gnu: ruby-rubocop: Update to 0.88.0.

* gnu/packages/patches/ruby-rubocop-break-dependency-cycle.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register patch.
* gnu/packages/ruby.scm (ruby-rubocop): Update to 0.88.0.
[origin]: Use git-fetch.  Apply the newly added patch.
[arguments]: Set #:test-target to "default".  Remove #:tests?, enabling tests.
[phases]{remove-problematic-tests, disable-bundler, set-home,
make-adoc-files-writable}: New phases.  Replace the 'replace-git-ls-files
phase.
[native-inputs]: Add ruby-bump, ruby-pry, ruby-rspec, ruby-test-queue,
ruby-webmock-2 and ruby-yard.
[propagated-inputs]: Remove ruby-powerpack and ruby-jaro-winkler.  Add
ruby-regexp-parser, ruby-rexml and ruby-rubocop-ast.

3 files changed, 160 insertions, 10 deletions

diff --git a/gnu/local.mk b/gnu/local.mk
index b3811a473f..e8915990bc 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1513,6 +1513,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/racket-store-checksum-override.patch	\
   %D%/packages/patches/retroarch-disable-online-updater.patch	\
   %D%/packages/patches/ruby-rack-ignore-failing-test.patch	\
+  %D%/packages/patches/ruby-rubocop-break-dependency-cycle.patch\
   %D%/packages/patches/ruby-sanitize-system-libxml.patch	\
   %D%/packages/patches/ruby-tzinfo-data-ignore-broken-test.patch\
   %D%/packages/patches/runc-CVE-2019-5736.patch			\
diff --git a/gnu/packages/patches/ruby-rubocop-break-dependency-cycle.patch b/gnu/packages/patches/ruby-rubocop-break-dependency-cycle.patch
new file mode 100644
index 0000000000..035a98fa33
--- /dev/null
+++ b/gnu/packages/patches/ruby-rubocop-break-dependency-cycle.patch
@@ -0,0 +1,101 @@
+From ff3f00b7f33332ebf1c3c05abc4a781684775b3c Mon Sep 17 00:00:00 2001
+From: Maxim Cournoyer <maxim.cournoyer@gmail.com>
+Date: Tue, 14 Jul 2020 11:50:12 -0400
+Subject: [PATCH] config: Drop rubocop-performance, rubocop-rspec requirements.
+
+This patch removes Rubocop extensions from Rubocop's closure to break
+a dependency cycle with itself.
+
+* .rubocop.yml: Remove rubocop-performance and rubocop-rspec and their
+corresponding directives.
+* .rubocop_todo.yml: Likewise.
+---
+ .rubocop.yml      | 15 ---------------
+ .rubocop_todo.yml | 44 --------------------------------------------
+ 2 files changed, 59 deletions(-)
+
+diff --git a/.rubocop.yml b/.rubocop.yml
+index 4f05d5be2..f12ef7c06 100644
+--- a/.rubocop.yml
++++ b/.rubocop.yml
+@@ -3,8 +3,6 @@
+ inherit_from: .rubocop_todo.yml
+ require:
+   - rubocop/cop/internal_affairs
+-  - rubocop-performance
+-  - rubocop-rspec
+ 
+ AllCops:
+   NewCops: enable
+@@ -106,16 +104,3 @@ Metrics/ClassLength:
+ Metrics/ModuleLength:
+   Exclude:
+     - 'spec/**/*.rb'
+-
+-RSpec/FilePath:
+-  Exclude:
+-    - spec/rubocop/formatter/junit_formatter_spec.rb
+-
+-RSpec/PredicateMatcher:
+-  EnforcedStyle: explicit
+-
+-RSpec/MessageSpies:
+-  EnforcedStyle: receive
+-
+-RSpec/NestedGroups:
+-  Max: 7
+diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
+index 3f72042d1..fa637cd42 100644
+--- a/.rubocop_todo.yml
++++ b/.rubocop_todo.yml
+@@ -24,47 +24,3 @@ Metrics/MethodLength:
+ # Configuration parameters: CountComments.
+ Metrics/ModuleLength:
+   Max: 132
+-
+-# Offense count: 10
+-RSpec/AnyInstance:
+-  Exclude:
+-    - 'spec/rubocop/cli_spec.rb'
+-    - 'spec/rubocop/cop/lint/duplicate_methods_spec.rb'
+-    - 'spec/rubocop/cop/team_spec.rb'
+-    - 'spec/rubocop/target_finder_spec.rb'
+-
+-# Offense count: 981
+-# Configuration parameters: Prefixes.
+-# Prefixes: when, with, without
+-RSpec/ContextWording:
+-  Enabled: false
+-
+-# Offense count: 3810
+-# Configuration parameters: Max.
+-RSpec/ExampleLength:
+-  Enabled: false
+-
+-# Offense count: 38
+-RSpec/ExpectOutput:
+-  Exclude:
+-    - 'spec/rubocop/cli/cli_auto_gen_config_spec.rb'
+-    - 'spec/rubocop/cli/cli_options_spec.rb'
+-    - 'spec/rubocop/config_spec.rb'
+-    - 'spec/rubocop/cop/cop_spec.rb'
+-    - 'spec/rubocop/formatter/disabled_config_formatter_spec.rb'
+-    - 'spec/rubocop/formatter/formatter_set_spec.rb'
