deps: parser v0.13.1, so END { } runs instead of killing the process

README.md

@@ -676,7 +676,6 @@ Otherwise:
 | `pp` | neither `Kernel#pp` nor `require "pp"` exists (`require "prettyprint"` does work) |
 | `Process.fork` | does not exist — Go's runtime cannot be forked safely |
 | `Kernel#fork` | **exists, and does not fork.** `fork { ... }` runs the block **in the same process**, so the “child” mutates the parent's globals, `ENV` and working directory, and returns a synthetic pid (`100001`, counting up) while `Process.pid` is unchanged. Under MRI the block runs in a real child and the parent is untouched. A `SystemExit` raised inside the block unwinds the whole program |
-| `END { }` | **crashes the process** with a Go panic when the handler runs at exit — `panic: slice bounds out of range [:1] with capacity 0`, exit 2, where MRI runs the block. For an embedder it takes the host down rather than returning an error from `Run`. Tracked as #805. `BEGIN { }` works. Both used to be refused by the front end, which is how this row came to understate it: a gap turned into a crash and the note still described the gap |
 | `Thread#backtrace` for another thread | raises `NotImplementedError`; rbgo keeps one frame stack per VM, not per thread |
 
 ## Platforms

go.mod

@@ -129,7 +129,7 @@ require (
 	github.com/go-ruby-pagy/pagy v0.0.0-20260717071719-997d15eee011
 	github.com/go-ruby-paper-trail/paper-trail v0.0.0-20260717071745-42a249656e5a
 	github.com/go-ruby-parquet/parquet v0.0.0-20260923211642-bc75bcb9031e
-	github.com/go-ruby-parser/parser v0.13.0
+	github.com/go-ruby-parser/parser v0.13.1
 	github.com/go-ruby-pathname/pathname v0.0.0-20260916100446-0824484b665f
 	github.com/go-ruby-pg/pg v0.0.0-20260916100523-3831ec811a67
 	github.com/go-ruby-prawn/prawn v0.0.0-20260927145511-370d5985305c

go.sum

@@ -533,8 +533,8 @@ github.com/go-ruby-paper-trail/paper-trail v0.0.0-20260717071745-42a249656e5a h1
 github.com/go-ruby-paper-trail/paper-trail v0.0.0-20260717071745-42a249656e5a/go.mod h1:z370KNJcUH8n39yLdlT0Y1QvHukxjsq1XjGpIzvfqWE=
 github.com/go-ruby-parquet/parquet v0.0.0-20260923211642-bc75bcb9031e h1:pxhP3nIRxTpj99e74JAVpGj7JQtRSNqLb+B5x2WT5N4=
 github.com/go-ruby-parquet/parquet v0.0.0-20260923211642-bc75bcb9031e/go.mod h1:wC+J6qfQ8C0aKgi5qsbR03DYrLLuXXezUBHl967am/E=
-github.com/go-ruby-parser/parser v0.13.0 h1:JspoqXWvdv1J1LSknUZmCKWwO5x1xT+1CbhFfRaEtNA=
-github.com/go-ruby-parser/parser v0.13.0/go.mod h1:Se+ZvnD/4Vm0RRe1U5kZi0GmPSvSczJJXdZLiB0PlJY=
+github.com/go-ruby-parser/parser v0.13.1 h1:gq7QVT7KdRp7nZt1UHsa73YDo77qrD8kGdQY/GVEA6g=
+github.com/go-ruby-parser/parser v0.13.1/go.mod h1:Se+ZvnD/4Vm0RRe1U5kZi0GmPSvSczJJXdZLiB0PlJY=
 github.com/go-ruby-pathname/pathname v0.0.0-20260916100446-0824484b665f h1:9pt89wlAp12vbCNGFYmbSqp/PJTHRwUx1yNDXW5hWRI=
 github.com/go-ruby-pathname/pathname v0.0.0-20260916100446-0824484b665f/go.mod h1:IvW5q5Kyl5l3hrYwiHylOEmk5hpGSo7XqcmUXBHF5H0=
 github.com/go-ruby-pg/pg v0.0.0-20260916100523-3831ec811a67 h1:X9MKhEAV60oYoL94tqb11lfLw3yW097mVqfjDdy5PK0=

internal/vm/exe_block_test.go

@@ -0,0 +1,46 @@
+// Copyright (c) the go-embedded-ruby/ruby authors
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+package vm_test
+
+import "testing"
+
+// TestEndBlockRunsInsteadOfCrashing (#805).
+//
+// `END { }` used to end the process with an uncontained Go panic --
+// `slice bounds out of range [:1] with capacity 0`, exit 2 -- when the handler
+// ran at exit. For a program that is a crash instead of an answer; for an
+// embedder it is worse, because ruby.Run does not return an error, it takes the
+// host process down.
+//
+// The cause was in the parser and is fixed by v0.13.1: `END { }` desugars to
+// `at_exit { }`, and the Block it built left SplatIndex at Go's zero value --
+// which is a valid index, where the field's "no splat" value is -1. So the
+// block claimed a *splat parameter at position 0 with no parameters to hold it,
+// and this compiler's rest-binding read past an empty environment.
+//
+// The test lives HERE as well as upstream because the defect was invisible in
+// the AST: the parser's own suite was green throughout, and the whole cost
+// landed on the consumer that lowers a Block. A downgrade of the dependency
+// brings the crash back, and this is what notices.
+func TestEndBlockRunsInsteadOfCrashing(t *testing.T) {
+	checkCases(t, []runCase{
+		{`END { puts "E" }`, "E\n"},
+		// MRI runs END handlers after the program body, in reverse order of
+		// registration -- the ordering is the part a "did it crash" test misses.
+		{`puts "main"
+END { puts "E" }`, "main\nE\n"},
+		{`END { puts "first registered" }
+END { puts "second registered" }`, "second registered\nfirst registered\n"},
+		// BEGIN runs before the body and was never broken; it is here so a
+		// regression in either one is attributable to the right half.
+		{`BEGIN { puts "B" }
+puts "main"
+END { puts "E" }`, "B\nmain\nE\n"},
+		// at_exit is the shape END desugars to, and it also never broke: if this
+		// one ever fails with the others, the fault is in at_exit, not in END.
+		{`at_exit { puts "A" }
+puts "main"`, "main\nA\n"},
+	})
+}