add assertions about format lexing

[perl #132158] describes a situation in which a weird kind of unterminated
format caused the parser to crash.  Add some assertions that catch the
messed up parser state before it actually crashes.

diff --git a/toke.c b/toke.c
index afcd719..3154fc1 100644 (file)
--- a/toke.c
+++ b/toke.c
@@ -5074,6 +5074,7 @@ Perl_yylex(pTHX)
 
        return yylex();
     case LEX_FORMLINE:
+       assert(PL_lex_formbrack);
        s = scan_formline(PL_bufptr);
        if (!PL_lex_formbrack)
        {
@@ -6281,6 +6282,7 @@ Perl_yylex(pTHX)
        if (PL_lex_brackets && PL_lex_brackstack[PL_lex_brackets-1] == XFAKEEOF)
            TOKEN(0);
       rightbracket:
+       assert(s != PL_bufend);
        s++;
        if (PL_lex_brackets <= 0)
            /* diag_listed_as: Unmatched right %s bracket */
@@ -6311,7 +6313,7 @@ Perl_yylex(pTHX)
            return yylex();             /* ignore fake brackets */
        }
        force_next(formbrack ? '.' : '}');
-       if (formbrack) LEAVE;
+       if (formbrack) LEAVE_with_name("lex_format");
        if (formbrack == 2) { /* means . where arguments were expected */
            force_next(';');
            TOKEN(FORMRBRACK);
@@ -6457,7 +6459,7 @@ Perl_yylex(pTHX)
                t++;
            if (*t == '\n' || *t == '#') {
                formbrack = 1;
-               ENTER;
+               ENTER_with_name("lex_format");
                SAVEI8(PL_parser->form_lex_state);
                SAVEI32(PL_lex_formbrack);
                PL_parser->form_lex_state = PL_lex_state;