31-14-55-41.gh-issue-82378.eZvYmR.rst

@@ -0,0 +1,2 @@
+Make sure that the new :term:`REPL` interprets :data:`sys.tracebacklimit` in
+the same way that the classic REPL did.