Add Ruby linter with Steep (#4671)

* Add Ruby linter with Steep

Fixes #3254

* Run steep instead of using language server

LSP presents a few issues and this works around those.

* Work around Steep path issue

See https://github.com/soutaro/steep/pull/975

* Add simple tests for steep

* Add steep to supported tools

* Pass linter

* Add a comment regarding Steep's column counting

* Make lnum an integer

* Add Steep handler test

* Fix separator for Windows

* Escape Windows path separators for substitute()

* Use ALEInfo (I) group

* Use fnameescape instead of quotes

* Skip linting for files not under steep root

* Add and pass tests covering proper steep root lookup

* Fix separator discrepancy

* Use strict operators (match case)

* Fix ordering

* Use `is#` instead of `==#`

test/handler/test_steep_handler.vader

@@ -0,0 +1,100 @@
+Before:
+  runtime ale_linters/ruby/steep.vim
+
+After:
+  call ale#linter#Reset()
+
+Execute(The steep handler should parse lines correctly):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 400,
+  \     'col': 18,
+  \     'end_col': 45,
+  \     'text': 'Method parameters are incompatible with declaration `(untyped, untyped, *untyped, **untyped) { () -> untyped } -> untyped`',
+  \     'code': 'Ruby::MethodArityMismatch',
+  \     'type': 'E',
+  \   },
+  \   {
+  \     'lnum': 20,
+  \     'col': 9,
+  \     'end_col': 17,
+  \     'text': 'Cannot find implementation of method `::Frobz::FooBarBaz#method_name`',
+  \     'code': 'Ruby::MethodDefinitionMissing',
+  \     'type': 'W',
+  \   },
+  \   {
+  \     'lnum': 30,
+  \     'col': 9,
+  \     'end_col': 17,
+  \     'text': 'Cannot find implementation of method `::Frobz::FooBarBaz#method_name`',
+  \     'code': 'Ruby::MethodDefinitionMissing',
+  \     'type': 'I',
+  \   },
+  \   {
+  \     'lnum': 40,
+  \     'col': 9,
+  \     'end_col': 17,
+  \     'text': 'Cannot find implementation of method `::Frobz::FooBarBaz#method_name`',
+  \     'code': 'Ruby::MethodDefinitionMissing',
+  \     'type': 'I',
+  \   },
+  \ ],
+  \ ale_linters#ruby#steep#HandleOutput(347, [
+  \     '# Type checking files:',
+  \     '',
+  \     '...............................................................................................................................F..........F.F...F.',
+  \     '',
+  \     'lib/frobz/foobar_baz.rb:400:17: [error] Method parameters are incompatible with declaration `(untyped, untyped, *untyped, **untyped) { () -> untyped } -> untyped`',
+  \     '│ Diagnostic ID: Ruby::MethodArityMismatch',
+  \     '│',
+  \     '└         def frobz(obj, suffix, *args, &block)',
+  \     '                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~',
+  \     '',
+  \     'lib/frobz/foobar_baz.rb:20:8: [warning] Cannot find implementation of method `::Frobz::FooBarBaz#method_name`',
+  \     '│ Diagnostic ID: Ruby::MethodDefinitionMissing',
+  \     '│',
+  \     '└   class FooBarBaz',
+  \     '          ~~~~~~~~~',
+  \     '',
+  \     'lib/frobz/foobar_baz.rb:30:8: [information] Cannot find implementation of method `::Frobz::FooBarBaz#method_name`',
+  \     '│ Diagnostic ID: Ruby::MethodDefinitionMissing',
+  \     '│',
+  \     '└   class FooBarBaz',
+  \     '          ~~~~~~~~~',
+  \     '',
+  \     'lib/frobz/foobar_baz.rb:40:8: [hint] Cannot find implementation of method `::Frobz::FooBarBaz#method_name`',
+  \     '│ Diagnostic ID: Ruby::MethodDefinitionMissing',
+  \     '│',
+  \     '└   class FooBarBaz',
+  \     '          ~~~~~~~~~',
+  \     '',
+  \     'Detected 4 problems from 1 file',
+  \ ])
+
+Execute(The steep handler should handle when files are checked and no offenses are found):
+  AssertEqual
+  \ [],
+  \ ale_linters#ruby#steep#HandleOutput(347, [
+  \     '# Type checking files:',
+  \     '',
+  \     '.............................................................................................................................................',
+  \     '',
+  \     'No type error detected. 🧉',
+  \ ])
+
+Execute(The steep handler should handle when no files are checked):
+  AssertEqual
+  \ [],
+  \ ale_linters#ruby#steep#HandleOutput(347, [
+  \     '# Type checking files:',
+  \     '',
+  \     '',
+  \     '',
+  \     'No type error detected. 🧉',
+  \ ])
+
+Execute(The steep handler should handle empty output):
+  AssertEqual [], ale_linters#ruby#steep#HandleOutput(347, [''])
+  AssertEqual [], ale_linters#ruby#steep#HandleOutput(347, [])
+

