From 5ac6194c2b13856edd7e7bcaaa69a15519fd993e Mon Sep 17 00:00:00 2001
From: Hartley McGuire <skipkayhil@gmail.com>
Date: Tue, 5 Mar 2024 20:13:38 -0500
Subject: [ruby/rdoc] Fix ToRdoc generating incorrect {label,name}-lists

Previously, trying to round-trip label-list and name-lists with the
ToRdoc converter was not possible:

```ruby
doc = <<~RDOC
foo ::
bar ::
  hi
RDOC

markup = RDoc::Markup.parse(doc)
markup # => [doc: [list: NOTE [item: ["foo ", "bar"]; [para: "hi"]]]]

rt = RDoc::Markup::ToRdoc.new.convert(markup)
rt # => "foo\nbar:\n  hi\n\n"

rt_markup = RDoc::Markup.parse(rt)
rt_markup # => [doc: [para: "foo ", "bar:"], [verb: "hi\n"]]
```

This commit addresses the issue by fixing ToRdoc to generate output that
can be properly reparsed by RDoc. ToRdoc tests additionally needed to be
updated for the new output.

The old implementation of `accept_list_item_start` was copied to ToBs
because those tests did not pass with the new changes and I am
unfamiliar with the `backspace` format.

After:

```ruby
doc = <<~RDOC
foo ::
bar ::
  hi
RDOC

markup = RDoc::Markup.parse(doc)
markup # => [doc: [list: NOTE [item: ["foo ", "bar"]; [para: "hi"]]]]

rt = RDoc::Markup::ToRdoc.new.convert(markup)
rt # => "foo::\nbar::\n  hi\n\n"

rt_markup = RDoc::Markup.parse(rt)
rt_markup # => [doc: [list: NOTE [item: ["foo", "bar"]; [para: "hi"], blankline]]]
```

https://github.com/ruby/rdoc/commit/c6c51aa900
---
 lib/rdoc/markup/to_bs.rb   | 25 +++++++++++++++++++++++++
 lib/rdoc/markup/to_rdoc.rb | 14 +++++++++++---
 2 files changed, 36 insertions(+), 3 deletions(-)

(limited to 'lib')

diff --git a/lib/rdoc/markup/to_bs.rb b/lib/rdoc/markup/to_bs.rb
index f9b86487db..afd9d6e981 100644
--- a/lib/rdoc/markup/to_bs.rb
+++ b/lib/rdoc/markup/to_bs.rb
@@ -40,6 +40,31 @@ class RDoc::Markup::ToBs < RDoc::Markup::ToRdoc
     @res << "\n"
   end
 
+  ##
+  # Prepares the visitor for consuming +list_item+
+
+  def accept_list_item_start list_item
+    type = @list_type.last
+
+    case type
+    when :NOTE, :LABEL then
+      bullets = Array(list_item.label).map do |label|
+        attributes(label).strip
+      end.join "\n"
+
+      bullets << ":\n" unless bullets.empty?
+
+      @prefix = ' ' * @indent
+      @indent += 2
+      @prefix << bullets + (' ' * @indent)
+    else
+      bullet = type == :BULLET ? '*' :  @list_index.last.to_s + '.'
+      @prefix = (' ' * @indent) + bullet.ljust(bullet.length + 1)
+      width = bullet.length + 1
+      @indent += width
+    end
+  end
+
   ##
   # Turns on or off regexp handling for +convert_string+
 
diff --git a/lib/rdoc/markup/to_rdoc.rb b/lib/rdoc/markup/to_rdoc.rb
index 6929049582..88234f5096 100644
--- a/lib/rdoc/markup/to_rdoc.rb
+++ b/lib/rdoc/markup/to_rdoc.rb
@@ -145,11 +145,19 @@ class RDoc::Markup::ToRdoc < RDoc::Markup::Formatter
 
     case type
     when :NOTE, :LABEL then
-      bullets = Array(list_item.label).map do |label|
+      stripped_labels = Array(list_item.label).map do |label|
         attributes(label).strip
-      end.join "\n"
+      end
+
+      bullets = case type
+      when :NOTE
+        stripped_labels.map { |b| "#{b}::" }
+      when :LABEL
+        stripped_labels.map { |b| "[#{b}]" }
+      end
 
-      bullets << ":\n" unless bullets.empty?
+      bullets = bullets.join("\n")
+      bullets << "\n" unless stripped_labels.empty?
 
       @prefix = ' ' * @indent
       @indent += 2
-- 
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