Re: More CppAsString2() in psql's describe.c - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: More CppAsString2() in psql's describe.c
Date
Msg-id a93de185-187c-443e-b621-fd7ceb028501@eisentraut.org
Whole thread Raw
Responses Re: More CppAsString2() in psql's describe.c
Re: More CppAsString2() in psql's describe.c
List pgsql-hackers
On 28.11.24 07:34, Michael Paquier wrote:
> -                          "WHERE p.prokind = 'a'\n",
> +                          "WHERE p.prokind = " CppAsString2(PROKIND_AGGREGATE) "\n",

I noticed something here.  If the symbol that is the argument of 
CppAsString2() is not defined, maybe because there is a typo or because 
the required header file is not included, then there is no compiler 
diagnostic.  Instead, the symbol is just used as is, which might then 
result in an SQL error or go unnoticed if there is no test coverage.

Now, the same is technically true for the previous code with the 
hardcoded character values, but I think at least something like

     "WHERE p.prokind = 'a'\n",

is easier to eyeball for correctness, whereas, you know, 
CppAsString2(PROPARALLEL_RESTRICTED), is quite something.

I think this would be more robust if it were written something like

     "WHERE p.prokind = '%c'\n", PROKIND_AGGREGATE

(Moreover, the current structure assumes that the C character literal 
syntax used by the PROKIND_* and other symbols happens to be the same as 
the SQL string literal syntax required in those queries, which is just 
an accident.)



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