Style/SpecialGlobalVars auto-gen-config behaviour change

[madwort]

In the process of tidying up an old codebase, have fixed some instances of Style/SpecialGlobalVars offenses but have more that I want to ignore with --auto-gen-config. v0.35.1 put this in ~/.rubocop_todo.yml:

Style/SpecialGlobalVars:
  Exclude:
    - 'filename.rb' # file with offenses in

as of git version 1716abb rubocop creates this instead:

Style/SpecialGlobalVars:
  EnforcedStyle: use_perl_names

which means that when I run rubocop I get alerted to the files that I've already fixed the offense in & breaks my incremental improvement workflow.

[alexdowad]

Does it make a difference if you delete the .rubocop_todo.yml file before regenerating it?

[madwort]

no, deleting .rubocop_todo.yml doesn't make a difference.

Now that I test it a bit more I realise that I'm having this issue with several cops so maybe there's something else going on (my expected workflow is to run auto-gen-config to allow me to ignore all cops, then selectively enable & fix). The other cops are:

• Style/WordArray
• Style/GuardClause
• Style/ConditionalAssignment

[madwort]

Style/WordArray may have changed its configuration in a similar way to Style/SpecialGlobalVars by adding EnforcedStyle: percent, but the other two are still only producing Exclude: filename.rb directives in the TODO file.

[alexdowad]

All those cops have changed recently.

[alexdowad]

Can you give a standalone file which I can run rubocop --auto-gen-config on to reproduce this?

[madwort]

ok, for Style/SpecialGlobalVars create this simple file:

echo $ERROR_INFO
echo $!

• run rubocop; line 2 fails
• run --auto-gen-config then run rubocop, line 1 fails
• expected behaviour: run --auto-gen-config, run rubocop, file passes.

[alexdowad]

Awesome, with repro this should be easy to debug.

[alexdowad]

I have a fix for this. Do you have a sample showing the same problem with WordArray, etc.?

[madwort]

Just been trying to get a good sample for GuardClause but put in its own thread, maybe it should be here? #2557

[jonas054]

No, it's better to keep it in a separate issue. I've answered there and I think it's not the same problem.

[madwort]

Fixed for the test case, but still broken for a different test case (sorry!):

test_varnames1.rb: $!
test_varnames2.rb: $ERROR_INFO

$ bundle exec rubocop  test_varnames1.rb test_varnames2.rb --auto-gen-config ; bundle exec rubocop test_varnames1.rb test_varnames2.rb 
warning: parser/current is loading parser/ruby22, which recognizes
warning: 2.2.4-compliant syntax, but you are running 2.2.2.
warning: please see https://github.com/whitequark/parser#compatibility-with-ruby-mri.
Inspecting 2 files
C.

Offenses:

test_varnames1.rb:1:1: C: Prefer $ERROR_INFO from the stdlib 'English' module over $!.
$!
^^

2 files inspected, 1 offense detected
Created .rubocop_todo.yml.
Run `rubocop --config .rubocop_todo.yml`, or add `inherit_from: .rubocop_todo.yml` in a .rubocop.yml file.
warning: parser/current is loading parser/ruby22, which recognizes
warning: 2.2.4-compliant syntax, but you are running 2.2.2.
warning: please see https://github.com/whitequark/parser#compatibility-with-ruby-mri.
Inspecting 2 files
C.

Offenses:

test_varnames1.rb:1:1: C: Prefer $ERROR_INFO from the stdlib 'English' module over $!.
$!
^^

2 files inspected, 1 offense detected

$ cat .rubocop_todo.yml 
# This configuration was generated by
# `rubocop --auto-gen-config`
# on 2015-12-31 12:02:32 +0000 using RuboCop version 0.35.1.
# The point is for the user to remove these configuration records
# one by one as the offenses are removed from the code base.
# Note that changes in the inspected code, or installation of new
# versions of RuboCop, may require this file to be generated again.

# Offense count: 1
# Cop supports --auto-correct.
# Configuration parameters: SupportedStyles.
# SupportedStyles: use_perl_names, use_english_names
Style/SpecialGlobalVars:
  EnforcedStyle: use_english_names

tested with bc3e40a

[alexdowad]

I caused that bug in 5673c6f. Looking for the best way to fix it.

[alexdowad]

My open PR has a fix.