+-    - 'spec/rubocop/options_spec.rb'
+-    - 'spec/rubocop/rake_task_spec.rb'
+-    - 'spec/rubocop/result_cache_spec.rb'
+-    - 'spec/rubocop/target_finder_spec.rb'
+-
+-# Offense count: 434
+-RSpec/MultipleExpectations:
+-  Max: 25
+-
+-# Offense count: 5
+-RSpec/SubjectStub:
+-  Exclude:
+-    - 'spec/rubocop/config_spec.rb'
+-    - 'spec/rubocop/formatter/json_formatter_spec.rb'
+-    - 'spec/rubocop/formatter/progress_formatter_spec.rb'
+-- 
+2.27.0
+
diff --git a/gnu/packages/ruby.scm b/gnu/packages/ruby.scm
index 0fae903592..8b87449d7d 100644
--- a/gnu/packages/ruby.scm
+++ b/gnu/packages/ruby.scm
@@ -6664,25 +6664,73 @@ run.")
 (define-public ruby-rubocop
   (package
     (name "ruby-rubocop")
-    (version "0.77.0")
+    (version "0.88.0")
     (source
      (origin
-       (method url-fetch)
-       (uri (rubygems-uri "rubocop" version))
+       (method git-fetch)               ;no tests in distributed gem
+       (uri (git-reference
+             (url "https://github.com/rubocop-hq/rubocop.git")
+             (commit (string-append "v" version))))
+       (file-name (git-file-name name version))
        (sha256
         (base32
-         "0m88b1bgbhmmbdnz2xv6n0il0j4q5qm9jbc0vf1zsaxmxqp06nx9"))))
+         "1d06893jp8pd85fvgp5d16vqcf31bafi430v4f4y746ihyvhzz5r"))
+       (patches (search-patches "ruby-rubocop-break-dependency-cycle.patch"))))
     (build-system ruby-build-system)
     (arguments
-     '(;; No included tests
-       #:tests? #f))
+     '(#:test-target "default"
+       #:phases
+       (modify-phases %standard-phases
+         (add-after 'unpack 'remove-problematic-tests
+           ;; These tests depend on Rubocop extensions, which cannot be
+           ;; included as they cause a dependency cycle with Rubocop itself.
+           (lambda _
+             (delete-file "spec/rubocop/config_loader_spec.rb")
+             (substitute* "Gemfile"
+               ((".*'rubocop-performance'.*") "")
+               ((".*'rubocop-rspec'.*") ""))
+             ;; Prevent "Unnecessary disabling of RSpec/* (unknown cop)"
+             ;; errors.
+             (substitute* (find-files "spec/rubocop/cop/" "_spec\\.rb$")
+               (("# (rubocop:(enable|disable) RSpec.*)" _ what)
+                (string-append "# Disabled: " what)))
+             #t))
+         (add-after 'unpack 'disable-bundler
+           (lambda _
+             (substitute* "Rakefile"
+               (("Bundler\\.setup.*") "nil\n"))
+             #t))
+         (replace 'replace-git-ls-files
+           (lambda _
+             (substitute* "rubocop.gemspec"
+               (("`git ls-files(.*)`" _ files)
+                (format #f "`find ~a -type f| sort`" files)))
+             #t))
+         (add-before 'check 'set-home
+           (lambda _
+             (setenv "HOME" (getcwd))
+             #t))
+         (add-before 'check 'make-adoc-files-writable
+           (lambda _
+             (let ((adoc-files (find-files "docs/modules/ROOT/pages"
+                                           "\\.adoc$")))
+               (for-each make-file-writable adoc-files))
+             #t)))))
+    (native-inputs
+     `(("ruby-bump" ,ruby-bump)
+       ("ruby-pry" ,ruby-pry)
+       ("ruby-rspec" ,ruby-rspec)
+       ("ruby-test-queue" ,ruby-test-queue)
+       ("ruby-webmock" ,ruby-webmock-2)
+       ("ruby-yard" ,ruby-yard)))
     (propagated-inputs
-     `(("ruby-parser" ,ruby-parser)
-       ("ruby-powerpack" ,ruby-powerpack)
+     `(("ruby-parallel" ,ruby-parallel)
+       ("ruby-parser" ,ruby-parser)
        ("ruby-rainbow" ,ruby-rainbow)
+       ("ruby-regexp-parser" ,ruby-regexp-parser)
+       ("ruby-rexml" ,ruby-rexml)
+       ("ruby-rubocop-ast" ,ruby-rubocop-ast)
        ("ruby-progressbar" ,ruby-progressbar)
-       ("ruby-parallel" ,ruby-parallel)
-       ("ruby-jaro-winkler" ,ruby-jaro-winkler)
        ("ruby-unicode-display-width" ,ruby-unicode-display-width)))
     (synopsis "Ruby code style checking tool")
     (description