From f54a2bbd203230a92fba8fb740c73b395285d8d2 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Mon, 15 Nov 2021 19:15:38 -0600
Subject: [PATCH 01/14] Move management of current debuggers into Debugger
 class

---
 pudb/__init__.py | 12 +++++-------
 pudb/debugger.py | 10 ++++++++++
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/pudb/__init__.py b/pudb/__init__.py
index c504bfed..cca005b9 100644
--- a/pudb/__init__.py
+++ b/pudb/__init__.py
@@ -58,9 +58,6 @@ def go(self):
 builtins.__dict__["pu"] = PudbShortcuts()
 
 
-CURRENT_DEBUGGER = []
-
-
 def _tty_override():
     import os
     return os.environ.get("PUDB_TTY")
@@ -76,7 +73,8 @@ def _open_tty(tty_path):
 
 
 def _get_debugger(**kwargs):
-    if not CURRENT_DEBUGGER:
+    from pudb.debugger import Debugger
+    if not Debugger._current_debugger:
         tty_path = _tty_override()
         if tty_path and ("stdin" not in kwargs or "stdout" not in kwargs):
             tty_file, term_size = _open_tty(tty_path)
@@ -87,14 +85,14 @@ def _get_debugger(**kwargs):
         from pudb.debugger import Debugger
         dbg = Debugger(**kwargs)
 
-        CURRENT_DEBUGGER.append(dbg)
         return dbg
     else:
-        return CURRENT_DEBUGGER[0]
+        return Debugger._current_debugger[0]
 
 
 def _have_debugger():
-    return len(CURRENT_DEBUGGER) > 0
+    from pudb.debugger import Debugger
+    return bool(Debugger._current_debugger)
 
 
 import signal  # noqa
diff --git a/pudb/debugger.py b/pudb/debugger.py
index 126c43f1..ce7682cd 100644
--- a/pudb/debugger.py
+++ b/pudb/debugger.py
@@ -180,9 +180,15 @@
 # {{{ debugger interface
 
 class Debugger(bdb.Bdb):
+    _current_debugger = []
+
     def __init__(self, stdin=None, stdout=None, term_size=None, steal_output=False,
             **kwargs):
 
+        if Debugger._current_debugger:
+            raise ValueError("a Debugger instance already exists")
+        self._current_debugger.append(self)
+
         # Pass remaining kwargs to python debugger framework
         bdb.Bdb.__init__(self, **kwargs)
         self.ui = DebuggerUI(self, stdin=stdin, stdout=stdout, term_size=term_size)
@@ -200,6 +206,10 @@ def __init__(self, stdin=None, stdout=None, term_size=None, steal_output=False,
         for bpoint_descr in load_breakpoints():
             self.set_break(*bpoint_descr)
 
+    def __del__(self):
+        assert self._current_debugger == [self]
+        self._current_debugger.pop()
+
     # These (dispatch_line and set_continue) are copied from bdb with the
     # patch from https://bugs.python.org/issue16482 applied. See
     # https://github.com/inducer/pudb/pull/90.

From 4a77bd8805ff43f6f4807197565f972eaebe344b Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Mon, 15 Nov 2021 19:16:20 -0600
Subject: [PATCH 02/14] Move term_size heuristic to RemoteDebugger constructor,
 document better (gh-485)

---
 doc/starting.rst |  7 ++++---
 pudb/remote.py   | 34 +++++++++++++++++++++++++++-------
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/doc/starting.rst b/doc/starting.rst
index d17fcc6a..58e2f8dd 100644
--- a/doc/starting.rst
+++ b/doc/starting.rst
@@ -1,5 +1,5 @@
-Getting Started
----------------
+Starting the debugger
+---------------------
 
 To start debugging, simply insert::
 
@@ -81,6 +81,8 @@ connection::
     pudb:6899: Please telnet into 127.0.0.1 6899.
     pudb:6899: Waiting for client...
 
+.. automodule:: pudb.remote
+
 "Reverse" remote debugging
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
@@ -106,7 +108,6 @@ Then watch the debugger connect to netcat::
 
     pudb:9999: Now in session with 127.0.0.1:6899.
 
