Thread: Some dead code in metaphone() of fuzzystrmatch.c

Some dead code in metaphone() of fuzzystrmatch.c

From

Michael Paquier

Date:

02 February 2015, 04:39:36

Hi all,

In metaphone() we do the following:
        /* return an empty string if we receive one */
        if (!(str_i_len > 0))
                PG_RETURN_TEXT_P(cstring_to_text(""));

        if (str_i_len > MAX_METAPHONE_STRLEN)
                ereport(ERROR,
                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                 errmsg("argument exceeds the maximum
length of %d bytes",
                                                MAX_METAPHONE_STRLEN)));

        if (!(str_i_len > 0))
                ereport(ERROR,
                                (errcode(ERRCODE_ZERO_LENGTH_CHARACTER_STRING),
                                 errmsg("argument is empty string")));
As we already return an empty string if the first condition is
satisfied, the third condition will never be satisfied. Returning an
empty string when output string is NULL has been introduced in commit
13629df of 2004, so I think that we should simply remove the code
block that will never be crossed, as in the patch attached.
Coverity has pointed out this issue.
Regards,
--
Michael

Attachment

20150202_metaphone_deadblock.patch

Re: Some dead code in metaphone() of fuzzystrmatch.c

From

Heikki Linnakangas

Date:

03 February 2015, 10:45:33

On 02/02/2015 03:39 AM, Michael Paquier wrote:
> In metaphone() we do the following:
>          /* return an empty string if we receive one */
>          if (!(str_i_len > 0))
>                  PG_RETURN_TEXT_P(cstring_to_text(""));
>
>          if (str_i_len > MAX_METAPHONE_STRLEN)
>                  ereport(ERROR,
>                                  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
>                                   errmsg("argument exceeds the maximum
> length of %d bytes",
>                                                  MAX_METAPHONE_STRLEN)));
>
>          if (!(str_i_len > 0))
>                  ereport(ERROR,
>                                  (errcode(ERRCODE_ZERO_LENGTH_CHARACTER_STRING),
>                                   errmsg("argument is empty string")));
> As we already return an empty string if the first condition is
> satisfied, the third condition will never be satisfied. Returning an
> empty string when output string is NULL has been introduced in commit
> 13629df of 2004, so I think that we should simply remove the code
> block that will never be crossed, as in the patch attached.

Applied, thanks.

- Heikki