Support hover over gem name in Gemfile

Author: andyw8

Diff for: lib/ruby_lsp/listeners/hover.rb

@@ -92,6 +92,14 @@ def initialize(response_builder, global_state, uri, node_context, dispatcher, so
 
       #: (Prism::StringNode node) -> void
       def on_string_node_enter(node)
+        if @path && File.basename(@path) == GEMFILE_NAME
+          parent = @node_context.parent
+          if parent.is_a?(Prism::CallNode) && parent.name == :gem && parent.arguments&.arguments&.first == node
+            generate_gem_hover(parent)
+            return
+          end
+        end
+
         generate_heredoc_hover(node)
       end
 

Diff for: test/requests/hover_expectations_test.rb

@@ -273,7 +273,7 @@ class A
     end
   end
 
-  def test_hovering_over_gemfile_dependency
+  def test_hovering_over_gemfile_dependency_using_gem_call
     source = <<~RUBY
       gem 'rake'
     RUBY
@@ -295,6 +295,44 @@ def test_hovering_over_gemfile_dependency
     end
   end
 
+  def test_hovering_over_gemfile_dependency_using_gem_name
+    source = <<~RUBY
+      gem 'rake'
+    RUBY
+
+    # We need to pretend that Sorbet is not a dependency or else we can't properly test
+    with_server(source, URI("file:///Gemfile"), stub_no_typechecker: true) do |server, uri|
+      server.process_message(
+        id: 1,
+        method: "textDocument/hover",
+        params: { textDocument: { uri: uri }, position: { character: 5, line: 0 } },
+      )
+
+      response = server.pop_response.response
+
+      assert_includes(response.contents.value, "rake")
+    end
+  end
+
+  def test_hovering_over_gemfile_dependency_triggers_only_for_first_arg
+    source = <<~RUBY
+      gem 'rake', "~> 1.0"
+    RUBY
+
+    # We need to pretend that Sorbet is not a dependency or else we can't properly test
+    with_server(source, URI("file:///Gemfile"), stub_no_typechecker: true) do |server, uri|
+      server.process_message(
+        id: 1,
+        method: "textDocument/hover",
+        params: { textDocument: { uri: uri }, position: { character: 13, line: 0 } },
+      )
+
+      response = server.pop_response.response
+
+      assert_nil(response)
+    end
+  end
+
   def test_hovering_over_gemfile_dependency_with_missing_argument
     source = <<~RUBY
       gem()