-
 Using the debugger after forking
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/pudb/remote.py b/pudb/remote.py
index e588fa79..876124e3 100644
--- a/pudb/remote.py
+++ b/pudb/remote.py
@@ -1,3 +1,10 @@
+"""
+.. autoclass:: RemoteDebugger
+
+.. autofunction:: set_trace
+.. autofunction:: debugger
+"""
+
 __copyright__ = """
 Copyright (C) 2009-2017 Andreas Kloeckner
 Copyright (C) 2014-2017 Aaron Meurer
@@ -77,6 +84,10 @@
 
 
 class RemoteDebugger(Debugger):
+    """
+    .. automethod:: __init__
+    """
+
     me = "pudb"
     _prev_outs = None
     _sock = None
@@ -90,8 +101,24 @@ def __init__(
         term_size=None,
         reverse=False,
     ):
+        """
+        :arg term_size: A two-tuple ``(columns, rows)``, or *None*. If *None*,
+            try to determine the terminal size automatically.
+
+            Currently, this uses a heuristic: It uses the terminal size of the
+            debuggee as that for the debugger. The idea is that you might be
+            running both in two tabs of the same terminal window, hence using
+            terminals of the same size.
+        """
         self.out = out
 
+        if term_size is None:
+            try:
+                s = struct.unpack("hh", fcntl.ioctl(1, termios.TIOCGWINSZ, "1234"))
+                term_size = (s[1], s[0])
+            except Exception:
+                term_size = (80, 24)
+
         self._prev_handles = sys.stdin, sys.stdout
         self._client, (address, port) = self.get_client(
             host=host, port=port, search_limit=port_search_limit, reverse=reverse
@@ -205,13 +232,6 @@ def set_trace(
     """Set breakpoint at current location, or a specified frame"""
     if frame is None:
         frame = _frame().f_back
-    if term_size is None:
-        try:
-            # Getting terminal size
-            s = struct.unpack("hh", fcntl.ioctl(1, termios.TIOCGWINSZ, "1234"))
-            term_size = (s[1], s[0])
-        except Exception:
-            term_size = (80, 24)
 
     return debugger(
         term_size=term_size, host=host, port=port, reverse=reverse

From 552f56a828d149a14a9b0f5124d3969daf656be4 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Mon, 15 Nov 2021 19:17:30 -0600
Subject: [PATCH 03/14] Fix post-mortem debugging for Py3

---
 pudb/__init__.py | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/pudb/__init__.py b/pudb/__init__.py
index cca005b9..47d3ab99 100644
--- a/pudb/__init__.py
+++ b/pudb/__init__.py
@@ -312,19 +312,17 @@ def post_mortem(tb=None, e_type=None, e_value=None):
 
     dbg = _get_debugger()
     dbg.reset()
-    dbg.interaction(tb.tb_frame, exc_info)
+    dbg.interaction(None, (exc_info[0], exc_info[1], tb))
 
 
 def pm():
     import sys
-    try:
-        e_type = sys.last_type
-        e_value = sys.last_value
-        tb = sys.last_traceback
-    except AttributeError:
+    exc_type, exc_val, tb = sys.exc_info()
+
+    if exc_type is None:
         # No exception on record. Do nothing.
         return
-    post_mortem(tb, e_type, e_value)
+    post_mortem()
 
 
 if __name__ == "__main__":

From 9a8e660a842b07738dfce68ffcbe3f5861e1b07d Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Wed, 17 Nov 2021 17:07:23 -0600
Subject: [PATCH 04/14] Remove unexplained stack-eating loop from post_mortem

---
 pudb/__init__.py | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/pudb/__init__.py b/pudb/__init__.py
index 47d3ab99..b3cc88fb 100644
--- a/pudb/__init__.py
+++ b/pudb/__init__.py
@@ -306,13 +306,9 @@ def post_mortem(tb=None, e_type=None, e_value=None):
     else:
         exc_info = (e_type, e_value, tb)
 
