gh-121804: always show error location for SyntaxError's in new repl

>>> def good(x, y): ... ... def bad(x, x): ... File "<python-input-13>", line 2 def bad(x, x): ... ^ SyntaxError: duplicate argument 'x' in function definition
pablogsal · Aug 19, 2024 · Jul 16, 2024 · Jul 17, 2024 · Aug 18, 2024 · Aug 18, 2024
commit f5f0d537e3215c278fcf732aefb3c45ebd219698
@@ -161,8 +161,8 @@ def __init__(
         super().__init__(locals=locals, filename=filename, local_exit=local_exit)  # type: ignore[call-arg]
         self.can_colorize = _colorize.can_colorize()
 
-    def showsyntaxerror(self, filename=None):
-        super().showsyntaxerror(colorize=self.can_colorize)
+    def showsyntaxerror(self, filename=None, **kwargs):
+        super().showsyntaxerror(colorize=self.can_colorize, **kwargs)
 
     def showtraceback(self):
         super().showtraceback(colorize=self.can_colorize)
@@ -171,7 +171,7 @@ def runsource(self, source, filename="<input>", symbol="single"):
         try:
             tree = ast.parse(source)
         except (SyntaxError, OverflowError, ValueError):
-            self.showsyntaxerror(filename)
+            self.showsyntaxerror(filename, source=source)
             return False
         if tree.body:
             *_, last_stmt = tree.body
@@ -188,10 +188,10 @@ def runsource(self, source, filename="<input>", symbol="single"):
                         f"Try the asyncio REPL ({python} -m asyncio) to use"
                         f" top-level 'await' and run background asyncio tasks."
                     )
-                self.showsyntaxerror(filename)
+                self.showsyntaxerror(filename, source=source)
                 return False
             except (OverflowError, ValueError):
-                self.showsyntaxerror(filename)
+                self.showsyntaxerror(filename, source=source)
                 return False
 
             if code is None:

diff --git a/Lib/code.py b/Lib/code.py
@@ -64,7 +64,7 @@ def runsource(self, source, filename="<input>", symbol="single"):
             code = self.compile(source, filename, symbol)
         except (OverflowError, SyntaxError, ValueError):
             # Case 1
-            self.showsyntaxerror(filename)
+            self.showsyntaxerror(filename, source=source)
             return False
 
         if code is None:
@@ -123,6 +123,10 @@ def showsyntaxerror(self, filename=None, **kwargs):
                 # Stuff in the right filename
                 value = SyntaxError(msg, (filename, lineno, offset, line))
                 sys.last_exc = sys.last_value = value
+        source = kwargs.pop('source', "")
+        if source and not value.text and type is SyntaxError:
+            # Set the line of text that the exception refers to
+            value.text = source.splitlines()[value.lineno - 1]
         if sys.excepthook is sys.__excepthook__:
             lines = traceback.format_exception_only(type, value, colorize=colorize)
             self.write(''.join(lines))

@@ -706,7 +706,7 @@ def prepend_syspath(self, filename):
             del _filename, _sys, _dirname, _dir
             \n""".format(filename))
 
-    def showsyntaxerror(self, filename=None):
+    def showsyntaxerror(self, filename=None, **kwargs):
         """Override Interactive Interpreter method: Use Colorizing
 
         Color the offending position instead of printing it and pointing at it

@@ -88,6 +88,20 @@ def test_runsource_returns_false_for_failed_compilation(self):
         self.assertFalse(result)
         self.assertIn('SyntaxError', f.getvalue())
 
+    @force_not_colorized
+    def test_runsource_show_syntax_error_location(self):
+        console = InteractiveColoredConsole()
+        source = "def f(x, x): ..."
+        f = io.StringIO()
+        with contextlib.redirect_stderr(f):
+            result = console.runsource(source)
+        self.assertFalse(result)
+        r = """
+    def f(x, x): ...
+             ^
+SyntaxError: duplicate argument 'x' in function definition"""
+        self.assertIn(r, f.getvalue())
+
     def test_runsource_shows_syntax_error_for_failed_compilation(self):
         console = InteractiveColoredConsole()
         source = "print('Hello, world!'"

diff --git a/Misc/NEWS.d/next/Library/2024-07-16-20-49-07.gh-issue-121804.gYN-In.rst b/Misc/NEWS.d/next/Library/2024-07-16-20-49-07.gh-issue-121804.gYN-In.rst
@@ -0,0 +1,3 @@
+Add new kwarg ``source`` for
+:meth:`InteractiveInterpreter.showsyntaxerror()` to support enhanced error
+messages, including error locations.  Patch by Sergey B Kirpichev.