pdb: "until" does not step over a list comprehension with a breakpoint set on it

Bug report

When a breakpoint is set on a line that holds a list comprehension (or any
single-line loop), the until command stops on that same line again on every
iteration instead of moving past it.

Reproduction:

# repro.py
def f():
    lst = [i for i in range(10)]
    for i in lst: pass

f()

$ python -m pdb repro.py
> repro.py(1)<module>()
-> def f():
(Pdb) break 2
Breakpoint 1 at repro.py:2
(Pdb) continue
> repro.py(2)f()
-> lst = [i for i in range(10)]
(Pdb) until
> repro.py(2)f()
-> lst = [i for i in range(10)]
(Pdb) until
> repro.py(2)f()
-> lst = [i for i in range(10)]

until keeps stopping on line 2, once per comprehension element.

Expected: until moves past the comprehension to the next line, the way next
and step already do (gh-136057, gh-136160). This also matches gdb, which
pdb's until is borrowed from: there, until steps past a single-line loop
to the next line even with a breakpoint set on it, instead of stopping on each
iteration.

I have a small fix for this and can open a PR.

Linked PRs

• gh-152374

Inizia dal punto di ingresso di pdb e riproduci il comportamento usando repro.py, impostando un breakpoint sulla riga della list comprehension ed eseguendo until ripetutamente. Confronta until con next e step, come descritto nell’issue. Il lavoro è completato quando until passa alla riga successiva invece di fermarsi su ogni elemento della comprehension; un PR collegato è già registrato.