-    tb = exc_info[2]
-    while tb.tb_next is not None:
-        tb = tb.tb_next
-
     dbg = _get_debugger()
     dbg.reset()
-    dbg.interaction(None, (exc_info[0], exc_info[1], tb))
+    dbg.interaction(None, exc_info)
 
 
 def pm():

From 4b9451341b1fd1f36e4081928ca304a7efb8646d Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Thu, 16 Dec 2021 18:30:02 +0100
Subject: [PATCH 05/14] add debug_remote_on_single_rank

---
 pudb/remote.py | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/pudb/remote.py b/pudb/remote.py
index 876124e3..e296d25e 100644
--- a/pudb/remote.py
+++ b/pudb/remote.py
@@ -3,6 +3,7 @@
 
 .. autofunction:: set_trace
 .. autofunction:: debugger
+.. autofunction:: debug_remote_on_single_rank
 """
 
 __copyright__ = """
@@ -43,10 +44,11 @@
 import termios
 import struct
 import atexit
+from typing import Callable, Any
 
 from pudb.debugger import Debugger
 
-__all__ = ["PUDB_RDB_HOST", "PUDB_RDB_PORT", "default_port", "debugger", "set_trace"]
+__all__ = ["PUDB_RDB_HOST", "PUDB_RDB_PORT", "default_port", "debugger", "set_trace", "debug_remote_on_single_rank"]
 
 default_port = 6899
 
@@ -236,3 +238,22 @@ def set_trace(
     return debugger(
         term_size=term_size, host=host, port=port, reverse=reverse
     ).set_trace(frame)
+
+
+def debug_remote_on_single_rank(function: Callable, comm: Any, rank: int = 0):
+    """Run a remote debugger on a single rank of an :mod:`mpi4py` application."""
+    if comm.rank == rank:
+        dbg = debugger()
+        try:
+            dbg.runcall(function)
+        except Exception:
+            from pudb import pm
+            pm()
+
+    else:
+        try:
+            function()
+        finally:
+            from time import sleep
+            while True:
+                sleep(1)
\ No newline at end of file

From c1b68a39812408a293b12da67afa3777ebfb56f7 Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Thu, 16 Dec 2021 18:38:16 +0100
Subject: [PATCH 06/14] flake8

---
 pudb/remote.py | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/pudb/remote.py b/pudb/remote.py
index e296d25e..cbfb0353 100644
--- a/pudb/remote.py
+++ b/pudb/remote.py
@@ -48,7 +48,8 @@
 
 from pudb.debugger import Debugger
 
-__all__ = ["PUDB_RDB_HOST", "PUDB_RDB_PORT", "default_port", "debugger", "set_trace", "debug_remote_on_single_rank"]
+__all__ = ["PUDB_RDB_HOST", "PUDB_RDB_PORT", "default_port", "debugger", "set_trace",
+           "debug_remote_on_single_rank"]
 
 default_port = 6899
 
@@ -240,20 +241,20 @@ def set_trace(
     ).set_trace(frame)
 
 
-def debug_remote_on_single_rank(function: Callable, comm: Any, rank: int = 0):
+def debug_remote_on_single_rank(func: Callable, comm: Any, rank: int = 0) -> None:
     """Run a remote debugger on a single rank of an :mod:`mpi4py` application."""
     if comm.rank == rank:
         dbg = debugger()
         try:
-            dbg.runcall(function)
+            dbg.runcall(func)
         except Exception:
             from pudb import pm
             pm()
 
     else:
         try:
-            function()
+            func()
         finally:
             from time import sleep
             while True:
-                sleep(1)
\ No newline at end of file
+                sleep(1)

From cc98e275fb47b8789d561129d692d9265f8eed3e Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 29 Dec 2021 12:28:54 +0100
Subject: [PATCH 07/14] better doc

