Reject END { break } for Ruby 3.5

For [Bug #20409]

Author: Earlopain

snapshots/3.3-3.4/end_block_exit.txt

@@ -0,0 +1,20 @@
+@ ProgramNode (location: (1,0)-(3,1))
+├── flags: ∅
+├── locals: []
+└── statements:
+    @ StatementsNode (location: (1,0)-(3,1))
+    ├── flags: ∅
+    └── body: (length: 1)
+        └── @ PostExecutionNode (location: (1,0)-(3,1))
+            ├── flags: newline
+            ├── statements:
+            │   @ StatementsNode (location: (2,2)-(2,7))
+            │   ├── flags: ∅
+            │   └── body: (length: 1)
+            │       └── @ BreakNode (location: (2,2)-(2,7))
+            │           ├── flags: newline
+            │           ├── arguments: ∅
+            │           └── keyword_loc: (2,2)-(2,7) = "break"
+            ├── keyword_loc: (1,0)-(1,3) = "END"
+            ├── opening_loc: (1,4)-(1,5) = "{"
+            └── closing_loc: (3,0)-(3,1) = "}"

src/prism.c

@@ -15799,7 +15799,6 @@ parse_block_exit(pm_parser_t *parser, pm_node_t *node) {
             case PM_CONTEXT_LAMBDA_ENSURE:
             case PM_CONTEXT_LAMBDA_RESCUE:
             case PM_CONTEXT_LOOP_PREDICATE:
-            case PM_CONTEXT_POSTEXE:
             case PM_CONTEXT_UNTIL:
             case PM_CONTEXT_WHILE:
                 // These are the good cases. We're allowed to have a block exit
@@ -15812,10 +15811,16 @@ parse_block_exit(pm_parser_t *parser, pm_node_t *node) {
             case PM_CONTEXT_DEF_RESCUE:
             case PM_CONTEXT_MAIN:
             case PM_CONTEXT_PREEXE:
+            case PM_CONTEXT_POSTEXE:
             case PM_CONTEXT_SCLASS:
             case PM_CONTEXT_SCLASS_ELSE:
             case PM_CONTEXT_SCLASS_ENSURE:
             case PM_CONTEXT_SCLASS_RESCUE:
+                // https://bugs.ruby-lang.org/issues/20409
+                if (context_node->context == PM_CONTEXT_POSTEXE && parser->version < PM_OPTIONS_VERSION_CRUBY_3_5) {
+                    return;
+                }
+
                 // These are the bad cases. We're not allowed to have a block
                 // exit in these contexts.
                 //

test/prism/errors/3.5/end_block_exit.txt

@@ -0,0 +1,5 @@
+END {
+  break
+  ^~~~~ Invalid break
+}
+

test/prism/errors_test.rb

@@ -9,6 +9,11 @@ class ErrorsTest < TestCase
     base = File.expand_path("errors", __dir__)
     filepaths = Dir["**/*.txt", base: base]
 
+    PARSE_Y_EXCLUDES = [
+      # https://bugs.ruby-lang.org/issues/20409
+      "#{base}/3.5/end_block_exit.txt"
+    ]
+
     filepaths.each do |filepath|
       ruby_versions_for(filepath).each do |version|
         define_method(:"test_#{version}_#{File.basename(filepath, ".txt")}") do
@@ -70,7 +75,9 @@ def assert_errors(filepath, version)
       expected = File.read(filepath, binmode: true, external_encoding: Encoding::UTF_8)
 
       source = expected.lines.grep_v(/^\s*\^/).join.gsub(/\n*\z/, "")
-      refute_valid_syntax(source) if current_major_minor == version
+      if current_major_minor == version && !PARSE_Y_EXCLUDES.include?(filepath)
+        refute_valid_syntax(source)
+      end
 
       result = Prism.parse(source, version: version)
       errors = result.errors

test/prism/fixtures/3.3-3.4/end_block_exit.txt

@@ -0,0 +1,3 @@
+END {
+  break
+}