Remove reg* pseudotype columns; add object info functions

Reconciles the substantive feature delta from new_features (PR #2) onto the
current 'stable' baseline (post PR #5/#16: pgxn-tools testing, cat_tools
0.3.0, and the linter):

- _object_reference._object_oid: drop the per-catalog regclass/regconfig/
  regdictionary/regnamespace/regoperator/regprocedure/regtype columns and
  their unique indexes plus the count_nulls-backed null_count trigger that
  enforced "exactly one is set". classid is now plain oid and object_oid
  (also NOT NULL) is the sole identifier column, so there's nothing left to
  arbitrate between.
- _object_reference._object_v / _object_v__for_update: drop the reg* columns
  from the column list to match.
- _object_reference._object_oid__add: replace the dynamic, format()-built
  INSERT that picked a reg* column based on cat_tools.object__reg_type()
  with a plain INSERT into object_oid.
- Drop the count_nulls search_path DO block (dead now that the trigger using
  it is gone) and the count_nulls dependency throughout (control, Makefile,
  test setup).
- Add object_reference.object__describe()/object__identity(), thin wrappers
  around pg_describe_object()/pg_identify_object(); and object__cleanup(),
  which best-effort deletes an object record (ignoring foreign_key_violation
  if it's still referenced elsewhere). Wire object__cleanup() up to a new
  AFTER DELETE trigger on object_group__object so removing an object from
  its last group automatically attempts cleanup.
- _object_v__for_update (the getsert core): refuse to track objects living
  in a pg_temp*/pg_toast_temp* schema, since a tracked reference would
  outlive the temporary object it points to.
- test/sql/object_group.sql: switch the two scratch tables from TEMP to
  regular tables (object__getsert now rejects temp objects) and add
  coverage for the new automatic-cleanup trigger.
- test/sql/base.sql: replace the count_nulls-relocation test (relocation
  was already unsupported and the whole extension no longer depends on
  count_nulls) with coverage for object_oid, object__describe(),
  object__identity(), and temp-object rejection.

sql/object_reference--0.1.0.sql (the frozen historical release) and the
META files are untouched. default_version stays 'stable'; sql/object_reference--stable.sql
is regenerated to match sql/object_reference.sql. make lint and make test
(including the dump/restore test) pass on both PostgreSQL 12 and 17.

Supersedes PR #2 (new_features) and, for the update/upgrade test
infrastructure built on top of it, sets up the rebuild of PR #3.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: jnasbyupgrade

Makefile

@@ -3,7 +3,7 @@ include pgxntool/base.mk
 testdeps: $(wildcard test/*.sql test/helpers/*.sql) # Be careful not to include directories in this
 testdeps: test_factory
 
-install: cat_tools count_nulls
+install: cat_tools
 
 # pgxntool's check-stale-expected target (added in pgxntool 2.2.0) depends on
 # installcheck but is listed before install in TEST_DEPS, and Make evaluates a
@@ -22,11 +22,6 @@ cat_tools: $(DESTDIR)$(datadir)/extension/cat_tools.control
 $(DESTDIR)$(datadir)/extension/cat_tools.control:
 	pgxn install --unstable cat_tools
 
-.PHONY: count_nulls
-count_nulls: $(DESTDIR)$(datadir)/extension/count_nulls.control
-$(DESTDIR)$(datadir)/extension/count_nulls.control:
-	pgxn install --unstable count_nulls
-
 .PHONY: test_factory
 test_factory: $(DESTDIR)$(datadir)/extension/test_factory.control
 $(DESTDIR)$(datadir)/extension/test_factory.control:

object_reference.control

@@ -2,4 +2,4 @@ comment = 'Provides reference IDs for database objects'
 default_version = 'stable'
 relocatable = false
 schema = 'object_reference'
-requires = 'cat_tools, count_nulls'
+requires = 'cat_tools'

sql/object_reference--stable.sql

@@ -3,17 +3,6 @@
 \echo You really, REALLY do NOT want to try and load this via psql!!!
 \echo It will FAIL during pg_dump! \quit
 
--- This BS is because count_nulls is relocatable, so could be in any schema
-DO $$
-BEGIN
-  RAISE DEBUG 'initial search_path = %', current_setting('search_path');
-  PERFORM set_config('search_path', current_setting('search_path') || ', ' || extnamespace::regnamespace::text, true) -- true = local only
-    FROM pg_extension
-    WHERE extname = 'count_nulls'
-  ;
-  RAISE DEBUG 'search_path changed to %', current_setting('search_path');
-END
-$$;
 /*
 DO $$
 DECLARE
@@ -192,58 +181,19 @@ GRANT REFERENCES ON _object_reference.object TO object_reference__dependency;
 
