pdb: "debug print(" crashes with SyntaxError

[blueyed]

BPO	35931
Nosy	@blueyed, @ned-deily, @ambv, @zware, @eamanu, @miss-islington, @remilapeyre
PRs	bpo-35931: Gracefully handle SyntaxError in pdb debug command #11782 bpo-35931: Gracefully handle SyntaxError in pdb debug command #11782 [3.7] bpo-35931: Gracefully handle SyntaxError in pdb debug command (GH-11782) #11886 bpo-35931: Gracefully handle any exception in pdb debug command #12103 [3.7] bpo-35931: Gracefully handle any exception in pdb debug command (GH-12103) #12285

^{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 2019-03-12.04:02:55.136>
created_at = <Date 2019-02-07.16:02:51.406>
labels = ['3.7', '3.8', 'type-bug', 'library']
title = 'pdb: "debug print(" crashes with SyntaxError'
updated_at = <Date 2019-03-12.04:02:55.131>
user = 'https://github.com/blueyed'

bugs.python.org fields:

activity = <Date 2019-03-12.04:02:55.131>
actor = 'zach.ware'
assignee = 'none'
closed = True
closed_date = <Date 2019-03-12.04:02:55.136>
closer = 'zach.ware'
components = ['Library (Lib)']
creation = <Date 2019-02-07.16:02:51.406>
creator = 'blueyed'
dependencies = []
files = []
hgrepos = []
issue_num = 35931
keywords = ['patch', 'patch']
message_count = 12.0
messages = ['335025', '335643', '335645', '335646', '335647', '335649', '336862', '337575', '337576', '337714', '337716', '337717']
nosy_count = 7.0
nosy_names = ['blueyed', 'ned.deily', 'lukasz.langa', 'zach.ware', 'eamanu', 'miss-islington', 'remi.lapeyre']
pr_nums = ['11782', '11782', '11886', '12103', '12285']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue35931'
versions = ['Python 3.7', 'Python 3.8']

[blueyed]

debug print( will make pdb crash with a SyntaxError:

    % python -c '__import__("pdb").set_trace()'          
    --Return--
    > <string>(1)<module>()->None
    (Pdb) print(
    *** SyntaxError: unexpected EOF while parsing
    (Pdb) debug print(
    ENTERING RECURSIVE DEBUGGER
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/usr/lib64/python3.7/bdb.py", line 92, in trace_dispatch
        return self.dispatch_return(frame, arg)
      File "/usr/lib64/python3.7/bdb.py", line 151, in dispatch_return
        self.user_return(frame, arg)
      File "/usr/lib64/python3.7/pdb.py", line 293, in user_return
        self.interaction(frame, None)
      File "/usr/lib64/python3.7/pdb.py", line 352, in interaction
        self._cmdloop()
      File "/usr/lib64/python3.7/pdb.py", line 321, in _cmdloop
        self.cmdloop()
      File "/usr/lib64/python3.7/cmd.py", line 138, in cmdloop
        stop = self.onecmd(line)
      File "/usr/lib64/python3.7/pdb.py", line 418, in onecmd
        return cmd.Cmd.onecmd(self, line)
      File "/usr/lib64/python3.7/cmd.py", line 217, in onecmd
        return func(arg)
      File "/usr/lib64/python3.7/pdb.py", line 1099, in do_debug
        sys.call_tracing(p.run, (arg, globals, locals))
      File "/usr/lib64/python3.7/bdb.py", line 582, in run
        cmd = compile(cmd, "<string>", "exec")
      File "<string>", line 1
        print(
             ^
    SyntaxError: unexpected EOF while parsing

[eamanu]

ping reviewer :-)

I test this PR and work fine on Ubuntu 18.04

[miss-islington]

New changeset 4327705 by Miss Islington (bot) (Daniel Hahler) in branch 'master':
bpo-35931: Gracefully handle SyntaxError in pdb debug command (GH-11782)
4327705

[miss-islington]

New changeset 6f35219 by Miss Islington (bot) in branch '3.7':
bpo-35931: Gracefully handle SyntaxError in pdb debug command (GH-11782)
6f35219

[zware]

Thanks for the patch!

[blueyed]

Thanks for the review and backport!

[blueyed]

Re-opening: it currently still crashes with a NameError when using "debug doesnotexist", or "debug doesnotexist()".

Will create a new PR for this.

[blueyed]

Bumping.

The first (merged) patch is not sufficient, and causes even an API breakage, because it disallows passing in a code object (via compile()) anymore.

A better fix is waiting at #12103, and should also get backported to for 3.7.3 then (or the first backport being reverted).

[blueyed]

Example of the API breakage:

/opt/python/3.8-dev/lib/python3.8/pdb.py:321: in _cmdloop
    self.cmdloop()
/opt/python/3.8-dev/lib/python3.8/cmd.py:138: in cmdloop
    stop = self.onecmd(line)
/opt/python/3.8-dev/lib/python3.8/pdb.py:418: in onecmd
    return cmd.Cmd.onecmd(self, line)
/opt/python/3.8-dev/lib/python3.8/cmd.py:217: in onecmd
    return func(arg)
pdb.py:699: in do_debug
    return orig_do_debug(self, cmd)
/opt/python/3.8-dev/lib/python3.8/pdb.py:1097: in do_debug
    code = compile(arg, "<string>", "exec")
E   TypeError: compile() arg 1 must be a string, bytes or AST object

(via https://travis-ci.org/antocuni/pdb/jobs/504061679#L367)

[miss-islington]

New changeset 3e93643 by Miss Islington (bot) (Daniel Hahler) in branch 'master':
bpo-35931: Gracefully handle any exception in pdb debug command (GH-12103)
3e93643

[miss-islington]

New changeset 1c4580d by Miss Islington (bot) in branch '3.7':
[3.7] bpo-35931: Gracefully handle any exception in pdb debug command (GH-12103) (GH-12285)
1c4580d

[zware]

Thanks for catching that and fixing it before 3.7.3!