Pdb does not correclty restart the target if it changes the current directory

[hexagonrecursion]

BPO	42383
Nosy	@gvanrossum, @hexagonrecursion
PRs	bpo-42384: pdb: correctly populate sys.path[0] #23338 bpo-42383: pdb: do not fail to restart the target if the current directory changed #23412 [3.9] bpo-42383: pdb: do not fail to restart the target if the current directory changed (GH-23412) #24322 [3.8] bpo-42383: pdb: do not fail to restart the target if the current directory changed (GH-23412) #24323

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2021-01-26.15:58:50.341>
created_at = <Date 2020-11-17.07:26:31.650>
labels = ['3.8', 'type-bug', 'library', '3.9', '3.10']
title = 'Pdb does not correclty restart the target if it changes the current directory'
updated_at = <Date 2021-01-26.15:58:50.341>
user = 'https://github.com/hexagonrecursion'

bugs.python.org fields:

activity = <Date 2021-01-26.15:58:50.341>
actor = 'gvanrossum'
assignee = 'none'
closed = True
closed_date = <Date 2021-01-26.15:58:50.341>
closer = 'gvanrossum'
components = ['Library (Lib)']
creation = <Date 2020-11-17.07:26:31.650>
creator = 'hexagonrecursion'
dependencies = []
files = []
hgrepos = []
issue_num = 42383
keywords = ['patch']
message_count = 5.0
messages = ['381213', '381216', '385665', '385722', '385723']
nosy_count = 2.0
nosy_names = ['gvanrossum', 'hexagonrecursion']
pr_nums = ['23338', '23412', '24322', '24323']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue42383'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']

[hexagonrecursion]

This was mentioned in bpo-31121, but I believe this deserves its own separate issue. If the debug target is specified using a relative path and later the current directory is changed, pdb tries to search for the target in the new current directory. This currently causes pdb to be unable to exit, which is what bpo-31121 and bpo-14743 are about, but even if they are fixed we would still be left with pdb exiting instead of restarting the target. This issues is about the latter.

To reproduce (same as bpo-31121):

$ mkdir foo
$ cat > foo/script.py
import os
os.chdir('foo')
$ python3 -m pdb foo/script.py 
> /home/user/foo/script.py(1)<module>()
-> import os
(Pdb) c
The program finished and will be restarted
Traceback (most recent call last):
  File "/usr/lib64/python3.8/pdb.py", line 1704, in main
    pdb._runscript(mainpyfile)
  File "/usr/lib64/python3.8/pdb.py", line 1570, in _runscript
    with io.open_code(filename) as fp:
FileNotFoundError: [Errno 2] No such file or directory: 'foo/script.py'
Uncaught exception. Entering post mortem debugging
Running 'cont' or 'step' will restart the program
> /usr/lib64/python3.8/pdb.py(1570)_runscript()
-> with io.open_code(filename) as fp:

[hexagonrecursion]

I'm working on fixing this

[gvanrossum]

New changeset 501d4a5 by Andrey Bienkowski in branch 'master':
bpo-42383: pdb: do not fail to restart the target if the current directory changed (bpo-23412)
501d4a5

[gvanrossum]

New changeset f8cfe54 by Andrey Bienkowski in branch '3.9':
[3.9] bpo-42383: pdb: do not fail to restart the target if the current directory changed (GH-23412) (bpo-24322)
f8cfe54

[gvanrossum]

New changeset d863dee by Andrey Bienkowski in branch '3.8':
[3.8] bpo-42383: pdb: do not fail to restart the target if the current directory changed (GH-23412) (bpo-24323)
d863dee