dev server autoreload: OSError: [Errno 2] No such file or directory

[Collin Anderson]

on django 1.7, sometimes, when I'm saving a file, I'll get this error:

  File "/home/collin/saintmarys/django/core/management/base.py", line 363, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/collin/saintmarys/django/core/management/base.py", line 412, in execute
    output = self.handle(*args, **options)
  File "/home/collin/saintmarys/django/core/management/commands/runserver.py", line 80, in handle
    self.run(**options)
  File "/home/collin/saintmarys/django/core/management/commands/runserver.py", line 89, in run
    autoreload.main(self.inner_run, None, options)
  File "/home/collin/saintmarys/django/utils/autoreload.py", line 324, in main
    reloader(wrapped_main_func, args, kwargs)
  File "/home/collin/saintmarys/django/utils/autoreload.py", line 290, in python_reloader
    reloader_thread()
  File "/home/collin/saintmarys/django/utils/autoreload.py", line 266, in reloader_thread
    change = fn()
  File "/home/collin/saintmarys/django/utils/autoreload.py", line 204, in code_changed
    stat = os.stat(filename)
OSError: [Errno 2] No such file or directory: '/home/collin/saintmarys/main/views.py'

This never happened to me when editing python files on django 1.6. Would it make sense to catch this error and reload when this happens?

[Tim Graham]

Seems reasonable. I guess we'd just make this modification?

try:
    state = os.stat(filename)
except OSError:
    return I18N_MODIFIED if filename.endswith('.mo') else FILE_MODIFIED

[Collin Anderson]

Yup, that works for me. I guess it's actually pretty easy to reproduce: simply delete the file.

I assume it's another regression from _cached_filenames.

[Tim Graham]

Here is an actual patch. I used the tutorial and make a request to /polls/, then deleted polls/views.py, but the server didn't reload nor was there an error, so I'm not sure about testing it. I guess writing a test probably isn't feasible but let me know if you have an idea for that.

[Collin Anderson]

I just tried the tutorial also. If I install inotify, things work fine, but when inotify is not installed, I get this issue when deleting polls/views.py.

[Collin Anderson]

Actually, I have a feeling this code might not work correctly in the .mo case, but I don't use .mo files.

[Tim Graham]

Maybe Claude can look at the issue as he's worked on this code more than I.

[Hiroki Kiyohara]

It's regression caused by this ticket https://code.djangoproject.com/ticket/9722
and not so difficult (Of cause, I don't blame anybody).

And the reason is that the _cached_filenames stores file names even if some files are deleted:

• Lack of codes to clean up deleted files from _cached_filenames
• the sys.modules provides modules which is already deleted. so it's difficult to notice the deletion by '_cached_modules == set(sys.modules.values()).

By Timo's patch, os.stat causes OSError every time and the error will be globed.
(I'm not sure about OSErrors provided by os.stat, but it's not good to glob errors blindly)

[Hiroki Kiyohara]

This is the one.

[Tim Graham]

I'm trying to write a test.

[Tim Graham]

​PR

[Claude Paroz]

Thanks for caring for this issue, I was a bit short of time.

[Tim Graham <timograham@…>]

In b8cb5ba7081388ef38eccdf8e826747ad3a67e66:

Fixed #23083 -- Fixed runserver reloading when deleting a file.

Thanks Collin Anderson for the report and hirokiky for the fix.

[Tim Graham <timograham@…>]

In 4f8a5bd8d0f14280b25e4389b881f9f719159c38:

[1.7.x] Fixed #23083 -- Fixed runserver reloading when deleting a file.

Thanks Collin Anderson for the report and hirokiky for the fix.

Backport of b8cb5ba708 from master

[Tim Graham <timograham@…>]

In 57d2b3f2a7e5a7fafb99efc9d93e67bc98feea1b:

Fixed bad usage of rstrip() that caused test failure.

If the temporary file name contained a p or y as its last
characters, it would be stripped. refs #23083.

[Tim Graham <timograham@…>]

In d1c08d4758998318eb1a881a3963b63bc89435b8:

[1.7.x] Fixed bad usage of rstrip() that caused test failure.

If the temporary file name contained a p or y as its last
characters, it would be stripped. refs #23083.

Backport of 57d2b3f2a7 from master