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yacc: fix push parser

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When a pstate is used for multiple successive parses, some state may
leak from one run into the following one.  That was introduced in
330552ea49 "yacc.c: push: don't clear
the parser state when accepting/rejecting".

Reported by Ryan <dev@splintermail.com>
https://lists.gnu.org/r/bug-bison/2021-03/msg00000.html

* data/skeletons/yacc.c (yypush_parse): We reusing a pstate from a
previous run, do behave as if it were the first run.
* tests/push.at (Pstate reuse): Check this.
This commit is contained in:
Akim Demaille
2021-03-07 10:01:53 +01:00
parent a774839ca8
commit cf899f7a7c
3 changed files with 139 additions and 8 deletions
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127
tests/push.at
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@@ -25,7 +25,7 @@ AT_BANNER([[Push Parsing Tests]])
AT_SETUP([[Memory Leak for Early Deletion]])
# Requires Valgrind.
AT_BISON_OPTION_PUSHDEFS
AT_BISON_OPTION_PUSHDEFS([%define api.push-pull push])
AT_DATA_GRAMMAR([[input.y]],
[[
%{
@@ -144,7 +144,7 @@ AT_CLEANUP
AT_SETUP([[Unsupported Skeletons]])
AT_BISON_OPTION_PUSHDEFS
AT_BISON_OPTION_PUSHDEFS([%define api.push-pull push])
AT_DATA([[input.y]],
[[%glr-parser
%define api.push-pull push
@@ -158,3 +158,126 @@ AT_BISON_CHECK([[input.y]], [[1]], [],
]])
AT_CLEANUP
## -------------- ##
## Pstate reuse. ##
## -------------- ##
AT_SETUP([[Pstate reuse]])
# Make sure that when a single pstate is used for multiple successive
# parses, no state from a previous run leaks into the following one.
#
# See https://lists.gnu.org/r/bug-bison/2021-03/msg00000.html.
AT_BISON_OPTION_PUSHDEFS([%define api.push-pull push])
AT_DATA_GRAMMAR([[input.y]],
[[%code top {
#include <stdlib.h>
#include <string.h>
static char *string_concat (char *a, char *b);
]AT_YYERROR_DECLARE[
}
%define parse.trace
%define api.pure full
%define api.push-pull push
%expect 0
%union {
char *sval;
};
%destructor { free ($$); } <sval>
%printer { fprintf (yyo, "%s", $$); } <sval>
%token <sval> RAW
%token EOL
%type <sval> text
%%
line
: text EOL { printf ("text: %s\n", $1); free ($1); YYACCEPT; };
text
: RAW { $$ = $1; }
| text RAW { $$ = string_concat ($1, $2); }
;
%%
]AT_YYERROR_DEFINE[
static char *
string_concat (char *a, char *b)
{
size_t la = strlen (a);
size_t lb = strlen (b);
char *res = YY_CAST (char *, malloc (la + lb + 1));
strcpy (res, a);
strcpy (res + la, b);
free (a);
free (b);
return res;
}
static int
push (yypstate *ps, yytoken_kind_t kind, const char *str)
{
YYSTYPE lval;
lval.sval = str ? strdup (str) : YY_NULLPTR;
switch (yypush_parse (ps, kind, &lval))
{
case 0:
return 0;
case YYPUSH_MORE:
// parsing incomplete, but valid; parser not reset
return 0;
case 1:
// YYABORT or syntax invalid; parser is reset
fprintf (stderr, "invalid input, but no error was thrown\n");
return 1;
case 2:
// memory exhaustion; parser is reset
fprintf (stderr, "memory exhaustion during yypush_parse\n");
return 1;
}
return 1;
}
int
main (void)
{
yydebug = !!getenv ("YYDEBUG");
yypstate *ps = yypstate_new ();
#define PUSH(Kind, Val) \
do { \
if (push (ps, Kind, Val)) \
return 1; \
} while (0)
PUSH (RAW, "te");
PUSH (RAW, "xt");
PUSH (EOL, YY_NULLPTR);
PUSH (RAW, "te");
PUSH (RAW, "xt");
PUSH (EOL, YY_NULLPTR);
yypstate_delete (ps);
return 0;
}
]])
AT_FULL_COMPILE([input])
AT_CHECK([./input], 0,
[[text: text
text: text
]])
AT_BISON_OPTION_POPDEFS
AT_CLEANUP