Re: Improve error handling in pltcl

On 3/3/16 8:51 AM, Pavel Stehule wrote:
> Hi
>
> I am testing behave, and some results looks strange

Thanks for the review!

> postgres=# \sf foo
> CREATE OR REPLACE FUNCTION public.foo()
>   RETURNS void
>   LANGUAGE plpgsql
> AS $function$
> begin
>    raise exception sqlstate 'ZZ666' using message='hello, world',
> detail='hello, my world', hint = 'dont afraid';
> end
> $function$
>
> postgres=# select tcl_eval('spi_exec "select foo();"');
> ERROR:  38000: hello, world
> CONTEXT:  hello, world   <<<<==========???????
>
> the message was in context. Probably it is out of scope of this patch,
> but it isn't consistent with other PL
>
>
>      while executing
> "spi_exec "select foo();""
>      ("eval" body line 1)
>      invoked from within
> "eval $1"
>      (procedure "__PLTcl_proc_16864" line 3)
>      invoked from within
> "__PLTcl_proc_16864 {spi_exec "select foo();"}"
> in PL/Tcl function "tcl_eval"
> LOCATION:  throw_tcl_error, pltcl.c:1217
> Time: 1.178 ms

Both problems actually exists in HEAD. The issue is this line in
throw_tcl_error:

    econtext = utf_u2e(Tcl_GetVar(interp, "errorInfo", TCL_GLOBAL_ONLY));

Offhand I don't see any great way to improve that behavior, and in any
case it seems out of scope for this patch. As a workaround I'm just
forcing psql error VERBOSITY to terse for now.

> postgres=# select tcl_eval('join $::errorCode "\n"');
>                  tcl_eval
> ═════════════════════════════════════════
>   POSTGRES                               ↵
>   message                                ↵
>   hello, world                           ↵
>   detail                                 ↵
>   hello, my world                        ↵
>   hint                                   ↵
>   dont afraid                            ↵
>   domain                                 ↵
>   plpgsql-9.6                            ↵
>   context_domain                         ↵
>   postgres-9.6                           ↵
>   context                                ↵
>   PL/pgSQL function foo() line 3 at RAISE↵
>   SQL statement "select foo();"          ↵
>   cursor_position                        ↵
>   0                                      ↵
>   filename                               ↵
>   pl_exec.c                              ↵
>   lineno                                 ↵
>   3165                                   ↵
>   funcname                               ↵
>   exec_stmt_raise
> (1 row)
>
> I miss a SQLSTATE.

Great catch. Fixed.

> Why is used List object instead dictionary? TCL supports it
> https://www.tcl.tk/man/tcl8.5/tutorial/Tcl23a.html

Because errorCode unfortunately is an array and not a dict. It doesn't
really seem worth messing with it in the eval since this is just a
sanity check...

New patch attached. It also removes some other unstable output from the
regression test.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com