pp_ctl.c - use try_yyparse() for eval

CATCH_GET is never true in this code, so we never called try_yyparse()
which in turn meant we leaked debug data from failed evals. With this
in place an eval that dies during compile will always be handled by
doeval_comp() properly.

This includes changes to t/comp/readlines.t so it tests code that
croaks during compile, which used to leak and fail test but was not
actually tested.

This fixes GH Issue #20161.

Author: demerphq

pp_ctl.c

@@ -3686,12 +3686,13 @@ S_doeval_compile(pTHX_ U8 gimme, CV* outside, U32 seq, HV *hh)
 
     CALL_BLOCK_HOOKS(bhk_eval, saveop);
 
-    /* note that yyparse() may raise an exception, e.g. C<BEGIN{die}>,
-     * so honour CATCH_GET and trap it here if necessary */
-
-
+    /* we should never be CATCH_GET true here, as our immediate callers should
+     * always handle that case. */
+    assert(!CATCH_GET);
     /* compile the code */
-    yystatus = (!in_require && CATCH_GET) ? S_try_yyparse(aTHX_ GRAMPROG) : yyparse(GRAMPROG);
+    yystatus = (!in_require)
+               ? S_try_yyparse(aTHX_ GRAMPROG)
+               : yyparse(GRAMPROG);
 
     if (yystatus || PL_parser->error_count || !PL_eval_root) {
         PERL_CONTEXT *cx;
@@ -4578,6 +4579,8 @@ PP(pp_entereval)
     if (CATCH_GET)
         return docatch(Perl_pp_entereval);
 
+    assert(!CATCH_GET);
+
     gimme = GIMME_V;
     was = PL_breakable_sub_gen;
     saved_delete = FALSE;

t/comp/retainedlines.t

@@ -6,7 +6,7 @@
 # we've not yet verified that use works.
 # use strict;
 
-print "1..75\n";
+print "1..98\n";
 my $test = 0;
 
 sub failed {
@@ -101,7 +101,10 @@ for my $sep (' ', "\0") {
   my $prog = "sub $name {
     'This is $name'
   }
-1 +
+# 10 errors to triger a croak during compilation.
+1 +; 1 +; 1 +; 1 +; 1 +;
+1 +; 1 +; 1 +; 1 +; 1 +;
+1 +; # and one more for good measure.
 ";
 
   eval $prog and die;
@@ -119,7 +122,9 @@ foreach my $flags (0x0, 0x800, 0x1000, 0x1800) {
     # This is easier if we accept that the guts eval will add a trailing \n
     # for us
     my $prog = "1 + 1 + 1\n";
-    my $fail = "1 + \n";
+    my $fail = "1 +;\n" x 11; # we need 10 errors to trigger a croak during
+                              # compile, we add an extra one just for good
+                              # measure.
 
     is (eval $prog, 3, 'String eval works');
     if ($flags & 0x800) {