#5294: Fix the behavior of pdb "continue" command when called in the top-level debugged frame.

Lib/bdb.py

@@ -109,6 +109,8 @@ class Bdb:
                self.is_skipped_module(frame.f_globals.get('__name__')):
             return False
         if frame is self.stopframe:
+            if self.stoplineno == -1:
+                return False
             return frame.f_lineno >= self.stoplineno
         while frame is not None and frame is not self.stopframe:
             if frame is self.botframe:
@@ -165,10 +167,12 @@ class Bdb:
         but only if we are to stop at or just below this level."""
         pass
 
-    def _set_stopinfo(self, stopframe, returnframe, stoplineno=-1):
+    def _set_stopinfo(self, stopframe, returnframe, stoplineno=0):
         self.stopframe = stopframe
         self.returnframe = returnframe
         self.quitting = 0
+        # stoplineno >= 0 means: stop at line >= the stoplineno
+        # stoplineno -1 means: don't stop at all
         self.stoplineno = stoplineno
 
     # Derived classes and clients can call the following methods
@@ -211,7 +215,7 @@ class Bdb:
 
     def set_continue(self):
         # Don't stop except at breakpoints or when finished
-        self._set_stopinfo(self.botframe, None)
+        self._set_stopinfo(self.botframe, None, -1)
         if not self.breaks:
             # no breakpoints; run without debugger overhead
             sys.settrace(None)

Lib/test/test_pdb.py

@@ -122,6 +122,48 @@ def test_pdb_skip_modules_with_callback():
     """
 
 
+def test_pdb_continue_in_bottomframe():
+    """Test that "continue" and "next" work properly in bottom frame (issue #5294).
+
+    >>> def test_function():
+    ...     import pdb, sys; inst = pdb.Pdb()
+    ...     inst.set_trace()
+    ...     inst.botframe = sys._getframe()  # hackery to get the right botframe
+    ...     print(1)
+    ...     print(2)
+    ...     print(3)
+    ...     print(4)
+
+    >>> with PdbTestInput([
+    ...     'next',
+    ...     'break 7',
+    ...     'continue',
+    ...     'next',
+    ...     'continue',
+    ...     'continue',
+    ... ]):
+    ...    test_function()
+    > <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>(4)test_function()
+    -> inst.botframe = sys._getframe()  # hackery to get the right botframe
+    (Pdb) next
+    > <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>(5)test_function()
+    -> print(1)
+    (Pdb) break 7
+    Breakpoint 1 at <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>:7
+    (Pdb) continue
+    1
+    2
+    > <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>(7)test_function()
+    -> print(3)
+    (Pdb) next
+    3
+    > <doctest test.test_pdb.test_pdb_continue_in_bottomframe[0]>(8)test_function()
+    -> print(4)
+    (Pdb) continue
+    4
+    """
+
+
 def pdb_invoke(method, arg):
     """Run pdb.method(arg)."""
     import pdb; getattr(pdb, method)(arg)

Misc/NEWS

@@ -475,6 +475,9 @@ C-API
 Library
 -------
 
+- Issue #5294: Fix the behavior of pdb's "continue" command when called
+  in the top-level debugged frame.
+
 - Issue #5727: Restore the ability to use readline when calling into pdb
   in doctests.