python · akulakov · Sep 17, 2021 · Sep 17, 2021 · Sep 17, 2021
@@ -543,7 +543,9 @@ can be overridden by the local file.
 
 .. pdbcommand:: retval
 
-   Print the return value for the last return of a function.
+   Print the return value for the last return of a function.  This command must
+   be used immediately after the return line is executed; *return* command can
+   be used to jump to the location where *retval* can be used.
 
 .. rubric:: Footnotes
 

@@ -1230,7 +1230,12 @@ def do_args(self, arg):
         for i in range(n):
             name = co.co_varnames[i]
             if name in dict:
-                self.message('%s = %r' % (name, dict[name]))
+                try:
+                    r = dict[name]
+                    repr(r)
+                except Exception as e:
+                    r = e
+                self.message('%s = %r' % (name, r))
             else:
                 self.message('%s = *** undefined ***' % (name,))
     do_a = do_args
@@ -1240,7 +1245,10 @@ def do_retval(self, arg):
         Print the return value for the last return of a function.
         """
         if '__return__' in self.curframe_locals:
-            self.message(repr(self.curframe_locals['__return__']))
+            try:
+                self.message(repr(self.curframe_locals['__return__']))
+            except:
+                self._error_exc()
         else:
             self.error('Not yet returned!')
     do_rv = do_retval

@@ -429,6 +429,42 @@ def test_pdb_pp_repr_exc():
     (Pdb) continue
     """
 
+def test_pdb_bad_repr():
+    # Note that return of test_function() needs to be assigned to a value;
+    # otherwise doctest tries to run repr() on it and fails.
+    """Test that args/retval commands handle bad repr objects.
+
+    >>> class BadRepr:
+    ...     def __repr__(self):
+    ...         raise AttributeError("'BadRepr' object has no attribute 'foo'")
+    ...     def __str__(self):
+    ...         return '<BadRepr>'
+    >>> obj = BadRepr()
+
+    >>> def test_function(x):
+    ...     import pdb; pdb.Pdb(nosigint=True, readrc=False).set_trace()
+    ...     return x
+
+    >>> with PdbTestInput([  # doctest: +NORMALIZE_WHITESPACE, +ELLIPSIS
+    ...     'args',
+    ...     'return',
+    ...     'retval',
+    ...     'continue',
+    ... ]):
+    ...    x = test_function(obj)
+    > <doctest test.test_pdb.test_pdb_bad_repr[2]>(3)test_function()
+    -> return x
+    (Pdb) args
+    x = AttributeError("'BadRepr' object has no attribute 'foo'")
+    (Pdb) return
+    --Return--
+    > <doctest test.test_pdb.test_pdb_bad_repr[2]>(3)test_function()...
+    -> return x
+    (Pdb) retval
+    *** AttributeError: 'BadRepr' object has no attribute 'foo'
+    (Pdb) continue
+    """
+
 
 def do_nothing():
     pass

diff --git a/Misc/NEWS.d/next/Library/2021-09-16-22-38-58.bpo-20853.J3kJay.rst b/Misc/NEWS.d/next/Library/2021-09-16-22-38-58.bpo-20853.J3kJay.rst
@@ -0,0 +1,2 @@
+In :mod:`pdb`, *args* and *retval* commands were fixed to properly handle
+objects for which :func:`repr` raises an exception.