Re: pgsql-server/src/backend commands/typecmds.c e ... - Mailing list pgsql-committers

Tom Lane writes:

> I looked over this change, and right offhand I don't agree with any of
> it.  None of the errors are "syntax" errors (if they were, gram.y would
> have barfed) and the textual error message changes generally seem to be
> trending in a less not more helpful direction.  What is your rationale
> for this, please?

A syntax error is a violation of the syntax rules of the SQL standard or a
hypothetical document describing the PostgreSQL feature set using the same
layout.  Syntax rules can be evaluated without knowing the state of the
database.  Not all syntax errors can be caught in gram.y; see below.

The way I see this is that "feature not supported" appeared to have been
used as a catch-all thinking "maybe someday this will work".  But it's
easy to see that this definition has no upper bound.  There are certain
things that we have a pretty clear idea about how it will work, and there
are a few stubs already in place, and we make a bit of a promise that
someday it will appear in the shape that is apparent today.

In detail:

> diff -cr ../cvs-pgsql/src/backend/commands/typecmds.c ./src/backend/commands/typecmds.c
> *** ../cvs-pgsql/src/backend/commands/typecmds.c    Tue Aug 19 22:59:37 2003
> --- ./src/backend/commands/typecmds.c    Wed Sep 10 00:42:55 2003
> ***************
> *** 594,601 ****
>           /* Check for unsupported constraint types */
>           if (IsA(newConstraint, FkConstraint))
>               ereport(ERROR,
> !                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !             errmsg("FOREIGN KEY constraints not supported for domains")));
>
>           /* otherwise it should be a plain Constraint */
>           if (!IsA(newConstraint, Constraint))
> --- 594,601 ----
>           /* Check for unsupported constraint types */
>           if (IsA(newConstraint, FkConstraint))
>               ereport(ERROR,
> !                     (errcode(ERRCODE_SYNTAX_ERROR),
> !             errmsg("foreign key constraints not possible for domains")));
>
>           /* otherwise it should be a plain Constraint */
>           if (!IsA(newConstraint, Constraint))

Foreign keys on domains aren't a feature that is a reasonable prospect.
The only reason this is caught here is that someone was lazy in gram.y
splitting up the contraint rules for tables and domains properly.

> ***************
> *** 672,685 ****
>                    */
>               case CONSTR_UNIQUE:
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                 errmsg("UNIQUE constraints not supported for domains")));
>                   break;
>
>               case CONSTR_PRIMARY:
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                          errmsg("PRIMARY KEY constraints not supported for domains")));
>                   break;
>
>               case CONSTR_ATTR_DEFERRABLE:
> --- 672,685 ----
>                    */
>               case CONSTR_UNIQUE:
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_SYNTAX_ERROR),
> !                 errmsg("unique constraints not possible for domains")));
>                   break;
>
>               case CONSTR_PRIMARY:
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_SYNTAX_ERROR),
> !                          errmsg("primary key constraints not possible for domains")));
>                   break;
>
>               case CONSTR_ATTR_DEFERRABLE:

The reason I lowercased these things is because in English you don't write
things in uppercase as a rule. -- But they are key words! -- Well, in
other places it was yelling "FOREIGN KEY constraints are not supported",
but maybe the user was writing it as a column constraint, so FOREIGN KEY
appears nowhere.  And what are the uppercase things telling the
translator?

> ***************
> *** 688,694 ****
>               case CONSTR_ATTR_IMMEDIATE:
>                   ereport(ERROR,
>                           (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                          errmsg("deferrability constraints not supported for domains")));
>                   break;
>
>               default:
> --- 688,694 ----
>               case CONSTR_ATTR_IMMEDIATE:
>                   ereport(ERROR,
>                           (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                          errmsg("specifying constraint deferrability not supported for domains")));
>                   break;
>
>               default:

That was clearly a miswording.

> ***************
> *** 1453,1460 ****
>       /* Check for unsupported constraint types */
>       if (IsA(newConstraint, FkConstraint))
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !            errmsg("FOREIGN KEY constraints not supported for domains")));
>
>       /* otherwise it should be a plain Constraint */
>       if (!IsA(newConstraint, Constraint))
> --- 1453,1460 ----
>       /* Check for unsupported constraint types */
>       if (IsA(newConstraint, FkConstraint))
>           ereport(ERROR,
> !                 (errcode(ERRCODE_SYNTAX_ERROR),
> !            errmsg("foreign key constraints not possible for domains")));
>
>       /* otherwise it should be a plain Constraint */
>       if (!IsA(newConstraint, Constraint))

See above.