---
 pudb/remote.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/pudb/remote.py b/pudb/remote.py
index 87796213..a3138824 100644
--- a/pudb/remote.py
+++ b/pudb/remote.py
@@ -243,7 +243,12 @@ def set_trace(
 
 
 def debug_remote_on_single_rank(func: Callable, comm: Any, rank: int = 0) -> None:
-    """Run a remote debugger on a single rank of an :mod:`mpi4py` application."""
+    """Run a remote debugger on a single rank of an `mpi4py` application.
+
+    :param func: the function to debug.
+    :param comm: An `mpi4py` communicator.
+    :param rank: The rank to debug. All other ranks will spin until this rank exits.
+    """
     if comm.rank == rank:
         dbg = debugger()
         try:

From 3663cecd342fa7bb465386f5bef2aa2de54172d7 Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 29 Dec 2021 12:35:19 +0100
Subject: [PATCH 08/14] a bit more text

---
 pudb/remote.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pudb/remote.py b/pudb/remote.py
index a3138824..e4ae36b9 100644
--- a/pudb/remote.py
+++ b/pudb/remote.py
@@ -244,10 +244,12 @@ def set_trace(
 
 def debug_remote_on_single_rank(func: Callable, comm: Any, rank: int = 0) -> None:
     """Run a remote debugger on a single rank of an `mpi4py` application.
+    `func` will be called on rank `rank` running in a :class:`RemoteDebugger`,
+    and will be called normally on all other ranks.
 
     :param func: the function to debug.
-    :param comm: An `mpi4py` communicator.
-    :param rank: The rank to debug. All other ranks will spin until this rank exits.
+    :param comm: an `mpi4py` communicator.
+    :param rank: the rank to debug. All other ranks will spin until this rank exits.
     """
     if comm.rank == rank:
         dbg = debugger()

From d00cfd52f63f70012ee107fa37e95d4ae873d957 Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 29 Dec 2021 19:10:04 +0100
Subject: [PATCH 09/14] add an mpi4py example

---
 examples/mpi4py-debug.py | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 examples/mpi4py-debug.py

diff --git a/examples/mpi4py-debug.py b/examples/mpi4py-debug.py
new file mode 100644
index 00000000..57521f7a
--- /dev/null
+++ b/examples/mpi4py-debug.py
@@ -0,0 +1,13 @@
+#!/usr/bin/env python
+
+from mpi4py import MPI
+from pudb.remote import debug_remote_on_single_rank
+
+
+def debugged_function(x):
+    y = x + fail  # noqa: F821
+    return y
+
+
+# debug this application on rank 0
+debug_remote_on_single_rank(MPI.COMM_WORLD, 0, debugged_function, 42)

From 063f7ad181b07ddb41ca94d46195e8a15972ba37 Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 29 Dec 2021 19:11:28 +0100
Subject: [PATCH 10/14] allow arguments to func, better doc, simplify

---
 pudb/remote.py | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/pudb/remote.py b/pudb/remote.py
index e4ae36b9..e29741c7 100644
--- a/pudb/remote.py
+++ b/pudb/remote.py
@@ -242,23 +242,19 @@ def set_trace(
     ).set_trace(frame)
 
 
-def debug_remote_on_single_rank(func: Callable, comm: Any, rank: int = 0) -> None:
-    """Run a remote debugger on a single rank of an `mpi4py` application.
-    `func` will be called on rank `rank` running in a :class:`RemoteDebugger`,
+def debug_remote_on_single_rank(comm: Any, rank: int, func: Callable, *args, **kwargs) -> None:
+    """Run a remote debugger on a single rank of an ``mpi4py`` application.
+    *func* will be called on rank *rank* running in a :class:`RemoteDebugger`,
     and will be called normally on all other ranks.
 
