[debuginfo-tests][Dexter] Downgrade failure to delete working dir to warning not error

[jmorse]

Summary

On Windows, an error running the debugger typically leaves a process hanging around in the working directory. When Dexter exits, it can't then delete the working directory and produces an exception, masking the problem in the debugger. (This can be worked around by specifying --save-temps). Rather than hard-erroring, print a warning when we can't delete the working directory instead.

It'd be much better to improve our error handling, and make the WorkingDirectory class aware that something's wrong when it enters exit. However, this is something that's going to mask genuine errors and make everyones lives harder right now, so I think this non-ideal fix is important to get in first.

[Orlando]

debuginfo-tests/dexter/dex/utils/WorkingDirectory.py

45

In Warning.py there's a warning wrapper function warn(context, msg, flag=None). I think we should use that for consistency (it checks if the user has disabled warnings)?

[jmorse]

Sounds good, how's this?

[Orlando]

LGTM

[Orlando]

debuginfo-tests/dexter/dex/utils/WorkingDirectory.py

37–38

Is this used anywhere?

debuginfo-tests/dexter/dex/utils/WorkingDirectory.py

 # DExTer : Debugging Experience Tester
 # ~~~~~~   ~         ~~         ~   ~~
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 """Create/set a temporary working directory for some operations."""
 
 import os
 import shutil
 import tempfile
 import time
 
 from dex.utils.Exceptions import Error
-
+from dex.utils.Warning import warn
 
 class WorkingDirectory(object):
     def __init__(self, context, *args, **kwargs):
         self.context = context
         self.orig_cwd = os.getcwd()
 
         dir_ = kwargs.get('dir', None)
         if dir_ and not os.path.isdir(dir_):
             os.makedirs(dir_, exist_ok=True)
         self.path = tempfile.mkdtemp(*args, **kwargs)
 
     def __enter__(self):
         os.chdir(self.path)
         return self
 
     def __exit__(self, *args):
         os.chdir(self.orig_cwd)
         if self.context.options.save_temps:
             self.context.o.blue('"{}" left in place [--save-temps]\n'.format(
                 self.path))
             return
 
-        exception = AssertionError('should never be raised')
         for _ in range(100):
             try:
                 shutil.rmtree(self.path)
                 return
-            except OSError as e:
-                exception = e
+            except OSError:
                 time.sleep(0.1)
-        raise Error(exception)
+
+        warn(self.context, '"{}" left in place (couldn\'t delete)\n'.format(self.path))
+        return