> ***************
> *** 1465,1497 ****
>
>       switch (constr->contype)
>       {
> -         case CONSTR_DEFAULT:
> -             ereport(ERROR,
> -                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> -                      errmsg("use ALTER DOMAIN .. SET DEFAULT instead")));
> -             break;
> -
> -         case CONSTR_NOTNULL:
> -         case CONSTR_NULL:
> -             ereport(ERROR,
> -                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> -                      errmsg("use ALTER DOMAIN .. [ SET | DROP ] NOT NULL instead")));
> -             break;
> -
>           case CONSTR_CHECK:
>               /* processed below */
>               break;
>
>           case CONSTR_UNIQUE:
>               ereport(ERROR,
> !                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                 errmsg("UNIQUE constraints not supported for domains")));
>               break;
>
>           case CONSTR_PRIMARY:
>               ereport(ERROR,
> !                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !             errmsg("PRIMARY KEY constraints not supported for domains")));
>               break;
>
>           case CONSTR_ATTR_DEFERRABLE:
> --- 1465,1484 ----
>
>       switch (constr->contype)
>       {
>           case CONSTR_CHECK:
>               /* processed below */
>               break;
>
>           case CONSTR_UNIQUE:
>               ereport(ERROR,
> !                     (errcode(ERRCODE_SYNTAX_ERROR),
> !                      errmsg("unique constraints not possible for domains")));
>               break;
>
>           case CONSTR_PRIMARY:
>               ereport(ERROR,
> !                     (errcode(ERRCODE_SYNTAX_ERROR),
> !                      errmsg("primary key constraints not possible for domains")));
>               break;
>
>           case CONSTR_ATTR_DEFERRABLE:

The things I deleted at the top are not possible because gram.y won't
construct such things.  There's an internal-error catch-all at the bottom.

> ***************
> *** 1500,1506 ****
>           case CONSTR_ATTR_IMMEDIATE:
>               ereport(ERROR,
>                       (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                      errmsg("deferrability constraints not supported for domains")));
>               break;
>
>           default:
> --- 1487,1493 ----
>           case CONSTR_ATTR_IMMEDIATE:
>               ereport(ERROR,
>                       (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                      errmsg("specifying constraint deferrability not supported for domains")));
>               break;
>
>           default:

See above.

> diff -cr ../cvs-pgsql/src/backend/executor/execQual.c ./src/backend/executor/execQual.c
> *** ../cvs-pgsql/src/backend/executor/execQual.c    Tue Aug 19 22:59:40 2003
> --- ./src/backend/executor/execQual.c    Wed Sep 10 00:24:07 2003
> ***************
> *** 713,719 ****
>                   *isDone = ExprEndResult;
>               else
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                            errmsg("set-valued function called in context that cannot accept a set")));
>               return (Datum) 0;
>           }
> --- 713,719 ----
>                   *isDone = ExprEndResult;
>               else
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_SYNTAX_ERROR),
>                            errmsg("set-valued function called in context that cannot accept a set")));
>               return (Datum) 0;
>           }

This seems kind of obvious.  How would a "supported feature" that allows
set-valued functions to be called in contexts that cannot accept a set
look like.  By this standard, everything is an unsupported feature.

