work around frame.f_lineno being None sometimes

distributed/profile.py

@@ -27,6 +27,8 @@
 from __future__ import annotations
 
 import bisect
+import dis
+import itertools
 import linecache
 import sys
 import threading
@@ -41,6 +43,31 @@
 from distributed.metrics import time
 from distributed.utils import color_of
 
+if sys.version_info >= (3, 10):
+    _pairwise = itertools.pairwise
+else:
+
+    def _pairwise(iterable):
+        "s -> (s0,s1), (s1,s2), (s2, s3), ..."
+        a, b = itertools.tee(iterable)
+        next(b, None)
+        return zip(a, b)
+
+
+def _f_lineno(frame):
+    f_lineno = frame.f_lineno
+    if f_lineno is not None:
+        return f_lineno
+
+    f_lasti = frame.f_lasti
+    for (_, prev_line), (start, last_line) in _pairwise(
+        dis.findlinestarts(frame.f_code)
+    ):
+        if f_lasti < start:
+            return prev_line
+
+    return last_line
+
 
 def identifier(frame):
     """A string identifier from a frame
@@ -62,18 +89,20 @@ def identifier(frame):
 def repr_frame(frame):
     """Render a frame as a line for inclusion into a text traceback"""
     co = frame.f_code
-    text = f'  File "{co.co_filename}", line {frame.f_lineno}, in {co.co_name}'
-    line = linecache.getline(co.co_filename, frame.f_lineno, frame.f_globals).lstrip()
+    f_lineno = _f_lineno(frame)
+    text = f'  File "{co.co_filename}", line {f_lineno}, in {co.co_name}'
+    line = linecache.getline(co.co_filename, f_lineno, frame.f_globals).lstrip()
     return text + "\n\t" + line
 
 
 def info_frame(frame):
     co = frame.f_code
-    line = linecache.getline(co.co_filename, frame.f_lineno, frame.f_globals).lstrip()
+    f_lineno = _f_lineno(frame)
+    line = linecache.getline(co.co_filename, f_lineno, frame.f_globals).lstrip()
     return {
         "filename": co.co_filename,
         "name": co.co_name,
-        "line_number": frame.f_lineno,
+        "line_number": f_lineno,
         "line": line,
     }