Fix multiline ERB comment parsing

lib/ruby_lsp/erb_document.rb

@@ -82,6 +82,7 @@ def initialize(source)
         @ruby = +"" #: String
         @current_pos = 0 #: Integer
         @inside_ruby = false #: bool
+        @inside_erb_comment = false #: bool
       end
 
       #: -> void
@@ -100,12 +101,16 @@ def scan_char
 
         case char
         when "<"
-          if next_char == "%"
+          if !@inside_erb_comment && next_char == "%"
             @inside_ruby = true
             @current_pos += 1
             push_char("  ")
 
-            if next_char == "=" && @source[@current_pos + 2] == "="
+            if next_char == "#"
+              @inside_erb_comment = true
+              @current_pos += 1
+              push_char(" ")
+            elsif next_char == "=" && @source[@current_pos + 2] == "="
               @current_pos += 2
               push_char("  ")
             elsif next_char == "=" || next_char == "-"
@@ -121,6 +126,7 @@ def scan_char
           if @inside_ruby && next_char == "%" &&
               @source[@current_pos + 2] == ">"
             @current_pos += 2
+            @inside_erb_comment = false
             push_char("   ")
             @inside_ruby = false
           else
@@ -130,9 +136,10 @@ def scan_char
           end
         when "%"
           if @inside_ruby && next_char == ">"
-            @inside_ruby = false
             @current_pos += 1
+            @inside_erb_comment = false
             push_char("  ")
+            @inside_ruby = false
           else
             push_char(
               char, #: as !nil
@@ -159,7 +166,10 @@ def scan_char
 
       #: (String char) -> void
       def push_char(char)
-        if @inside_ruby
+        if @inside_erb_comment
+          @ruby << " " * char.length
+          @host_language << " " * char.length
+        elsif @inside_ruby
           @ruby << char
           @host_language << " " * char.length
         else

test/erb_document_test.rb

@@ -73,6 +73,53 @@ def test_erb_document_handles_windows_newlines
     assert_equal("   \r\nbar   ", document.parse_result.source.source)
   end
 
+  def test_multiline_erb_comments_are_excluded_from_virtual_sources
+    source = +"<%# first line\ncomment_method(:argument)\n-%>\n<%= visible_call %>"
+    document = RubyLsp::ERBDocument.new(
+      source: source,
+      version: 1,
+      uri: URI("file:///foo.erb"),
+      global_state: @global_state,
+    )
+
+    document.parse!
+
+    expected_ruby = source.gsub(/[^\r\n]/, " ")
+    visible_call = "visible_call"
+    visible_call_start = source.index(visible_call)
+    expected_ruby[visible_call_start, visible_call.length] = visible_call
+
+    refute_predicate(document, :syntax_error?)
+    assert_equal(expected_ruby, document.parse_result.source.source)
+    assert_equal(source.gsub(/[^\r\n]/, " "), document.host_language_source)
+  end
+
+  def test_multiline_erb_comments_preserve_windows_newlines_and_resume_scanning
+    source = +"<%# first line\r\ncomment_method(:argument) %>\r\n<p>visible</p>\r\n<%= another_call %>"
+    document = RubyLsp::ERBDocument.new(
+      source: source,
+      version: 1,
+      uri: URI("file:///foo.erb"),
+      global_state: @global_state,
+    )
+
+    document.parse!
+
+    expected_ruby = source.gsub(/[^\r\n]/, " ")
+    another_call = "another_call"
+    another_call_start = source.index(another_call)
+    expected_ruby[another_call_start, another_call.length] = another_call
+
+    expected_host = source.gsub(/[^\r\n]/, " ")
+    visible_html = "<p>visible</p>"
+    visible_html_start = source.index(visible_html)
+    expected_host[visible_html_start, visible_html.length] = visible_html
+
+    refute_predicate(document, :syntax_error?)
+    assert_equal(expected_ruby, document.parse_result.source.source)
+    assert_equal(expected_host, document.host_language_source)
+  end
+
   def test_erb_syntax_error_does_not_cause_crash
     [
       "<%=",