Add documentation link to RuboCop diagnostics (#1111)

* add documentation link to rubocop diagnostics

* use real lsp protocl, not the vscode version

* test fixtures not being picked up?

* load rubocop cops into constant

Author: dleavitt

CONTRIBUTING.md

@@ -24,8 +24,10 @@ The test suite can be executed by running
 bin/test
 # or the spec reporter
 SPEC_REPORTER=1 bin/test
-# Warning are turned off by default. If you wish to see warnings use
+# Warnings are turned off by default. If you wish to see warnings use
 VERBOSE=1 bin/test
+# Run a single test like this: "bin/test my_test.rb test_name_regex", e.g.
+bin/test test/requests/diagnostics_expectations_test.rb test_diagnostics__def_bad_formatting
 ```
 
 ## Expectation testing
@@ -46,7 +48,7 @@ We define expectations as `.exp` files, of which there are two variants:
 To add a new test scenario
 
 1. Add a new fixture `my_fixture.rb` file under `test/fixtures`
-2. For applicable requests, add expectation files related to this fixutre. For example,
+2. For applicable requests, add expectation files related to this fixture. For example,
 `test/expectations/semantic_highlighting/my_fixture.exp.json`
 
 To add a new expectations test runner for a new request handler:

lib/ruby_lsp/requests/support/rubocop_diagnostic.rb

@@ -19,6 +19,12 @@ class RuboCopDiagnostic
           T::Hash[Symbol, Integer],
         )
 
+        # Cache cops to attach URLs to diagnostics. Only built-in cops for now.
+        COP_TO_DOC_URL = T.let(
+          RuboCop::Cop::Registry.global.to_h,
+          T::Hash[String, [T.class_of(RuboCop::Cop::Base)]],
+        )
+
         sig { params(offense: RuboCop::Cop::Offense, uri: URI::Generic).void }
         def initialize(offense, uri)
           @offense = offense
@@ -52,10 +58,16 @@ def to_lsp_diagnostic
 
           message += "\n\nThis offense is not auto-correctable.\n" unless @offense.correctable?
 
+          cop = COP_TO_DOC_URL[@offense.cop_name]&.first
+          if cop&.documentation_url
+            code_description = { href: cop.documentation_url }
+          end
+
           Interface::Diagnostic.new(
             message: message,
             source: "RuboCop",
             code: @offense.cop_name,
+            code_description: code_description,
             severity: severity,
             range: Interface::Range.new(
               start: Interface::Position.new(

test/expectations/code_actions/def_bad_formatting.exp.json

@@ -62,6 +62,9 @@
                         }
                     },
                     "code": "Layout/EmptyLines",
+                    "codeDescription": {
+                        "href": "https://docs.rubocop.org/rubocop/cops_layout.html#layoutemptylines"
+                    },
                     "severity": 3,
                     "source": "RuboCop"
                 },
@@ -111,6 +114,9 @@
                         }
                     },
                     "code": "Layout/IndentationWidth",
+                    "codeDescription": {
+                        "href": "https://docs.rubocop.org/rubocop/cops_layout.html#layoutindentationwidth"
+                    },
                     "severity": 3,
                     "source": "RuboCop"
                 }

test/expectations/diagnostics/def_bad_formatting.exp.json

@@ -62,6 +62,9 @@
       },
       "severity": 3,
       "code": "Style/FrozenStringLiteralComment",
+      "codeDescription": {
+        "href": "https://docs.rubocop.org/rubocop/cops_style.html#stylefrozenstringliteralcomment"
+      },
       "source": "RuboCop",
       "message": "Style/FrozenStringLiteralComment: Missing frozen string literal comment.",
       "data": {
@@ -111,6 +114,9 @@
       },
       "severity": 3,
       "code": "Layout/EmptyLinesAroundMethodBody",
+      "codeDescription": {
+        "href": "https://docs.rubocop.org/rubocop/cops_layout.html#layoutemptylinesaroundmethodbody"
+      },
       "source": "RuboCop",
       "message": "Layout/EmptyLinesAroundMethodBody: Extra empty line detected at method body beginning.",
       "data": {
@@ -160,6 +166,9 @@
       },
       "severity": 3,
       "code": "Layout/EmptyLines",
+      "codeDescription": {
+        "href": "https://docs.rubocop.org/rubocop/cops_layout.html#layoutemptylines"
+      },
       "source": "RuboCop",
       "message": "Layout/EmptyLines: Extra blank line detected.",
       "data": {
@@ -209,6 +218,9 @@
       },
       "severity": 3,
       "code": "Layout/IndentationWidth",
+      "codeDescription": {
+        "href": "https://docs.rubocop.org/rubocop/cops_layout.html#layoutindentationwidth"
+      },
       "source": "RuboCop",
       "message": "Layout/IndentationWidth: Use 2 (not 0) spaces for indentation.",
       "data": {

test/expectations/diagnostics/if_inside_else.exp.json

@@ -48,6 +48,9 @@
       },
       "severity": 3,
       "code": "Style/IfInsideElse",
+      "codeDescription": {
+        "href": "https://docs.rubocop.org/rubocop/cops_style.html#styleifinsideelse"
+      },
       "source": "RuboCop",
       "message": "Style/IfInsideElse: Convert `if` nested inside `else` to `elsif`.",
       "data": {

test/requests/diagnostics_expectations_test.rb

@@ -52,6 +52,7 @@ def map_diagnostics(diagnostics)
         source: "RuboCop",
         code: diagnostic["code"],
         severity: diagnostic["severity"],
+        code_description: diagnostic["codeDescription"],
         range: LanguageServer::Protocol::Interface::Range.new(
           start: LanguageServer::Protocol::Interface::Position.new(
             line: diagnostic["range"]["start"]["line"],