(from https://github.com/nedbat/coveragepy/issues/1184)

This code runs the return statement on line 17 twice.  The second time, there is a "line" event and then a "return" event for that line.  But the first time, there is only a "return" event:

--- 8< -------------------------------
import linecache, sys

def trace(frame, event, arg):
    # The weird globals here is to avoid a NameError on shutdown...
    if frame.f_code.co_filename == globals().get("__file__"):
        lineno = frame.f_lineno
        print("{} {}: {}".format(event[:4], lineno, linecache.getline(__file__, lineno).rstrip()))
    return trace

def foo(x):
    if x:
        try:
            1/(x - 1)
        except ZeroDivisionError:
            pass

    return x

def test_foo():
    for i in range(2):
        foo(i)

print(sys.version)
sys.settrace(trace)
test_foo()
-----------------------------------------

I get this output with 3.10.0b3:

3.10.0b3 (default, Jun 18 2021, 06:43:38) [Clang 12.0.0 (clang-1200.0.32.29)]
call 19: def test_foo():
line 20:     for i in range(2):
line 21:         foo(i)
call 10: def foo(x):
line 11:     if x:
retu 17:     return x
line 20:     for i in range(2):
line 21:         foo(i)
call 10: def foo(x):
line 11:     if x:
line 12:         try:
line 13:             1/(x - 1)
exce 13:             1/(x - 1)
line 14:         except ZeroDivisionError:
line 15:             pass
line 17:     return x
retu 17:     return x
line 20:     for i in range(2):
retu 20:     for i in range(2):


Shouldn't there be a "line" event for both invocations?

Mark, please take a look as beta4 is this week

Gentle ping as beta 4 is in 2 days

Pablo, it seems: the 3.10 branch as for https://github.com/nedbat/coveragepy/issues/1184#issuecomment-873506523 still has this issue - I can reproduce one.

Ned, 

I am reviewing today PR 27068 and PR 27067 but it would be a great help if you can confirm that **both** work for your cases and don't break anything else

I can confirm that those two pull requests fix the problem reported here.

New changeset da6414f0acf5ec9ea3b07e4b3907bc49c2a61e2f by Mark Shannon in branch 'main':
bpo-44570: Fix line tracing for forwards jumps to duplicated tails (GH-27068)
https://github.com/python/cpython/commit/da6414f0acf5ec9ea3b07e4b3907bc49c2a61e2f

New changeset 9f2c63b258846a95393b556fee5e1090173ea717 by Mark Shannon in branch '3.10':
bpo-44570: Fix line tracing for forward jumps to duplicated tails (GH-27067)
https://github.com/python/cpython/commit/9f2c63b258846a95393b556fee5e1090173ea717

Awesome, thanks a lot for the quick resolution, Mark!