From 30038656aa3a4931abefd99b8166c26599d168fd Mon Sep 17 00:00:00 2001
From: Kevin Newton <kddnewton@gmail.com>
Date: Fri, 4 Oct 2024 13:57:14 -0400
Subject: [PATCH] Fix intermediate array off-by-one error

Co-authored-by: Adam Hess <HParker@github.com>
---
 iseq.c                          | 51 ++++++++++++++++++++++++++++++---
 prism_compile.c                 |  2 ++
 test/ruby/test_compile_prism.rb |  5 +++-
 3 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/iseq.c b/iseq.c
index 3d18fb597a..a60228c8e5 100644
--- a/iseq.c
+++ b/iseq.c
@@ -1569,6 +1569,48 @@ iseqw_s_compile(int argc, VALUE *argv, VALUE self)
     return iseqw_s_compile_parser(argc, argv, self, rb_ruby_prism_p());
 }
 
+/*
+ *  call-seq:
+ *     InstructionSequence.compile_parsey(source[, file[, path[, line[, options]]]]) -> iseq
+ *
+ *  Takes +source+, which can be a string of Ruby code, or an open +File+ object.
+ *  that contains Ruby source code. It parses and compiles using parse.y.
+ *
+ *  Optionally takes +file+, +path+, and +line+ which describe the file path,
+ *  real path and first line number of the ruby code in +source+ which are
+ *  metadata attached to the returned +iseq+.
+ *
+ *  +file+ is used for `__FILE__` and exception backtrace. +path+ is used for
+ *  +require_relative+ base. It is recommended these should be the same full
+ *  path.
+ *
+ *  +options+, which can be +true+, +false+ or a +Hash+, is used to
+ *  modify the default behavior of the Ruby iseq compiler.
+ *
+ *  For details regarding valid compile options see ::compile_option=.
+ *
+ *     RubyVM::InstructionSequence.compile_parsey("a = 1 + 2")
+ *     #=> <RubyVM::InstructionSequence:<compiled>@<compiled>>
+ *
+ *     path = "test.rb"
+ *     RubyVM::InstructionSequence.compile_parsey(File.read(path), path, File.expand_path(path))
+ *     #=> <RubyVM::InstructionSequence:<compiled>@test.rb:1>
+ *
+ *     file = File.open("test.rb")
+ *     RubyVM::InstructionSequence.compile_parsey(file)
+ *     #=> <RubyVM::InstructionSequence:<compiled>@<compiled>:1>
+ *
+ *     path = File.expand_path("test.rb")
+ *     RubyVM::InstructionSequence.compile_parsey(File.read(path), path, path)
+ *     #=> <RubyVM::InstructionSequence:<compiled>@/absolute/path/to/test.rb:1>
+ *
+ */
+static VALUE
+iseqw_s_compile_parsey(int argc, VALUE *argv, VALUE self)
+{
+    return iseqw_s_compile_parser(argc, argv, self, false);
+}
+
 /*
  *  call-seq:
  *     InstructionSequence.compile_prism(source[, file[, path[, line[, options]]]]) -> iseq
@@ -1589,19 +1631,19 @@ iseqw_s_compile(int argc, VALUE *argv, VALUE self)
  *
  *  For details regarding valid compile options see ::compile_option=.
  *
- *     RubyVM::InstructionSequence.compile("a = 1 + 2")
+ *     RubyVM::InstructionSequence.compile_prism("a = 1 + 2")
  *     #=> <RubyVM::InstructionSequence:<compiled>@<compiled>>
  *
  *     path = "test.rb"
- *     RubyVM::InstructionSequence.compile(File.read(path), path, File.expand_path(path))
+ *     RubyVM::InstructionSequence.compile_prism(File.read(path), path, File.expand_path(path))
  *     #=> <RubyVM::InstructionSequence:<compiled>@test.rb:1>
  *
  *     file = File.open("test.rb")
- *     RubyVM::InstructionSequence.compile(file)
+ *     RubyVM::InstructionSequence.compile_prism(file)
  *     #=> <RubyVM::InstructionSequence:<compiled>@<compiled>:1>
  *
  *     path = File.expand_path("test.rb")
- *     RubyVM::InstructionSequence.compile(File.read(path), path, path)
+ *     RubyVM::InstructionSequence.compile_prism(File.read(path), path, path)
  *     #=> <RubyVM::InstructionSequence:<compiled>@/absolute/path/to/test.rb:1>
  *
  */
@@ -4283,6 +4325,7 @@ Init_ISeq(void)
     (void)iseq_s_load;
 
     rb_define_singleton_method(rb_cISeq, "compile", iseqw_s_compile, -1);
+    rb_define_singleton_method(rb_cISeq, "compile_parsey", iseqw_s_compile_parsey, -1);
     rb_define_singleton_method(rb_cISeq, "compile_prism", iseqw_s_compile_prism, -1);
     rb_define_singleton_method(rb_cISeq, "compile_file_prism", iseqw_s_compile_file_prism, -1);
     rb_define_singleton_method(rb_cISeq, "new", iseqw_s_compile, -1);
diff --git a/prism_compile.c b/prism_compile.c
index a9c8aea4b4..5f5e0aa6fe 100644
--- a/prism_compile.c
+++ b/prism_compile.c
@@ -6797,6 +6797,8 @@ pm_compile_array_node(rb_iseq_t *iseq, const pm_node_t *node, const pm_node_list
                 // Create the temporary array.
                 for (; tmp_array_size; tmp_array_size--)
                     rb_ary_push(tmp_array, pm_static_literal_value(iseq, elements->nodes[index++], scope_node));
+
+                index--; // about to be incremented by for loop
                 OBJ_FREEZE(tmp_array);
 
                 // Emit the optimized code.
diff --git a/test/ruby/test_compile_prism.rb b/test/ruby/test_compile_prism.rb
index afe39f9aef..92c1304e9b 100644
--- a/test/ruby/test_compile_prism.rb
+++ b/test/ruby/test_compile_prism.rb
@@ -768,6 +768,9 @@ module Prism
       assert_prism_eval("a = [1,2]; [0, *a, 3, 4, *5..6, 7, 8, *9..11]")
       assert_prism_eval("[[*1..2], 3, *4..5]")
 
+      elements = Array.new(64) { ":foo" }
+      assert_prism_eval("[#{elements.join(", ")}, bar: 1, baz: 2]")
+
       # Test keyword splat inside of array
       assert_prism_eval("[**{x: 'hello'}]")
 
@@ -2628,7 +2631,7 @@ end
     def compare_eval(source, raw:, location:)
       source = raw ? source : "class Prism::TestCompilePrism\n#{source}\nend"
 
-      ruby_eval = RubyVM::InstructionSequence.compile(source).eval
+      ruby_eval = RubyVM::InstructionSequence.compile_parsey(source).eval
       prism_eval = RubyVM::InstructionSequence.compile_prism(source).eval
 
       if ruby_eval.is_a? Proc