From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Dunstan <andrew@dunslane.net>
cc: pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Declare assorted array functions using anycompatible not
 anyelem
In-reply-to: <dc77bfb2-3b98-c3e5-a825-6c087d51f51c@dunslane.net>
References: <E1kaQ2c-0005lx-Eg@gemulon.postgresql.org>
 <fff35eb5-765c-3e60-3a2a-45ba5f88777d@dunslane.net>
 <1999748.1604957386@sss.pgh.pa.us>
 <b300679b-6410-9124-271c-73893a2c3a1f@dunslane.net>
 <2001798.1604960149@sss.pgh.pa.us>
 <52030649-c25c-c4e6-8316-2fd4f9a24f8b@dunslane.net>
 <2008195.1604961694@sss.pgh.pa.us>
 <dc77bfb2-3b98-c3e5-a825-6c087d51f51c@dunslane.net>
Comments: In-reply-to Andrew Dunstan <andrew@dunslane.net>
	message dated "Tue, 10 Nov 2020 08:45:06 -0500"
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Date: Tue, 10 Nov 2020 15:31:43 -0500
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Andrew Dunstan <andrew@dunslane.net> writes:
> On 11/9/20 5:41 PM, Tom Lane wrote:
>> What I have in mind to apply to 9.5 through 13 is per attached.

> You also need to modify first_el_agg_any.

... doh.  That one is a little messier because there's no equally useful
substitute function.  What I'm inclined to do for that is to add a
SQL-language wrapper to reproduce the old signature for array_append.
As attached.  (I'm keeping this separate from the other patch, since
this doesn't go back as far.)

> Here's what I have working on crake::

OK.

			regards, tom lane


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diff --git a/src/test/regress/expected/polymorphism.out b/src/test/regress=
/expected/polymorphism.out
index 2c3bb0a60b..628a39612a 100644
--- a/src/test/regress/expected/polymorphism.out
+++ b/src/test/regress/expected/polymorphism.out
@@ -786,16 +786,18 @@ create aggregate build_group(int8, integer) (
   STYPE =3D int8[]
 );
 -- check proper resolution of data types for polymorphic transfn/finalfn
-create function first_el(anycompatiblearray) returns anycompatible as
+create function first_el_transfn(anyarray, anyelement) returns anyarray a=
s
+'select $1 || $2' language sql immutable;
+create function first_el(anyarray) returns anyelement as
 'select $1[1]' language sql strict immutable;
 create aggregate first_el_agg_f8(float8) (
   SFUNC =3D array_append,
   STYPE =3D float8[],
   FINALFUNC =3D first_el
 );
-create aggregate first_el_agg_any(anycompatible) (
-  SFUNC =3D array_append,
-  STYPE =3D anycompatiblearray,
+create aggregate first_el_agg_any(anyelement) (
+  SFUNC =3D first_el_transfn,
+  STYPE =3D anyarray,
   FINALFUNC =3D first_el
 );
 select first_el_agg_f8(x::float8) from generate_series(1,10) x;
diff --git a/src/test/regress/sql/polymorphism.sql b/src/test/regress/sql/=
polymorphism.sql
index 70a21c8978..d98a74c3f6 100644
--- a/src/test/regress/sql/polymorphism.sql
+++ b/src/test/regress/sql/polymorphism.sql
@@ -549,7 +549,10 @@ create aggregate build_group(int8, integer) (
 =

 -- check proper resolution of data types for polymorphic transfn/finalfn
 =

-create function first_el(anycompatiblearray) returns anycompatible as
+create function first_el_transfn(anyarray, anyelement) returns anyarray a=
s
+'select $1 || $2' language sql immutable;
+
+create function first_el(anyarray) returns anyelement as
 'select $1[1]' language sql strict immutable;
 =

 create aggregate first_el_agg_f8(float8) (
@@ -558,9 +561,9 @@ create aggregate first_el_agg_f8(float8) (
   FINALFUNC =3D first_el
 );
 =

-create aggregate first_el_agg_any(anycompatible) (
-  SFUNC =3D array_append,
-  STYPE =3D anycompatiblearray,
+create aggregate first_el_agg_any(anyelement) (
+  SFUNC =3D first_el_transfn,
+  STYPE =3D anyarray,
   FINALFUNC =3D first_el
 );
 =


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diff --git a/src/test/regress/expected/polymorphism.out b/src/test/regress=
/expected/polymorphism.out
index 1ff40764d9..236b2532b3 100644
--- a/src/test/regress/expected/polymorphism.out
+++ b/src/test/regress/expected/polymorphism.out
@@ -786,6 +786,8 @@ create aggregate build_group(int8, integer) (
   STYPE =3D int8[]
 );
 -- check proper resolution of data types for polymorphic transfn/finalfn
+create function first_el_transfn(anyarray, anyelement) returns anyarray a=
s
+'select $1 || $2' language sql immutable;
 create function first_el(anyarray) returns anyelement as
 'select $1[1]' language sql strict immutable;
 create aggregate first_el_agg_f8(float8) (
@@ -794,7 +796,7 @@ create aggregate first_el_agg_f8(float8) (
   FINALFUNC =3D first_el
 );
 create aggregate first_el_agg_any(anyelement) (
-  SFUNC =3D array_append,
+  SFUNC =3D first_el_transfn,
   STYPE =3D anyarray,
   FINALFUNC =3D first_el
 );
diff --git a/src/test/regress/sql/polymorphism.sql b/src/test/regress/sql/=
polymorphism.sql
index e5222f1f81..d2e302c330 100644
--- a/src/test/regress/sql/polymorphism.sql
+++ b/src/test/regress/sql/polymorphism.sql
@@ -549,6 +549,9 @@ create aggregate build_group(int8, integer) (
 =

 -- check proper resolution of data types for polymorphic transfn/finalfn
 =

+create function first_el_transfn(anyarray, anyelement) returns anyarray a=
s
+'select $1 || $2' language sql immutable;
+
 create function first_el(anyarray) returns anyelement as
 'select $1[1]' language sql strict immutable;
 =

@@ -559,7 +562,7 @@ create aggregate first_el_agg_f8(float8) (
 );
 =

 create aggregate first_el_agg_any(anyelement) (
-  SFUNC =3D array_append,
+  SFUNC =3D first_el_transfn,
   STYPE =3D anyarray,
   FINALFUNC =3D first_el
 );

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