> ***************
> *** 757,763 ****
>            */
>           if (isDone == NULL)
>               ereport(ERROR,
> !                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                        errmsg("set-valued function called in context that cannot accept a set")));
>
>           /*
> --- 757,763 ----
>            */
>           if (isDone == NULL)
>               ereport(ERROR,
> !                     (errcode(ERRCODE_SYNTAX_ERROR),
>                        errmsg("set-valued function called in context that cannot accept a set")));
>
>           /*
> ***************
> *** 944,950 ****
>           /* We don't allow sets in the arguments of the table function */
>           if (argDone != ExprSingleResult)
>               ereport(ERROR,
> !                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                        errmsg("set-valued function called in context that cannot accept a set")));
>
>           /*
> --- 944,950 ----
>           /* We don't allow sets in the arguments of the table function */
>           if (argDone != ExprSingleResult)
>               ereport(ERROR,
> !                     (errcode(ERRCODE_SYNTAX_ERROR),
>                        errmsg("set-valued function called in context that cannot accept a set")));
>
>           /*
> ***************
> *** 2955,2961 ****
>               /* We have a set-valued expression in the tlist */
>               if (isDone == NULL)
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                            errmsg("set-valued function called in context that cannot accept a set")));
>               if (itemIsDone[resind] == ExprMultipleResult)
>               {
> --- 2955,2961 ----
>               /* We have a set-valued expression in the tlist */
>               if (isDone == NULL)
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_SYNTAX_ERROR),
>                            errmsg("set-valued function called in context that cannot accept a set")));
>               if (itemIsDone[resind] == ExprMultipleResult)
>               {
> diff -cr ../cvs-pgsql/src/backend/executor/functions.c ./src/backend/executor/functions.c
> *** ../cvs-pgsql/src/backend/executor/functions.c    Tue Aug 19 22:59:40 2003
> --- ./src/backend/executor/functions.c    Wed Sep 10 00:24:58 2003
> ***************
> *** 574,580 ****
>                   rsi->isDone = ExprEndResult;
>               else
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                            errmsg("set-valued function called in context that cannot accept a set")));
>               fcinfo->isnull = true;
>               result = (Datum) 0;
> --- 574,580 ----
>                   rsi->isDone = ExprEndResult;
>               else
>                   ereport(ERROR,
> !                         (errcode(ERRCODE_SYNTAX_ERROR),
>                            errmsg("set-valued function called in context that cannot accept a set")));
>               fcinfo->isnull = true;
>               result = (Datum) 0;
> ***************
> *** 613,619 ****
>               rsi->isDone = ExprMultipleResult;
>           else
>               ereport(ERROR,
> !                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                        errmsg("set-valued function called in context that cannot accept a set")));
>
>           /*
> --- 613,619 ----
>               rsi->isDone = ExprMultipleResult;
>           else
>               ereport(ERROR,
> !                     (errcode(ERRCODE_SYNTAX_ERROR),
>                        errmsg("set-valued function called in context that cannot accept a set")));
>
>           /*

See above.

> diff -cr ../cvs-pgsql/src/backend/parser/gram.y ./src/backend/parser/gram.y
> *** ../cvs-pgsql/src/backend/parser/gram.y    Sat Sep  6 16:01:51 2003
> --- ./src/backend/parser/gram.y    Wed Sep 10 00:25:54 2003
> ***************
> *** 4610,4616 ****
>                   {
>                       /* Disabled because it was too confusing, bjm 2002-02-18 */
>                       ereport(ERROR,
> !                             (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                                errmsg("LIMIT #,# syntax is not supported"),
>                                errhint("Use separate LIMIT and OFFSET clauses.")));
>                   }
> --- 4610,4616 ----
>                   {
>                       /* Disabled because it was too confusing, bjm 2002-02-18 */
>                       ereport(ERROR,
> !                             (errcode(ERRCODE_SYNTAX_ERROR),
>                                errmsg("LIMIT #,# syntax is not supported"),
>                                errhint("Use separate LIMIT and OFFSET clauses.")));
>                   }

It's syntax, and it's an error.  We cannot upgrade every syntax that we
deprecate to an unsupported feature.  If we removed that warning and let
the grammar itself handle it, it would become a syntax error anyway.

> diff -cr ../cvs-pgsql/src/backend/tcop/utility.c ./src/backend/tcop/utility.c
> *** ../cvs-pgsql/src/backend/tcop/utility.c    Tue Aug 19 23:00:08 2003
> --- ./src/backend/tcop/utility.c    Wed Sep 10 00:39:48 2003
> ***************
> *** 630,636 ****
>                    */
>                   switch (stmt->subtype)
>                   {
> !                     case 'T':    /* ALTER COLUMN DEFAULT */
>
>                           /*
>                            * Recursively alter column default for table and,
> --- 630,636 ----
>                    */
>                   switch (stmt->subtype)
>                   {
> !                     case 'T':    /* ALTER DOMAIN DEFAULT */
>
>                           /*
>                            * Recursively alter column default for table and,
> ***************
> *** 639,649 ****
>                           AlterDomainDefault(stmt->typename,
>                                              stmt->def);
>                           break;
> !                     case 'N':    /* ALTER COLUMN DROP NOT NULL */
>                           AlterDomainNotNull(stmt->typename,
>                                              false);
>                           break;
> !                     case 'O':    /* ALTER COLUMN SET NOT NULL */
>                           AlterDomainNotNull(stmt->typename,
>                                              true);
>                           break;
> --- 639,649 ----
>                           AlterDomainDefault(stmt->typename,
>                                              stmt->def);
>                           break;
> !                     case 'N':    /* ALTER DOMAIN DROP NOT NULL */
>                           AlterDomainNotNull(stmt->typename,
>                                              false);
>                           break;
> !                     case 'O':    /* ALTER DOMAIN SET NOT NULL */
>                           AlterDomainNotNull(stmt->typename,
>                                              true);
>                           break;

copy and paste laziness...

