Re: [PATCH 1/3] Remove include xalloc.h from libpoke/pkl-env.c

[Tim Rühsen]

Hi Jose,

On 16.05.20 18:46, Jose E. Marchesi wrote:
> 
> Hi Tim.
> 
>     diff --git a/libpoke/pkl-tab.y b/libpoke/pkl-tab.y
>     index 23c1fd8a..9ef6519e 100644
>     --- a/libpoke/pkl-tab.y
>     +++ b/libpoke/pkl-tab.y
>     @@ -414,6 +414,8 @@ pushlevel:
>         %empty
>               {
>                        pkl_parser->env = pkl_env_push_frame (pkl_parser->env);
>     +                  if (!pkl_parser->env)
>     +                    YYERROR;
>                      }
>              ;
> 
> The yyparse function (in this case pkl_tab_parse) should return 2 in
> case of memory exhaustion:
> 
>  -- Function: int yyparse (void)
>      The value returned by ‘yyparse’ is 0 if parsing was successful
>      (return is due to end-of-input).
> 
>      The value is 1 if parsing failed because of invalid input, i.e.,
>      input that contains a syntax error or that causes ‘YYABORT’ to be
>      invoked.
> 
>      The value is 2 if parsing failed due to memory exhaustion.
> 
> Both YYERROR and YYABORT make yyparse to return 1.  The difference
> betweent the two is that YYABORT returns immediately, whereas YYERROR
> initiates syntax error recovery, executing rule destructors and the
> like.
> 
> I don't think we sould use YYERROR for out-of-memory conditions.
> First, because it makes yyparse to return 1, not 2.
> Second, because it is not a syntax error condition.
> 
> Looking at bison internals, this will probably work:
> 
>   goto yyexhaustedlab;

Yeah I saw that label and couldn't decide for a goto. My thought then
was "maybe YYERROR just does the right thing (what else is
yyexhaustedlab good for) - if not Jose will correct me :P".

> Then again, this relies on bison's internals, so it may be problematic.
> Maybe this is something to ask for in address@hidden?

Hard to believe that we are the first users who try to deal with a OOM
situation in a parser ;) Not much time now, but will ask there if no one
else here knows an answer.

Regards, Tim

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