[ruby/yarp] fix: %w list spanning a heredoc

Two fixes were necessary:

- ensure we are handling newlines correctly
- accept two consecutive string tokens without a separator

https://github.com/ruby/yarp/commit/4e707937cb

Co-authored-by: Kevin Newton <kddnewton@gmail.com>

4 files changed, 48 insertions, 12 deletions

diff --git a/test/yarp/fixtures/spanning_heredoc.txt b/test/yarp/fixtures/spanning_heredoc.txt
index 5040840e76..1b17edac5d 100644
--- a/test/yarp/fixtures/spanning_heredoc.txt
+++ b/test/yarp/fixtures/spanning_heredoc.txt
@@ -23,3 +23,9 @@ pp <<-A, %Q[h\
 g
 A
 h]
+
+# ripper can't parse this successfully, though ruby runs it correctly
+pp <<-A, %w[j\
+i
+A
+j]
diff --git a/test/yarp/parse_test.rb b/test/yarp/parse_test.rb
index 1eb0033208..b288d597b2 100644
--- a/test/yarp/parse_test.rb
+++ b/test/yarp/parse_test.rb
@@ -77,7 +77,7 @@ class ParseTest < Test::Unit::TestCase
     # into a single token. See https://bugs.ruby-lang.org/issues/19838.
     #
     # Additionally, Ripper cannot parse the %w[] fixture in this file, so set ripper_should_parse to false.
-    ripper_should_match = false if relative == "spanning_heredoc.txt"
+    ripper_should_parse = false if relative == "spanning_heredoc.txt"
 
     define_method "test_filepath_#{relative}" do
       # First, read the source from the filepath. Use binmode to avoid converting CRLF on Windows,
diff --git a/test/yarp/snapshots/spanning_heredoc.txt b/test/yarp/snapshots/spanning_heredoc.txt
index 244ced125b..f948e1e9d3 100644
--- a/test/yarp/snapshots/spanning_heredoc.txt
+++ b/test/yarp/snapshots/spanning_heredoc.txt
@@ -1,6 +1,6 @@
-ProgramNode(164...448)(
+ProgramNode(164...541)(
   [],
-  StatementsNode(164...448)(
+  StatementsNode(164...541)(
     [CallNode(164...192)(
        nil,
        nil,
@@ -110,6 +110,29 @@ ProgramNode(164...448)(
        nil,
        0,
        "pp"
+     ),
+     CallNode(520...541)(
+       nil,
+       nil,
+       (520...522),
+       nil,
+       ArgumentsNode(523...541)(
+         [InterpolatedStringNode(523...527)(
+            (523...527),
+            [StringNode(535...537)(nil, (535...537), nil, "i\n")],
+            (537...539)
+          ),
+          ArrayNode(529...541)(
+            [StringNode(532...535)(nil, (532...535), nil, "j\\\n"),
+             StringNode(539...540)(nil, (539...540), nil, "j")],
+            (529...532),
+            (540...541)
+          )]
+       ),
+       nil,
+       nil,
+       0,
+       "pp"
      )]
   )
 )
diff --git a/yarp/yarp.c b/yarp/yarp.c
index 129a176dec..a4b1c9be3c 100644
--- a/yarp/yarp.c
+++ b/yarp/yarp.c
@@ -6942,9 +6942,19 @@ parser_lex(yp_parser_t *parser) {
                     yp_unescape_type_t unescape_type = lex_mode->as.list.interpolation ? YP_UNESCAPE_ALL : YP_UNESCAPE_MINIMAL;
                     size_t difference = yp_unescape_calculate_difference(parser, breakpoint, unescape_type, false);
 
-                    // If the result is an escaped newline, then we need to
-                    // track that newline.
-                    yp_newline_list_check_append(&parser->newline_list, breakpoint + difference - 1);
+                    // If the result is an escaped newline ...
+                    if (*(breakpoint + difference - 1) == '\n') {
+                        if (parser->heredoc_end) {
+                            // ... if we are on the same line as a heredoc, flush the heredoc and
+                            // continue parsing after heredoc_end.
+                            parser->current.end = breakpoint + difference;
+                            parser_flush_heredoc_end(parser);
+                            LEX(YP_TOKEN_STRING_CONTENT);
+                        } else {
+                            // ... else track the newline.
+                            yp_newline_list_append(&parser->newline_list, breakpoint + difference - 1);
+                        }
+                    }
 
                     breakpoint = yp_strpbrk(parser, breakpoint + difference, breakpoints, parser->end - (breakpoint + difference));
                     continue;
@@ -12098,12 +12108,9 @@ parse_expression_prefix(yp_parser_t *parser, yp_binding_power_t binding_power) {
             accept(parser, YP_TOKEN_WORDS_SEP);
 
             while (!match_any_type_p(parser, 2, YP_TOKEN_STRING_END, YP_TOKEN_EOF)) {
-                if (yp_array_node_size(array) == 0) {
-                    accept(parser, YP_TOKEN_WORDS_SEP);
-                } else {
-                    expect(parser, YP_TOKEN_WORDS_SEP, "Expected a separator for the strings in a `%w` list.");
-                    if (match_type_p(parser, YP_TOKEN_STRING_END)) break;
-                }
+                accept(parser, YP_TOKEN_WORDS_SEP);
+                if (match_type_p(parser, YP_TOKEN_STRING_END)) break;
+
                 expect(parser, YP_TOKEN_STRING_CONTENT, "Expected a string in a `%w` list.");
 
                 yp_token_t opening = not_provided(parser);