Move away from the singleton approach and introduce Guard::Engine (#982)

* Move away from the singleton approach and introduce Guard::Engine
* Create a new Guardfile::Result class to hold the data from Guardfile evaluation
* Fix DslDescriber spec when using Unicode characters
* Improve internal structure further
* Allow to reset the scopes from the interactor

Signed-off-by: Rémy Coutable <remy@rymai.me>

.hound.yml

@@ -1,12 +1,13 @@
-fail_on_violations: true
+fail_on_violations: false
 
 rubocop:
   enabled: true
-  version: 0.75.0
+  version: 0.83.0
   config_file: .rubocop.yml
 
 reek:
   enabled: true
+  config_file: .reek.yml
 
 flog:
   enabled: true

.reek.yml

@@ -0,0 +1,80 @@
+---
+detectors:
+  UtilityFunction:
+    public_methods_only: true
+
+  BooleanParameter:
+    exclude:
+      - "Guard::Interactor#initialize"
+
+  FeatureEnvy:
+    exclude:
+      - "Guard::CLI#show"
+      - "Guard::CLI#notifiers"
+      - "Guard::Engine#_evaluate"
+      - "Guard::TestHelpers::Template::Session#match"
+      - "Guard::DslDescriber#show"
+      - "Guard::DslDescriber#list"
+
+  ControlParameter:
+    exclude:
+      - "Guard::Engine#interactor="
+      - "Guard::Runner#run"
+      - "stub_file"
+
+  InstanceVariableAssumption:
+    exclude:
+      - "Guard::Dsl"
+
+  NilCheck:
+    exclude:
+      - "Guard::Cli::Environments::ReadyOnly#start"
+      - "Guard::UI#clear"
+      - "Guard::DslDescriber#show"
+
+  NestedIterators:
+    exclude:
+      - "Guard::Dsl#self.cleanup_backtrace"
+      - "Guard::DslDescriber#show"
+
+  TooManyStatements:
+    exclude:
+      - "Guard::Dsl#evaluate"
+      - "Guard::Dsl#self.cleanup_backtrace"
+      - "Guard::Engine#_guardfile_deprecated_check"
+      - "Guard::Engine#_evaluate"
+      - "Guard::Engine#start"
+      - "Guard::Engine#pause"
+      - "Guard::Engine#stop"
+      - "Guard::Engine#_instantiate"
+      - "Guard::PluginUtil#plugin_class"
+      - "Guard::TestHelpers::Template::Session#_watches"
+
+  TooManyMethods:
+    exclude:
+      - "Guard::Engine"
+
+  IrresponsibleModule:
+    exclude:
+      - "Guard::Notifier"
+      - "Guard::Cli::Environments::Base"
+      - "Guard::Cli::Environments::ReadOnly"
+      - "Guard::Cli::Environments::Write"
+      - "Guard::Dsl"
+      - "Guard::Dummy"
+      - "Guard::Doe"
+      - "Guard::FooBar"
+      - "Guard::FooBaz"
+      - "Guard::TestHelper"
+      - "FakePry"
+      - "ApplicationController#respond"
+
+  UncommunicativeVariableName:
+    exclude:
+      - "ArubaAdapter"
+      - "Guard::Cli::Environments::ReadOnly"
+      - "Guard::Cli::Environments::Write"
+      - "Guard::Dsl#evaluate"
+      - "Guard::Engine#start"
+      - "Guard::PluginUtil#initialize_plugin"
+      - "Guard::PluginUtil#plugin_class"

.rspec

@@ -1,4 +1,3 @@
---fail-fast
 --format documentation
 --color
 --require spec_helper

.rubocop.yml

@@ -1,12 +1,12 @@
 AllCops:
-  TargetRubyVersion: 2.4
+  TargetRubyVersion: 2.5
   Exclude:
     - "vendor/**/*"
     - "db/schema.rb"
     - "tmp/**/*"
     - "Guardfile"
     - "config/Guardfile"
-  UseCache: false
+
 Style/CollectionMethods:
   Description: Preferred collection methods.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#map-find-select-reduce-size
@@ -17,6 +17,7 @@ Style/CollectionMethods:
     find: detect
     find_all: select
     reduce: inject
+
 Layout/DotPosition:
   Description: Checks the position of the dot in multi-line method calls.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#consistent-multi-line-chains
@@ -25,23 +26,28 @@ Layout/DotPosition:
   SupportedStyles:
   - leading
   - trailing
+
 Naming/FileName:
   Description: Use snake_case for source file names.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#snake-case-files
   Enabled: false
   Exclude: []
+
 Style/GuardClause:
   Description: Check for conditionals that can be replaced with guard clauses
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#no-nested-conditionals
   Enabled: false
   MinBodyLength: 1
+
 Style/IfUnlessModifier:
   Description: Favor modifier if/unless usage when you have a single-line body.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#if-as-a-modifier
   Enabled: false
+
 Style/OptionHash:
   Description: Don't use option hashes when you can use keyword arguments.
   Enabled: false
+
 Style/PercentLiteralDelimiters:
   Description: Use `%`-literal delimiters consistently
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#percent-literal-braces
@@ -56,6 +62,7 @@ Style/PercentLiteralDelimiters:
     "%w": "()"
     "%W": "()"
     "%x": "()"
+
 Naming/PredicateName:
   Description: Check the names of predicate methods.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#bool-methods-qmark
@@ -64,10 +71,11 @@ Naming/PredicateName:
   - is_
   - has_
   - have_
-  NamePrefixBlacklist:
+  ForbiddenPrefixes:
   - is_
   Exclude:
   - spec/**/*
+
 Style/RaiseArgs:
   Description: Checks the arguments passed to raise/fail.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#exception-class-messages
@@ -76,6 +84,7 @@ Style/RaiseArgs:
   SupportedStyles:
   - compact
   - exploded
+
 Style/SignalException:
   Description: Checks for proper usage of fail and raise.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#fail-method
@@ -85,6 +94,7 @@ Style/SignalException:
   - only_raise
   - only_fail
   - semantic
+
 Style/SingleLineBlockParams:
   Description: Enforces the names of some block params.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#reduce-blocks
@@ -96,11 +106,13 @@ Style/SingleLineBlockParams:
   - inject:
     - a
     - e
+
 Style/SingleLineMethods:
   Description: Avoid single-line methods.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#no-single-line-methods
   Enabled: false
   AllowIfMethodIsEmpty: true
+
 Style/StringLiterals:
   Description: Checks if uses of quotes match the configured preference.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#consistent-string-literals
@@ -109,6 +121,7 @@ Style/StringLiterals:
   SupportedStyles:
   - single_quotes
   - double_quotes
+
 Style/StringLiteralsInInterpolation:
   Description: Checks if uses of quotes inside expressions in interpolated strings
     match the configured preference.
@@ -117,6 +130,7 @@ Style/StringLiteralsInInterpolation:
   SupportedStyles:
   - single_quotes
   - double_quotes
+
 Style/TrailingCommaInArguments:
   Description: 'Checks for trailing comma in argument lists.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#no-trailing-array-commas'
@@ -126,6 +140,7 @@ Style/TrailingCommaInArguments:
   # - comma
   # - consistent_comma
   # - no_comma
+
 Style/TrailingCommaInHashLiteral:
   Description: 'Checks for trailing comma in hash literals.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#no-trailing-array-commas'
@@ -135,6 +150,7 @@ Style/TrailingCommaInHashLiteral:
   # - comma
   # - consistent_comma
   # - no_comma
+
 Style/TrailingCommaInArrayLiteral:
   Description: 'Checks for trailing comma in array literals.'
   StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#no-trailing-array-commas'
@@ -144,30 +160,36 @@ Style/TrailingCommaInArrayLiteral:
   # - comma
   # - consistent_comma
   # - no_comma
+
 Metrics/AbcSize:
   Description: A calculated magnitude based on number of assignments, branches, and
     conditions.
