merge revision(s) 1bc8838d60: [Backport #19750]

Handle unterminated unicode escapes in regexps

	This fixes an infinite loop possible after ec3542229b.
	For \u{} escapes in regexps, skip validation in the parser, and rely on the regexp
	code to handle validation. This is necessary so that invalid unicode escapes in
	comments in extended regexps are allowed.

	Fixes [Bug #19750]

	Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>
	---
	 parse.y                 | 97 ++++++++++++++++++++++++++++++++-----------------
	 test/ruby/test_parse.rb | 16 ++++++++
	 2 files changed, 79 insertions(+), 34 deletions(-)

parse.y

@@ -7260,6 +7260,8 @@ tokadd_codepoint(struct parser_params *p, rb_encoding **encp,
     return TRUE;
 }
 
+static int tokadd_mbchar(struct parser_params *p, int c);
+
 /* return value is for ?\u3042 */
 static void
 tokadd_utf8(struct parser_params *p, rb_encoding **encp,
@@ -7277,6 +7279,32 @@ tokadd_utf8(struct parser_params *p, rb_encoding **encp,
     if (regexp_literal) { tokadd(p, '\\'); tokadd(p, 'u'); }
 
     if (peek(p, open_brace)) {  /* handle \u{...} form */
+        if (regexp_literal && p->lex.strterm->u.literal.u1.func == str_regexp) {
+            /*
+             * Skip parsing validation code and copy bytes as-is until term or
+             * closing brace, in order to correctly handle extended regexps where
+             * invalid unicode escapes are allowed in comments. The regexp parser
+             * does its own validation and will catch any issues.
+             */
+            int c = *p->lex.pcur;
+            tokadd(p, c);
+            for (c = *++p->lex.pcur; p->lex.pcur < p->lex.pend; c = *++p->lex.pcur) {
+                if (c == close_brace) {
+                    tokadd(p, c);
+                    ++p->lex.pcur;
+                    break;
+                }
+                else if (c == term) {
+                    break;
+                }
+                if (c == '\\' && p->lex.pcur + 1 < p->lex.pend) {
+                    tokadd(p, c);
+                    c = *++p->lex.pcur;
+                }
+                tokadd_mbchar(p, c);
+            }
+        }
+        else {
             const char *second = NULL;
             int c, last = nextc(p);
             if (p->lex.pcur >= p->lex.pend) goto unterminated;
@@ -7316,6 +7344,7 @@ tokadd_utf8(struct parser_params *p, rb_encoding **encp,
             if (regexp_literal) tokadd(p, close_brace);
             nextc(p);
         }
+    }
     else {			/* handle \uxxxx form */
 	if (!tokadd_codepoint(p, encp, regexp_literal, FALSE)) {
 	    token_flush(p);

test/ruby/test_parse.rb

@@ -1041,6 +1041,22 @@ x = __ENCODING__
     assert_syntax_error("    0b\n", /\^/)
   end
 
+  def test_unclosed_unicode_escape_at_eol_bug_19750
+    assert_separately([], "#{<<-"begin;"}\n#{<<~'end;'}")
+    begin;
+      assert_syntax_error("/\\u", /too short escape sequence/)
+      assert_syntax_error("/\\u{", /unterminated regexp meets end of file/)
+      assert_syntax_error("/\\u{\\n", /invalid Unicode list/)
+      assert_syntax_error("/a#\\u{\\n/", /invalid Unicode list/)
+      re = eval("/a#\\u{\n$/x")
+      assert_match(re, 'a')
+      assert_not_match(re, 'a#')
+      re = eval("/a#\\u\n$/x")
+      assert_match(re, 'a')
+      assert_not_match(re, 'a#')
+    end;
+  end
+
   def test_error_def_in_argument
     assert_separately([], "#{<<-"begin;"}\n#{<<~"end;"}")
     begin;

version.h

@@ -11,7 +11,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 2
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 92
+#define RUBY_PATCHLEVEL 93
 
 #include "ruby/version.h"
 #include "ruby/internal/abi.h"