-    :param func: the function to debug.
-    :param comm: an `mpi4py` communicator.
+    :param comm: an ``mpi4py`` ``Comm`` object.
     :param rank: the rank to debug. All other ranks will spin until this rank exits.
+    :param func: the callable to debug.
+    :param args: the arguments passed to ``func``.
+    :param kwargs: the kwargs passed to ``func``.
     """
     if comm.rank == rank:
-        dbg = debugger()
-        try:
-            dbg.runcall(func)
-        except Exception:
-            from pudb import pm
-            pm()
-
+        debugger().runcall(func, *args, **kwargs)
     else:
         try:
             func()

From 0db05a9c83594a61e442998a77f8bce9cc119a74 Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 29 Dec 2021 19:14:36 +0100
Subject: [PATCH 11/14] clarify comment

---
 examples/mpi4py-debug.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/mpi4py-debug.py b/examples/mpi4py-debug.py
index 57521f7a..7ac4880b 100644
--- a/examples/mpi4py-debug.py
+++ b/examples/mpi4py-debug.py
@@ -9,5 +9,5 @@ def debugged_function(x):
     return y
 
 
-# debug this application on rank 0
+# debug 'debugged_function' on rank 0
 debug_remote_on_single_rank(MPI.COMM_WORLD, 0, debugged_function, 42)

From d1716c9d783f199ff45d9c1356af533d638cc40b Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 29 Dec 2021 19:17:55 +0100
Subject: [PATCH 12/14] more doc

---
 examples/mpi4py-debug.py | 5 +++++
 pudb/remote.py           | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/examples/mpi4py-debug.py b/examples/mpi4py-debug.py
index 7ac4880b..87395d0c 100644
--- a/examples/mpi4py-debug.py
+++ b/examples/mpi4py-debug.py
@@ -1,5 +1,10 @@
 #!/usr/bin/env python
 
+# Demonstrate on how to debug an mpi4py application.
+# Run this with 'mpirun -n 2 python mpi4py-debug.py'.
+# You can then attach to the debugger by running 'telnet 127.0.0.1 6899'
+# in another terminal.
+
 from mpi4py import MPI
 from pudb.remote import debug_remote_on_single_rank
 
diff --git a/pudb/remote.py b/pudb/remote.py
index e29741c7..e8b16894 100644
--- a/pudb/remote.py
+++ b/pudb/remote.py
@@ -242,7 +242,8 @@ def set_trace(
     ).set_trace(frame)
 
 
-def debug_remote_on_single_rank(comm: Any, rank: int, func: Callable, *args, **kwargs) -> None:
+def debug_remote_on_single_rank(comm: Any, rank: int, func: Callable,
+                                *args: Any, **kwargs: Any) -> None:
     """Run a remote debugger on a single rank of an ``mpi4py`` application.
     *func* will be called on rank *rank* running in a :class:`RemoteDebugger`,
     and will be called normally on all other ranks.

From 58e2d21f65bdcb99ff89beb8620c6bb4c16284c8 Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 29 Dec 2021 19:19:33 +0100
Subject: [PATCH 13/14] clarify comment

---
 examples/mpi4py-debug.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/examples/mpi4py-debug.py b/examples/mpi4py-debug.py
index 87395d0c..f3c7b396 100644
--- a/examples/mpi4py-debug.py
+++ b/examples/mpi4py-debug.py
@@ -1,9 +1,9 @@
 #!/usr/bin/env python
 
-# Demonstrate on how to debug an mpi4py application.
+# This example demonstrates how to debug an mpi4py application.
 # Run this with 'mpirun -n 2 python mpi4py-debug.py'.
 # You can then attach to the debugger by running 'telnet 127.0.0.1 6899'
-# in another terminal.
+# (when using the default pudb configuration) in another terminal.
 
 from mpi4py import MPI
 from pudb.remote import debug_remote_on_single_rank

From ff7f8e304e781fd30949eb49e019b2186b2c9b50 Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 29 Dec 2021 19:28:30 +0100
Subject: [PATCH 14/14] add missing args

---
 pudb/remote.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pudb/remote.py b/pudb/remote.py
index e8b16894..87c59246 100644
--- a/pudb/remote.py
+++ b/pudb/remote.py
@@ -258,7 +258,7 @@ def debug_remote_on_single_rank(comm: Any, rank: int, func: Callable,
         debugger().runcall(func, *args, **kwargs)
     else:
         try:
-            func()
+            func(*args, **kwargs)
         finally:
             from time import sleep
             while True: