Re: no test coverage for ALTER FOREIGN DATA WRAPPER name HANDLER ...

On 2017/09/13 16:42, Ashutosh Bapat wrote:
> On Wed, Sep 13, 2017 at 7:49 AM, Amit Langote wrote:
>> In the attached updated patch, I created separate .source files in
>> src/test/regress/input and output directories called fdw_handler.source
>> and put the test_fdw_handler function definition there. When I had
>> originally thought of it back when I wrote the patch, it seemed to be an
>> overkill, because we're just normally defining a single C function there
>> to be used in the newly added foreign_data tests. In any case, we need to
>> go the .source file way, because that's the only way to refer to paths to
>> .so library when defining C language functions.
>
> It still looks like an overkill to add a new file to define a dummy
> FDW handler. Why do we need to define a handler as a C function? Can't
> we define handler as a SQL function. If we could do that we could add
> the function definition in foreign_data.sql itself.

I guess that's because the last time I tried to define the handler as a
SQL function, I couldn't:

create function test_fdw_handler() returns fdw_handler as '' language sql;
ERROR: SQL functions cannot return type fdw_handler

fdw_handler is a pseudo-type, which neither SQL nor plpgsql function can
return.

Am I missing something?

Thanks,
Amit