   Enabled: false
   Max: 15
+
 Metrics/ClassLength:
   Description: Avoid classes longer than 100 lines of code.
   Enabled: false
   CountComments: false
   Max: 100
+
 Metrics/ModuleLength:
   CountComments: false
   Max: 100
   Description: Avoid modules longer than 100 lines of code.
   Enabled: false
+
 Metrics/BlockLength:
   Exclude:
     - spec/**/*.rb
+
 Metrics/CyclomaticComplexity:
   Description: A complexity metric that is strongly correlated to the number of test
     cases needed to validate a method.
   Enabled: false
   Max: 6
-Metrics/LineLength:
+
+Layout/LineLength:
   Enabled: true
   Max: 125
   # To make it possible to copy or click on URIs in the code, we allow lines
@@ -184,92 +206,114 @@ Metrics/LineLength:
   # elements. Strings will be converted to Regexp objects. A line that matches
   # any regular expression listed in this option will be ignored by LineLength.
   IgnoredPatterns: []
+
 Metrics/MethodLength:
   Description: Avoid methods longer than 10 lines of code.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#short-methods
   Enabled: false
   CountComments: false
   Max: 10
+
 Metrics/ParameterLists:
   Description: Avoid parameter lists longer than three or four parameters.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#too-many-params
   Enabled: false
   Max: 5
   CountKeywordArgs: true
+
 Metrics/PerceivedComplexity:
   Description: A complexity metric geared towards measuring complexity for a human
     reader.
   Enabled: false
   Max: 7
+
 Lint/AssignmentInCondition:
   Description: Don't use assignment in conditions.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#safe-assignment-in-condition
   Enabled: false
   AllowSafeAssignment: true
+
 Style/InlineComment:
   Description: Avoid inline comments.
   Enabled: false
+
 Naming/AccessorMethodName:
   Description: Check the naming of accessor methods for get_/set_.
   Enabled: false
+
 Style/Alias:
   Description: Use alias_method instead of alias.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#alias-method
   Enabled: false
+
 Style/Documentation:
   Description: Document classes and non-namespace modules.
   Enabled: false
+
 Style/DoubleNegation:
   Description: Checks for uses of double negation (!!).
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#no-bang-bang
   Enabled: false
+
 Style/EachWithObject:
   Description: Prefer `each_with_object` over `inject` or `reduce`.
   Enabled: false
+
 Style/EmptyLiteral:
   Description: Prefer literals to Array.new/Hash.new/String.new.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#literal-array-hash
   Enabled: false
+
 Style/ModuleFunction:
   Description: Checks for usage of `extend self` in modules.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#module-function
   Enabled: false
+
 Style/OneLineConditional:
   Description: Favor the ternary operator(?:) over if/then/else/end constructs.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#ternary-operator
   Enabled: false
+
 Style/PerlBackrefs:
   Description: Avoid Perl-style regex back references.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#no-perl-regexp-last-matchers
   Enabled: false
+
 Style/Send:
   Description: Prefer `Object#__send__` or `Object#public_send` to `send`, as `send`
     may overlap with existing methods.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#prefer-public-send
   Enabled: false
+
 Style/SpecialGlobalVars:
   Description: Avoid Perl-style global variables.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#no-cryptic-perlisms
   Enabled: false
+
 Style/VariableInterpolation:
   Description: Don't interpolate global, instance and class variables directly in
     strings.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#curlies-interpolate
   Enabled: false
+
 Style/WhenThen:
   Description: Use when x then ... for one-line cases.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#one-line-cases
   Enabled: false
+
 Lint/EachWithObjectArgument:
   Description: Check for immutable argument given to each_with_object.
   Enabled: true
-Lint/HandleExceptions:
+
+Lint/SuppressedException:
   Description: Don't suppress exception.
   StyleGuide: https://github.com/bbatsov/ruby-style-guide#dont-hide-exceptions
   Enabled: false
+
 Lint/LiteralAsCondition:
   Description: Checks of literals used in conditions.
   Enabled: false
+
 Lint/LiteralInInterpolation:
   Description: Checks for literals used in interpolation.
   Enabled: false