Re: Clobbered parameter names via DECLARE in PL/PgSQL

On 04/15/2012 03:49 AM, Brendan Jurd wrote:
> Hello hackers,
>
> It turns out that in a PL/PgSQL function, you can DECLARE a variable
> using the same name as one of the function parameters.  This has the
> effect of clobbering the parameter, for example:
>
...
>
> I would suggest that if the user DECLAREs a variable with the same
> name as a parameter, it is very evidently a programming error, and we
> should raise the same "duplicate declaration" error.  I haven't yet
> looked at how difficult this would be to fix, but if there are no
> objections I would like to attempt a patch.

This doesn't need fixing, IMNSHO. The name isn't "clobbered" and the 
partameter is accessible.

The docs state:
   Any statement in the statement section of a block can be a subblock.   Subblocks can be used for logical grouping or
tolocalize variables   to a small group of statements. Variables declared in a subblock   mask any similarly-named
variablesof outer blocks for the duration   of the subblock; but you can access the outer variables anyway if   you
qualifytheir names with their block's label.   ...   There is actually a hidden "outer block" surrounding the body of
any  PL/pgSQL function. This block provides the declarations of the   function's parameters (if any), as well as some
specialvariables   such as FOUND (see Section 39.5.5). The outer block is labeled with   the function's name, meaning
thatparameters and special variables   can be qualified with the function's name.
 

Note that you can label the outermost block of the function body, as the 
example in the docs shows.

cheers

andrew