> diff -cr ../cvs-pgsql/src/backend/utils/adt/acl.c ./src/backend/utils/adt/acl.c
> *** ../cvs-pgsql/src/backend/utils/adt/acl.c    Tue Aug 19 23:00:09 2003
> --- ./src/backend/utils/adt/acl.c    Wed Sep 10 00:18:48 2003
> ***************
> *** 846,852 ****
>       else if (u_grantee != 0 && g_grantee != 0)
>       {
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                    errmsg("cannot specify both user and group")));
>       }
>       else if (u_grantee != 0)
> --- 846,852 ----
>       else if (u_grantee != 0 && g_grantee != 0)
>       {
>           ereport(ERROR,
> !                 (errcode(ERRCODE_SYNTAX_ERROR),
>                    errmsg("cannot specify both user and group")));
>       }
>       else if (u_grantee != 0)

This was never a feature, it was a definitional impossibility.

> diff -cr ../cvs-pgsql/src/backend/utils/adt/array_userfuncs.c ./src/backend/utils/adt/array_userfuncs.c
> *** ../cvs-pgsql/src/backend/utils/adt/array_userfuncs.c    Tue Aug 19 23:00:09 2003
> --- ./src/backend/utils/adt/array_userfuncs.c    Wed Sep 10 00:19:22 2003
> ***************
> *** 95,102 ****
>           indx = 1;
>       else
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                  errmsg("input must be empty or one-dimensional array")));
>
>       /*
>        * We arrange to look up info about element type only once per series
> --- 95,102 ----
>           indx = 1;
>       else
>           ereport(ERROR,
> !                 (errcode(ERRCODE_SYNTAX_ERROR),
> !                  errmsg("argument must be empty or one-dimensional array")));
>
>       /*
>        * We arrange to look up info about element type only once per series

Push works on a stack, and a stack is always one-dimensional.  It's never
going to be supported under the label "push".  Maybe a separate error
along the lines of "cardinality error" would be appropriate.

> diff -cr ../cvs-pgsql/src/backend/utils/adt/pgstatfuncs.c ./src/backend/utils/adt/pgstatfuncs.c
> *** ../cvs-pgsql/src/backend/utils/adt/pgstatfuncs.c    Tue Aug 19 23:00:17 2003
> --- ./src/backend/utils/adt/pgstatfuncs.c    Wed Sep 10 00:26:35 2003
> ***************
> *** 187,193 ****
>       if (fcinfo->resultinfo == NULL ||
>           !IsA(fcinfo->resultinfo, ReturnSetInfo))
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                    errmsg("set-valued function called in context that "
>                           "cannot accept a set")));
>
> --- 187,193 ----
>       if (fcinfo->resultinfo == NULL ||
>           !IsA(fcinfo->resultinfo, ReturnSetInfo))
>           ereport(ERROR,
> !                 (errcode(ERRCODE_SYNTAX_ERROR),
>                    errmsg("set-valued function called in context that "
>                           "cannot accept a set")));
>

See above.

> diff -cr ../cvs-pgsql/src/backend/utils/adt/ri_triggers.c ./src/backend/utils/adt/ri_triggers.c
> *** ../cvs-pgsql/src/backend/utils/adt/ri_triggers.c    Tue Aug 19 23:00:18 2003
> --- ./src/backend/utils/adt/ri_triggers.c    Wed Sep 10 00:45:07 2003
> ***************
> *** 3009,3015 ****
>
>       if (spi_err)
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                    errmsg("referential integrity query on \"%s\" from constraint \"%s\" on \"%s\" gave unexpected
result",
>                           RelationGetRelationName(pk_rel),
>                           constrname,
> --- 3009,3015 ----
>
>       if (spi_err)
>           ereport(ERROR,
> !                 (errcode(ERRCODE_INTERNAL_ERROR),
>                    errmsg("referential integrity query on \"%s\" from constraint \"%s\" on \"%s\" gave unexpected
result",
>                           RelationGetRelationName(pk_rel),
>                           constrname,

I don't see a "feature" here.

> diff -cr ../cvs-pgsql/src/backend/utils/adt/ruleutils.c ./src/backend/utils/adt/ruleutils.c
> *** ../cvs-pgsql/src/backend/utils/adt/ruleutils.c    Tue Aug 19 23:00:19 2003
> --- ./src/backend/utils/adt/ruleutils.c    Wed Sep 10 00:29:33 2003
> ***************
> *** 1098,1105 ****
>               }
>           default:
>               ereport(ERROR,
> !                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> !                      errmsg("unsupported constraint type \"%c\"",
>                               conForm->contype)));
>               break;
>       }
> --- 1098,1105 ----
>               }
>           default:
>               ereport(ERROR,
> !                     (errcode(ERRCODE_INTERNAL_ERROR),
> !                      errmsg("invalid constraint type \"%c\"",
>                               conForm->contype)));
>               break;
>       }

This error speaks of bogus values in a system table.

