Rubocop: Command line rubocop passes, precommit hook throws Style/FileName in Gemfile

[pmichna]

When I run rubocop in my project everything passes.

I have turned on the precommit hook with overcommit. When trying to commit I get:

Errors on lines you didn't modify:
/Users/Pawel/code/project/Gemfile:1:1: C: Style/FileName: Use snake_case for source file names.

Why are these two results different?

The output of rubocop -V:

$ rubocop -V
0.38.0 (using Parser 2.3.0.6, running on ruby 2.2.3 x86_64-darwin14)

$ overcommit -v
overcommit 0.32.0

The first line of Gemfile that is allegedly wrong:

source 'https://rubygems.org'

.rubocop.yml:

inherit_from: .rubocop_todo.yml

Rails:
  Enabled: true

AllCops:
  Include:
    - '**/Rakefile'
    - '**/config.ru'
  Exclude:
    - 'db/**/*'
    - 'config/**/*'
    - 'vendor/**/*'

.overcommit.yml:

PreCommit:
  RuboCop:
    enabled: true

[Drenmi]

Looking back at overcommit release 0.32.0, their Gemfile has RuboCop locked at:

gem 'rubocop', '0.37.2'

So this was likely fixed at some point between 0.37.2 and 0.38.0, and the fix should be to update to the latest overcommit.

[effkay]

Having a similar issue, on rubocop 0.43.0. Running rubocop manually works fine and does not show the error, but in Neovim with Neomake which automatically runs recognized linters as rubocop, I get the warning about snake_case in the Gemfile.

[jcoyne]

I'm also seeing this on 0.48.0

$ rubocop
Inspecting 23 files
CC.................C...

Offenses:
...
Gemfile:1:1: C: Style/FileName: The name of this source file (Gemfile) should use snake_case.
source 'https://rubygems.org'
^

[monfresh]

I was also seeing this with 0.49.1 for Capfile:

Capfile:1:1: C: The name of this source file (Capfile) should use snake_case.
# Load DSL and Setup Up Stages
^

Adding **/Capfile to the AllCops: Include: list fixed it.

[jonas054]

This behavior is so counter-intuitive it's funny. Capfile is a file type that's hard-coded to be inspected, but in Naming/FileName we skip inspection if a file is listed in AllCops: Include, because then you have okayed its name.

So add the file name under AllCops: Include if you want to exclude it from inspection by Naming/FileName.

[Confusion]

Just tripped over this after upgrading to 0.53.0. Thanks for the workaround @jonas054!