bpo-37022: Fix bug where pdb's do_p/do_pp commands swallow exceptions from repr (GH-18180) (GH-26650)
(cherry picked from commit 6544b2532df82d137b71323445a07a6e29bcdec0)
Co-authored-by: Daniel Hahler <git@thequod.de>
diff --git a/Lib/pdb.py b/Lib/pdb.py
index a888a0a..081a844 100755
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -384,8 +384,7 @@ def default(self, line):
sys.stdin = save_stdin
sys.displayhook = save_displayhook
except:
- exc_info = sys.exc_info()[:2]
- self.error(traceback.format_exception_only(*exc_info)[-1].strip())
+ self._error_exc()
def precmd(self, line):
"""Handle alias expansion and ';;' separator."""
@@ -1104,8 +1103,7 @@ def do_debug(self, arg):
try:
sys.call_tracing(p.run, (arg, globals, locals))
except Exception:
- exc_info = sys.exc_info()[:2]
- self.error(traceback.format_exception_only(*exc_info)[-1].strip())
+ self._error_exc()
self.message("LEAVING RECURSIVE DEBUGGER")
sys.settrace(self.trace_dispatch)
self.lastcmd = p.lastcmd
@@ -1163,8 +1161,7 @@ def _getval(self, arg):
try:
return eval(arg, self.curframe.f_globals, self.curframe_locals)
except:
- exc_info = sys.exc_info()[:2]
- self.error(traceback.format_exception_only(*exc_info)[-1].strip())
+ self._error_exc()
raise
def _getval_except(self, arg, frame=None):
@@ -1178,23 +1175,31 @@ def _getval_except(self, arg, frame=None):
err = traceback.format_exception_only(*exc_info)[-1].strip()
return _rstr('** raised %s **' % err)
+ def _error_exc(self):
+ exc_info = sys.exc_info()[:2]
+ self.error(traceback.format_exception_only(*exc_info)[-1].strip())
+
+ def _msg_val_func(self, arg, func):
+ try:
+ val = self._getval(arg)
+ except:
+ return # _getval() has displayed the error
+ try:
+ self.message(func(val))
+ except:
+ self._error_exc()
+
def do_p(self, arg):
"""p expression
Print the value of the expression.
"""
- try:
- self.message(repr(self._getval(arg)))
- except:
- pass
+ self._msg_val_func(arg, repr)
def do_pp(self, arg):
"""pp expression
Pretty-print the value of the expression.
"""
- try:
- self.message(pprint.pformat(self._getval(arg)))
- except:
- pass
+ self._msg_val_func(arg, pprint.pformat)
complete_print = _complete_expression
complete_p = _complete_expression
diff --git a/Lib/test/test_pdb.py b/Lib/test/test_pdb.py
index cd096e7..f944acd 100644
--- a/Lib/test/test_pdb.py
+++ b/Lib/test/test_pdb.py
@@ -391,6 +391,34 @@ def test_pdb_breakpoints_preserved_across_interactive_sessions():
(Pdb) continue
"""
+def test_pdb_pp_repr_exc():
+ """Test that do_p/do_pp do not swallow exceptions.
+
+ >>> class BadRepr:
+ ... def __repr__(self):
+ ... raise Exception('repr_exc')
+ >>> obj = BadRepr()
+
+ >>> def test_function():
+ ... import pdb; pdb.Pdb(nosigint=True, readrc=False).set_trace()
+
+ >>> with PdbTestInput([ # doctest: +NORMALIZE_WHITESPACE
+ ... 'p obj',
+ ... 'pp obj',
+ ... 'continue',
+ ... ]):
+ ... test_function()
+ --Return--
+ > <doctest test.test_pdb.test_pdb_pp_repr_exc[2]>(2)test_function()->None
+ -> import pdb; pdb.Pdb(nosigint=True, readrc=False).set_trace()
+ (Pdb) p obj
+ *** Exception: repr_exc
+ (Pdb) pp obj
+ *** Exception: repr_exc
+ (Pdb) continue
+ """
+
+
def do_nothing():
pass
diff --git a/Misc/NEWS.d/next/Library/2020-01-25-12-58-20.bpo-37022.FUZI25.rst b/Misc/NEWS.d/next/Library/2020-01-25-12-58-20.bpo-37022.FUZI25.rst
new file mode 100644
index 0000000..7b923b3
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-01-25-12-58-20.bpo-37022.FUZI25.rst
@@ -0,0 +1 @@
+:mod:`pdb` now displays exceptions from ``repr()`` with its ``p`` and ``pp`` commands.
\ No newline at end of file