Reject END { break } for Ruby 3.5

For [Bug #20409]

Author: Earlopain

snapshots/3.3-3.4/end_block_exit.txt

@@ -0,0 +1,33 @@
+@ ProgramNode (location: (1,0)-(7,1))
+├── flags: ∅
+├── locals: []
+└── statements:
+    @ StatementsNode (location: (1,0)-(7,1))
+    ├── flags: ∅
+    └── body: (length: 2)
+        ├── @ PostExecutionNode (location: (1,0)-(3,1))
+        │   ├── flags: newline
+        │   ├── statements:
+        │   │   @ StatementsNode (location: (2,2)-(2,8))
+        │   │   ├── flags: ∅
+        │   │   └── body: (length: 1)
+        │   │       └── @ ReturnNode (location: (2,2)-(2,8))
+        │   │           ├── flags: newline
+        │   │           ├── keyword_loc: (2,2)-(2,8) = "return"
+        │   │           └── arguments: ∅
+        │   ├── keyword_loc: (1,0)-(1,3) = "END"
+        │   ├── opening_loc: (1,4)-(1,5) = "{"
+        │   └── closing_loc: (3,0)-(3,1) = "}"
+        └── @ PostExecutionNode (location: (5,0)-(7,1))
+            ├── flags: newline
+            ├── statements:
+            │   @ StatementsNode (location: (6,2)-(6,7))
+            │   ├── flags: ∅
+            │   └── body: (length: 1)
+            │       └── @ BreakNode (location: (6,2)-(6,7))
+            │           ├── flags: newline
+            │           ├── arguments: ∅
+            │           └── keyword_loc: (6,2)-(6,7) = "break"
+            ├── keyword_loc: (5,0)-(5,3) = "END"
+            ├── opening_loc: (5,4)-(5,5) = "{"
+            └── closing_loc: (7,0)-(7,1) = "}"

snapshots/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)-(2,6))
+            │   ├── flags: ∅
+            │   └── body: (length: 1)
+            │       └── @ NextNode (location: (2,2)-(2,6))
+            │           ├── flags: newline
+            │           ├── arguments: ∅
+            │           └── keyword_loc: (2,2)-(2,6) = "next"
+            ├── keyword_loc: (1,0)-(1,3) = "END"
+            ├── opening_loc: (1,4)-(1,5) = "{"
+            └── closing_loc: (3,0)-(3,1) = "}"

src/prism.c

@@ -14950,12 +14950,22 @@ 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
                 // in these contexts.
                 return;
+            case PM_CONTEXT_POSTEXE:
+                // https://bugs.ruby-lang.org/issues/20409
+                if (context_node->context == PM_CONTEXT_POSTEXE) {
+                    if (parser->version < PM_OPTIONS_VERSION_CRUBY_4_0) {
+                        return;
+                    }
+                    if (PM_NODE_TYPE_P(node, PM_NEXT_NODE)) {
+                        return;
+                    }
+                }
+            PRISM_FALLTHROUGH
             case PM_CONTEXT_DEF:
             case PM_CONTEXT_DEF_PARAMS:
             case PM_CONTEXT_DEF_ELSE:

test/prism/errors/4.0/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}/4.0/end_block_exit.txt"
+    ]
+
     filepaths.each do |filepath|
       ruby_versions_for(filepath).each do |version|
         define_method(:"test_#{version}_#{File.basename(filepath, ".txt")}") do
@@ -88,7 +93,9 @@ 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 +1,7 @@
+END {
+  return
+}
+
+END {
+  break
+}

test/prism/fixtures/end_block_exit.txt

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