chore: import upstream snapshot with attribution

decoding/GAD/fairseq/pdb.py

@@ -0,0 +1,47 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import multiprocessing
+import os
+import pdb
+import sys
+
+
+__all__ = ["set_trace"]
+
+
+_stdin = [None]
+_stdin_lock = multiprocessing.Lock()
+try:
+    _stdin_fd = sys.stdin.fileno()
+except Exception:
+    _stdin_fd = None
+
+
+class MultiprocessingPdb(pdb.Pdb):
+    """A Pdb wrapper that works in a multiprocessing environment.
+
+    Usage: `from fairseq import pdb; pdb.set_trace()`
+    """
+
+    def __init__(self):
+        pdb.Pdb.__init__(self, nosigint=True)
+
+    def _cmdloop(self):
+        stdin_bak = sys.stdin
+        with _stdin_lock:
+            try:
+                if _stdin_fd is not None:
+                    if not _stdin[0]:
+                        _stdin[0] = os.fdopen(_stdin_fd)
+                    sys.stdin = _stdin[0]
+                self.cmdloop()
+            finally:
+                sys.stdin = stdin_bak
+
+
+def set_trace():
+    pdb = MultiprocessingPdb()
+    pdb.set_trace(sys._getframe().f_back)