IOError encountered opening file hidden by AttributeError

[asottile]

In GitLab by @dopplershift on Nov 21, 2016, 15:25

Currently if you hit a permission problem on a file (or at least that's my best guess of what went wrong on AppVeyor), you get:

Traceback (most recent call last):
  File "C:\Miniconda\envs\_test\Scripts\flake8-script.py", line 11, in <module>
    load_entry_point('flake8==3.2.1', 'console_scripts', 'flake8')()
  File "C:\Miniconda\envs\_test\lib\site-packages\flake8\main\cli.py", line 16, in main
    app.run(argv)
  File "C:\Miniconda\envs\_test\lib\site-packages\flake8\main\application.py", line 322, in run
    self._run(argv)
  File "C:\Miniconda\envs\_test\lib\site-packages\flake8\main\application.py", line 306, in _run
    self.run_checks()
  File "C:\Miniconda\envs\_test\lib\site-packages\flake8\main\application.py", line 243, in run_checks
    self.file_checker_manager.start(files)
  File "C:\Miniconda\envs\_test\lib\site-packages\flake8\checker.py", line 371, in start
    self.make_checkers(paths)
  File "C:\Miniconda\envs\_test\lib\site-packages\flake8\checker.py", line 285, in make_checkers
    if argument == filename or should_create_file_checker(filename)
  File "C:\Miniconda\envs\_test\lib\site-packages\flake8\checker.py", line 412, in __init__
    self.display_name = self.processor.filename
AttributeError: 'NoneType' object has no attribute 'filename'

This is due to the combination of setting FileChecker.display_name to self.processor.filename at https://gitlab.com/pycqa/flake8/blob/master/src/flake8/checker.py#L412 and the fact that FileChecker._make_processor() returns None in the error path at https://gitlab.com/pycqa/flake8/blob/master/src/flake8/checker.py#L412.

Not the cause of my problem, but it keeps me from ever seeing the error message from IOError.

[asottile]

In GitLab by @dopplershift on Nov 21, 2016, 15:25

Changed title: Poor message if → Poor message if{+ IOError encountered opening file+}

[asottile]

In GitLab by @dopplershift on Nov 21, 2016, 15:28

Changed title: {-Poor message if IOError encountered opening file-} → {+IOError encountered opening file hidden by AttributeError+}

[asottile]

In GitLab by @sigmavirus24 on Nov 23, 2016, 14:49

Mentioned in merge request !157

[asottile]

In GitLab by @sigmavirus24 on Nov 23, 2016, 14:50

Status changed to closed by commit b8ce133

[asottile]

In GitLab by @dopplershift on Nov 23, 2016, 15:21

Here's a patch I put together so that I could get flake8 to finally print out the message:

diff -rupN flake8-3.2.1/src/flake8/checker.py flake8-3.2.1-patched/src/flake8/checker.py
--- flake8-3.2.1/src/flake8/checker.py	2016-11-19 18:30:53.000000000 -0700
+++ flake8-3.2.1-patched/src/flake8/checker.py	2016-11-22 15:39:36.000000000 -0700
@@ -409,11 +409,16 @@ class FileChecker(object):
         self.checks = checks
         self.results = []
         self.processor = self._make_processor()
-        self.display_name = self.processor.filename
+        if self.processor:
+            self.display_name = self.processor.filename
+            lines = len(self.processor.lines)
+        else:
+            self.display_name = self.filename
+            lines = 0
         self.statistics = {
             'tokens': 0,
             'logical lines': 0,
-            'physical lines': len(self.processor.lines),
+            'physical lines': lines,
         }
 
     def _make_processor(self):
@@ -594,6 +599,11 @@ class FileChecker(object):
 
     def run_checks(self, results_queue, statistics_queue):
         """Run checks against the file."""
+        if not self.processor:
+            if results_queue is not None:
+                results_queue.put((self.filename, self.results))
+            return
+
         if self.processor.should_ignore_file():
             return

[asottile]

In GitLab by @dopplershift on Nov 23, 2016, 15:22

I'm not sure I see how !157 relates to this issue....

[asottile]

In GitLab by @sigmavirus24 on Nov 28, 2016, 12:59

Mentioned in commit asottile/flake8@b8ce133

[asottile]

In GitLab by @asottile on Nov 29, 2016, 08:11

I am in fact hitting this and fixing it as part of https://gitlab.com/pycqa/flake8/merge_requests/156

[asottile]

In GitLab by @alexwlchan on Nov 30, 2016, 13:04

An IOError seems like a plausible guess – I can reproduce this issue by asking flake8 to check a non-existent file:

$ flake8 thisfiledoesnotexist.py
Traceback (most recent call last):
  File "/Users/alexwlchan/.virtualenvs/specktre/bin/flake8", line 11, in <module>
    sys.exit(main())
  File "/Users/alexwlchan/.virtualenvs/specktre/lib/python3.5/site-packages/flake8/main/cli.py", line 16, in main
    app.run(argv)
  File "/Users/alexwlchan/.virtualenvs/specktre/lib/python3.5/site-packages/flake8/main/application.py", line 322, in run
    self._run(argv)
  File "/Users/alexwlchan/.virtualenvs/specktre/lib/python3.5/site-packages/flake8/main/application.py", line 306, in _run
    self.run_checks()
  File "/Users/alexwlchan/.virtualenvs/specktre/lib/python3.5/site-packages/flake8/main/application.py", line 243, in run_checks
    self.file_checker_manager.start(files)
  File "/Users/alexwlchan/.virtualenvs/specktre/lib/python3.5/site-packages/flake8/checker.py", line 371, in start
    self.make_checkers(paths)
  File "/Users/alexwlchan/.virtualenvs/specktre/lib/python3.5/site-packages/flake8/checker.py", line 275, in make_checkers
    for argument in paths
  File "/Users/alexwlchan/.virtualenvs/specktre/lib/python3.5/site-packages/flake8/checker.py", line 285, in <listcomp>
    if argument == filename or should_create_file_checker(filename)
  File "/Users/alexwlchan/.virtualenvs/specktre/lib/python3.5/site-packages/flake8/checker.py", line 412, in __init__
    self.display_name = self.processor.filename
AttributeError: 'NoneType' object has no attribute 'filename'

flake8 3.2.1, Python 3.5.2.

[asottile]

In GitLab by @sigmavirus24 on Dec 4, 2016, 09:41

mentioned in commit sigmavirus24/flake8@e4582ef

[asottile]

In GitLab by @fermulator on Jan 10, 2017, 17:38

I can confirm that patch noted in https://gitlab.com/pycqa/flake8/issues/268#note_18889944 solves the issue.

The input which caused the problem was doing something like this:
flake8 '' <real_file_path>

I had a script which was accidentally passing in two single quotes (due to empty string) as the first parameter (which was intended to be a list of args)

[asottile]

In GitLab by @sigmavirus24 on Jan 27, 2017, 13:29

This is fixed and will be released in 3.3.0

[asottile]

In GitLab by @sigmavirus24 on Jan 27, 2017, 13:29

closed