Fix nested hash patterns from accidentally adding a then to their output.

Author: kddnewton

CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 
 ## [Unreleased]
 
+## [2.4.1] - 2022-05-10
+
+- Fix nested hash patterns from accidentally adding a `then` to their output.
+
 ## [2.4.0] - 2022-05-07
 
 ### Added
@@ -209,7 +213,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 
 - 🎉 Initial release! 🎉
 
-[unreleased]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.4.0...HEAD
+[unreleased]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.4.1...HEAD
+[2.4.1]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.4.0...v2.4.1
 [2.4.0]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.3.1...v2.4.0
 [2.3.1]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.3.0...v2.3.1
 [2.3.0]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.2.0...v2.3.0

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    syntax_tree (2.4.0)
+    syntax_tree (2.4.1)
 
 GEM
   remote: https://rubygems.org/

lib/syntax_tree/node.rb

@@ -5064,13 +5064,16 @@ def format(q)
       parts = keywords.map { |(key, value)| KeywordFormatter.new(key, value) }
       parts << KeywordRestFormatter.new(keyword_rest) if keyword_rest
 
+      nested = PATTERNS.include?(q.parent.class)
       contents = -> do
         q.group { q.seplist(parts) { |part| q.format(part, stackable: false) } }
 
         # If there isn't a constant, and there's a blank keyword_rest, then we
         # have an plain ** that needs to have a `then` after it in order to
         # parse correctly on the next parse.
-        q.text(" then") if !constant && keyword_rest && keyword_rest.value.nil?
+        if !constant && keyword_rest && keyword_rest.value.nil? && !nested
+          q.text(" then")
+        end
       end
 
       # If there is a constant, we're going to format to have the constant name
@@ -5097,7 +5100,7 @@ def format(q)
 
       # If there's only one pair, then we'll just print the contents provided
       # we're not inside another pattern.
-      if !PATTERNS.include?(q.parent.class) && parts.size == 1
+      if !nested && parts.size == 1
         contents.call
         return
       end

lib/syntax_tree/parser.rb

@@ -1671,9 +1671,15 @@ def on_heredoc_end(value)
     #     (nil | VarField) keyword_rest
     #   ) -> HshPtn
     def on_hshptn(constant, keywords, keyword_rest)
-      # Create an artificial VarField if we find an extra ** on the end
-      if !keyword_rest && (token = find_token(Op, "**", consume: false))
+      if keyword_rest
+        # We're doing this to delete the token from the list so that it doesn't
+        # confuse future patterns by thinking they have an extra ** on the end.
+        find_token(Op, "**")
+      elsif (token = find_token(Op, "**", consume: false))
         tokens.delete(token)
+
+        # Create an artificial VarField if we find an extra ** on the end. This
+        # means the formatting will be a little more consistent.
         keyword_rest = VarField.new(value: nil, location: token.location)
       end
 

lib/syntax_tree/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module SyntaxTree
-  VERSION = "2.4.0"
+  VERSION = "2.4.1"
 end

test/fixtures/hshptn.rb

@@ -66,3 +66,8 @@
 case foo
 in **nil
 end
+%
+case foo
+in bar, { baz:, **nil }
+in qux:
+end