gh-90095: Make .pdbrc work properly and add some reasonable tests (#110496)

Lib/pdb.py

@@ -363,26 +363,9 @@ class Pdb(bdb.Bdb, cmd.Cmd):
                 self._chained_exceptions[self._chained_exception_index],
             )
 
-        return self.execRcLines()
-
-    # Can be executed earlier than 'setup' if desired
-    def execRcLines(self):
-        if not self.rcLines:
-            return
-        # local copy because of recursion
-        rcLines = self.rcLines
-        rcLines.reverse()
-        # execute every line only once
-        self.rcLines = []
-        while rcLines:
-            line = rcLines.pop().strip()
-            if line and line[0] != '#':
-                if self.onecmd(line):
-                    # if onecmd returns True, the command wants to exit
-                    # from the interaction, save leftover rc lines
-                    # to execute before next interaction
-                    self.rcLines += reversed(rcLines)
-                    return True
+        if self.rcLines:
+            self.cmdqueue = self.rcLines
+            self.rcLines = []
 
     # Override Bdb methods
 
@@ -571,12 +554,10 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         if isinstance(tb_or_exc, BaseException):
             assert tb is not None, "main exception must have a traceback"
         with self._hold_exceptions(_chained_exceptions):
-            if self.setup(frame, tb):
-                # no interaction desired at this time (happens if .pdbrc contains
-                # a command like "continue")
-                self.forget()
-                return
-            self.print_stack_entry(self.stack[self.curindex])
+            self.setup(frame, tb)
+            # if we have more commands to process, do not show the stack entry
+            if not self.cmdqueue:
+                self.print_stack_entry(self.stack[self.curindex])
             self._cmdloop()
             self.forget()
 
@@ -712,7 +693,7 @@ class Pdb(bdb.Bdb, cmd.Cmd):
             if marker >= 0:
                 # queue up everything after marker
                 next = line[marker+2:].lstrip()
-                self.cmdqueue.append(next)
+                self.cmdqueue.insert(0, next)
                 line = line[:marker].rstrip()
 
         # Replace all the convenience variables
@@ -737,13 +718,12 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         """Handles one command line during command list definition."""
         cmd, arg, line = self.parseline(line)
         if not cmd:
-            return
+            return False
         if cmd == 'silent':
             self.commands_silent[self.commands_bnum] = True
-            return # continue to handle other cmd def in the cmd list
+            return False  # continue to handle other cmd def in the cmd list
         elif cmd == 'end':
-            self.cmdqueue = []
-            return 1 # end of cmd list
+            return True  # end of cmd list
         cmdlist = self.commands[self.commands_bnum]
         if arg:
             cmdlist.append(cmd+' '+arg)
@@ -757,9 +737,8 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         # one of the resuming commands
         if func.__name__ in self.commands_resuming:
             self.commands_doprompt[self.commands_bnum] = False
-            self.cmdqueue = []
-            return 1
-        return
+            return True
+        return False
 
     # interface abstraction functions