> diff -cr ../cvs-pgsql/src/backend/utils/adt/sets.c ./src/backend/utils/adt/sets.c
> *** ../cvs-pgsql/src/backend/utils/adt/sets.c    Tue Aug 19 23:00:20 2003
> --- ./src/backend/utils/adt/sets.c    Wed Sep 10 00:29:53 2003
> ***************
> *** 203,209 ****
>               rsi->isDone = isDone;
>           else
>               ereport(ERROR,
> !                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                        errmsg("set-valued function called in context that "
>                               "cannot accept a set")));
>       }
> --- 203,209 ----
>               rsi->isDone = isDone;
>           else
>               ereport(ERROR,
> !                     (errcode(ERRCODE_SYNTAX_ERROR),
>                        errmsg("set-valued function called in context that "
>                               "cannot accept a set")));
>       }

See above.

> diff -cr ../cvs-pgsql/src/backend/utils/adt/varbit.c ./src/backend/utils/adt/varbit.c
> *** ../cvs-pgsql/src/backend/utils/adt/varbit.c    Tue Aug 19 23:00:20 2003
> --- ./src/backend/utils/adt/varbit.c    Wed Sep 10 00:44:13 2003
> ***************
> *** 901,907 ****
>       bitlen2 = VARBITLEN(arg2);
>       if (bitlen1 != bitlen2)
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                    errmsg("cannot AND bit strings of different sizes")));
>
>       len = VARSIZE(arg1);
> --- 901,907 ----
>       bitlen2 = VARBITLEN(arg2);
>       if (bitlen1 != bitlen2)
>           ereport(ERROR,
> !                 (errcode(ERRCODE_SYNTAX_ERROR),
>                    errmsg("cannot AND bit strings of different sizes")));
>
>       len = VARSIZE(arg1);
> ***************
> *** 942,948 ****
>       bitlen2 = VARBITLEN(arg2);
>       if (bitlen1 != bitlen2)
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                    errmsg("cannot OR bit strings of different sizes")));
>       len = VARSIZE(arg1);
>       result = (VarBit *) palloc(len);
> --- 942,948 ----
>       bitlen2 = VARBITLEN(arg2);
>       if (bitlen1 != bitlen2)
>           ereport(ERROR,
> !                 (errcode(ERRCODE_SYNTAX_ERROR),
>                    errmsg("cannot OR bit strings of different sizes")));
>       len = VARSIZE(arg1);
>       result = (VarBit *) palloc(len);
> ***************
> *** 988,994 ****
>       bitlen2 = VARBITLEN(arg2);
>       if (bitlen1 != bitlen2)
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                    errmsg("cannot XOR bit strings of different sizes")));
>
>       len = VARSIZE(arg1);
> --- 988,994 ----
>       bitlen2 = VARBITLEN(arg2);
>       if (bitlen1 != bitlen2)
>           ereport(ERROR,
> !                 (errcode(ERRCODE_SYNTAX_ERROR),
>                    errmsg("cannot XOR bit strings of different sizes")));
>
>       len = VARSIZE(arg1);

We once decided (for better or worse) that bit string operations would
only be defined for certain operators.  It's not that under the current
design plan we are trying to get better here.  We simply decided that
certain combinations of input are invalid.

> diff -cr ../cvs-pgsql/src/backend/utils/fmgr/funcapi.c ./src/backend/utils/fmgr/funcapi.c
> *** ../cvs-pgsql/src/backend/utils/fmgr/funcapi.c    Tue Aug 19 23:00:22 2003
> --- ./src/backend/utils/fmgr/funcapi.c    Wed Sep 10 00:24:32 2003
> ***************
> *** 34,40 ****
>        */
>       if (fcinfo->resultinfo == NULL || !IsA(fcinfo->resultinfo, ReturnSetInfo))
>           ereport(ERROR,
> !                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>                    errmsg("set-valued function called in context that cannot accept a set")));
>
>       if (fcinfo->flinfo->fn_extra == NULL)
> --- 34,40 ----
>        */
>       if (fcinfo->resultinfo == NULL || !IsA(fcinfo->resultinfo, ReturnSetInfo))
>           ereport(ERROR,
> !                 (errcode(ERRCODE_SYNTAX_ERROR),
>                    errmsg("set-valued function called in context that cannot accept a set")));
>
>       if (fcinfo->flinfo->fn_extra == NULL)

Man, this really should be centralized somewhere. :-)

--
Peter Eisentraut   peter_e@gmx.net