test/linter/test_ruby_steep.vader

@@ -0,0 +1,69 @@
+" Author: Loic Nageleisen <https://github.com/lloeki>
+" Description: Tests for steep linter.
+Before:
+  call ale#assert#SetUpLinterTest('ruby', 'steep')
+
+  let g:ale_ruby_steep_executable = 'steep'
+
+After:
+  call ale#assert#TearDownLinterTest()
+
+Execute(Executable should default to steep):
+  call ale#test#SetFilename('../test-files/ruby/nested/foo/dummy.rb')
+  AssertLinter 'steep', ale#Escape('steep')
+  \   . ' check '
+  \   . ' dummy.rb'
+
+Execute(Should be able to set a custom executable):
+  let g:ale_ruby_steep_executable = 'bin/steep'
+
+  call ale#test#SetFilename('../test-files/ruby/nested/foo/dummy.rb')
+  AssertLinter 'bin/steep' , ale#Escape('bin/steep')
+  \   . ' check '
+  \   . ' dummy.rb'
+
+Execute(Setting bundle appends 'exec steep'):
+  let g:ale_ruby_steep_executable = 'path to/bundle'
+
+  call ale#test#SetFilename('../test-files/ruby/nested/foo/dummy.rb')
+  AssertLinter 'path to/bundle', ale#Escape('path to/bundle')
+  \   . ' exec steep'
+  \   . ' check '
+  \   . ' dummy.rb'
+
+Execute(should accept options):
+  let g:ale_ruby_steep_options = '--severity-level=hint'
+
+  call ale#test#SetFilename('../test-files/ruby/nested/foo/dummy.rb')
+  AssertLinter 'steep', ale#Escape('steep')
+  \   . ' check'
+  \   . ' --severity-level=hint'
+  \   . ' dummy.rb'
+
+Execute(Should not lint files out of steep root):
+  call ale#test#SetFilename('../test-files/ruby/nested/dummy.rb')
+  AssertLinter 'steep', ''
+
+Execute(Should lint files at top steep root):
+  call ale#test#SetFilename('../test-files/ruby/nested/foo/dummy.rb')
+  AssertLinter 'steep', ale#Escape('steep')
+  \   . ' check '
+  \   . ' dummy.rb'
+
+Execute(Should lint files below top steep root):
+  call ale#test#SetFilename('../test-files/ruby/nested/foo/one/dummy.rb')
+  AssertLinter 'steep', ale#Escape('steep')
+  \   . ' check '
+  \   . ' one' . (has('win32') ? '\' : '/') . 'dummy.rb'
+
+Execute(Should lint files at nested steep root):
+  call ale#test#SetFilename('../test-files/ruby/nested/foo/two/dummy.rb')
+  AssertLinter 'steep', ale#Escape('steep')
+  \   . ' check '
+  \   . ' dummy.rb'
+
+Execute(Should lint files below nested steep root):
+  call ale#test#SetFilename('../test-files/ruby/nested/foo/two/three/dummy.rb')
+  AssertLinter 'steep', ale#Escape('steep')
+  \   . ' check '
+  \   . ' three' . (has('win32') ? '\' : '/') . 'dummy.rb'