bpo-37022: Fix bug where pdb's do_p/do_pp commands swallow exceptions from repr (GH-18180)

1 files changed, 19 insertions, 14 deletions

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 @@ class Pdb(bdb.Bdb, cmd.Cmd):
                 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 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         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 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         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 @@ class Pdb(bdb.Bdb, cmd.Cmd):
             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