(perl #125351) abort parsing if parse errors happen in a sub lex

We've had a few reports of segmentation faults and other misbehaviour
when sub-parsing, such as within interpolated expressions, fails.

This change aborts compilation if anything complex enough to not be
parsed by the lexer is compiled in a sub-parse *and* an error
occurs within the sub-parse.

An earlier version of this patch failed on simpler expressions,
which caused many test failures, which this version doesn't (which may
just mean we need more tests...)

1 files changed, 2 insertions, 0 deletions

diff --git a/parser.h b/parser.h
index 4187e0a93d..216e9deca8 100644
--- a/parser.h
+++ b/parser.h
@@ -58,6 +58,7 @@ typedef struct yy_parser {
 				   1 = @{...}  2 = ->@ */
     U8		expect;		/* how to interpret ambiguous tokens */
     bool	preambled;
+    bool        sub_no_recover; /* can't recover from a sublex error */
     I32		lex_formbrack;	/* bracket count at outer format level */
     OP		*lex_inpat;	/* in pattern $) and $| are special */
     OP		*lex_op;	/* extra info to pass back on op */
@@ -95,6 +96,7 @@ typedef struct yy_parser {
     U16		in_my;		/* we're compiling a "my"/"our" declaration */
     U8		lex_state;	/* next token is determined */
     U8		error_count;	/* how many compile errors so far, max 10 */
+    U8		sub_error_count; /* the number of errors before sublexing */
     HV		*in_my_stash;	/* declared class of this "my" declaration */
     PerlIO	*rsfp;		/* current source file pointer */
     AV		*rsfp_filters;	/* holds chain of active source filters */