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

On Wed, Sep 13, 2017 at 1:27 PM, Amit Langote
<Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> 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?

Ok. May be then create_function_1.sql is the right place. Just add it
to the section of passing tests and annotate that it's testing
creating an FDW handler. Sorry for jumping back and forth.

--
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company