 CREATE TABLE _object_reference._object_oid(
   object_id       int                     PRIMARY KEY REFERENCES _object_reference.object ON DELETE CASCADE ON UPDATE CASCADE
-  , classid       regclass                NOT NULL
+  , classid       oid                     NOT NULL
   /* TODO: needs to be a trigger
     CONSTRAINT classid_must_match__object__address_classid
       CHECK( classid IS NOT DISTINCT FROM cat_tools.object__address_classid(object_type) )
     */
   , objid         oid                     NOT NULL
   , objsubid      int                     NOT NULL
     CONSTRAINT objid_must_match CHECK( -- _object_reference._sanity() depends on this!
-      objid IS NOT DISTINCT FROM coalesce(
-        regclass::oid -- Need to cast first item to generic OID
-        , regconfig
-        , regdictionary
-        , regnamespace -- SED: REQUIRES 9.5!
-        , regoperator
-        , regprocedure
-        , regtype
-        , object_oid
-      )
+      objid IS NOT DISTINCT FROM object_oid
     )
   , CONSTRAINT object__u_classid__objid__objsubid UNIQUE( classid, objid, objsubid )
-  , regclass      regclass
-    CONSTRAINT regclass_classid CHECK( regclass IS NULL OR classid = cat_tools.object__reg_type_catalog('regclass') )
-  , regconfig     regconfig
-    CONSTRAINT regconfig_classid CHECK( regconfig IS NULL OR classid = cat_tools.object__reg_type_catalog('regconfig') )
-  , regdictionary regdictionary
-    CONSTRAINT regdictionary_classid CHECK( regdictionary IS NULL OR classid = cat_tools.object__reg_type_catalog('regdictionary') )
-  , regnamespace  regnamespace -- SED: REQUIRES 9.5!
-    CONSTRAINT regnamespace_classid CHECK( regnamespace IS NULL OR classid = cat_tools.object__reg_type_catalog('regnamespace') ) -- SED: REQUIRES 9.5!
-  , regoperator   regoperator
-    CONSTRAINT regoperator_classid CHECK( regoperator IS NULL OR classid = cat_tools.object__reg_type_catalog('regoperator') )
-  , regprocedure  regprocedure
-    CONSTRAINT regprocedure_classid CHECK( regprocedure IS NULL OR classid = cat_tools.object__reg_type_catalog('regprocedure') )
-  -- I don't think we should ever have regrole since we can't create event triggers on it
---  , regrole       regrole
-  , regtype       regtype
-    CONSTRAINT regtype_classid CHECK( regtype IS NULL OR classid = cat_tools.object__reg_type_catalog('regtype') )
-  , object_oid    oid
+  , object_oid    oid                     NOT NULL
 );
-CREATE TRIGGER null_count
-  AFTER INSERT OR UPDATE
-  ON _object_reference._object_oid
-  FOR EACH ROW EXECUTE PROCEDURE not_null_count_trigger(
-    5 -- First 4 fields, + 1
-    , 'only one object reference field may be set'
-  )
-;
-CREATE UNIQUE INDEX _object_oid__u_regclass ON _object_reference._object_oid(regclass) WHERE regclass IS NOT NULL;
-CREATE UNIQUE INDEX _object_oid__u_regconfig ON _object_reference._object_oid(regconfig) WHERE regconfig IS NOT NULL;
-CREATE UNIQUE INDEX _object_oid__u_regdictionary ON _object_reference._object_oid(regdictionary) WHERE regdictionary IS NOT NULL;
-CREATE UNIQUE INDEX _object_oid__u_regoperator ON _object_reference._object_oid(regoperator) WHERE regoperator IS NOT NULL;
-CREATE UNIQUE INDEX _object_oid__u_regprocedure ON _object_reference._object_oid(regprocedure) WHERE regprocedure IS NOT NULL;
-CREATE UNIQUE INDEX _object_oid__u_regtype ON _object_reference._object_oid(regtype) WHERE regtype IS NOT NULL;
 
 SELECT __object_reference.create_function(
   '_object_reference._sanity'
@@ -303,13 +253,6 @@ CREATE VIEW _object_reference._object_v AS
       , i.classid
       , i.objid
       , i.objsubid
-      , i.regclass
-      , i.regconfig
-      , i.regdictionary
-      , i.regnamespace
-      , i.regoperator
-      , i.regprocedure
-      , i.regtype
       , i.object_oid
       , s.*
     FROM _object_reference.object o
@@ -325,13 +268,6 @@ CREATE VIEW _object_reference._object_v__for_update AS
       , i.classid
       , i.objid
       , i.objsubid
-      , i.regclass
-      , i.regconfig
-      , i.regdictionary
-      , i.regnamespace
-      , i.regoperator
-      , i.regprocedure
-      , i.regtype
       , i.object_oid
       , s.*
     FROM _object_reference.object o
@@ -363,26 +299,9 @@ BEGIN
       WHERE o.object_id = _object_oid__add.object_id
     ;
   END IF;
-  DECLARE
-    c_reg_type name := cat_tools.object__reg_type(object_type); -- Verifies regtype is supported, if there is one
-    c_oid_field CONSTANT name := coalesce(c_reg_type, 'object_oid');
-
-    c_oid_insert CONSTANT text := format(
-      --USING object_id, classid, objid, objsubid
-        $$INSERT INTO _object_reference._object_oid(object_id, classid, objid, objsubid, %I)
-            SELECT $1, $2, $3, $4, $3::%I$$
-        , c_oid_field
-        , coalesce(c_reg_type, 'oid')
-      )
-    ;
   BEGIN
-    RAISE DEBUG E'%\n    USING  %, %, %, %'
-      , c_oid_insert
-      , object_id, classid, objid, objsubid
-    ;
-    EXECUTE c_oid_insert
-      USING object_id, classid, objid, objsubid
-    ;
+    INSERT INTO _object_reference._object_oid(object_id, classid, objid, objsubid, object_oid)
+      VALUES (object_id, classid, objid, objsubid, objid);
 
     SELECT INTO STRICT r_object_v -- Record better exist!
         *
@@ -632,6 +551,24 @@ CREATE TABLE _object_reference.object_group__object(
 );
 SELECT __object_reference.safe_dump('_object_reference.object_group__object');
 
+-- Trigger function for automatic object cleanup
+SELECT __object_reference.create_function(
+  '_object_reference._object_group__object__cleanup_trigger'
+  , ''
+  , 'trigger LANGUAGE plpgsql'
+  , $body$
+BEGIN
+  PERFORM object_reference.object__cleanup(OLD.object_id);
+  RETURN OLD;
+END
+$body$
+  , 'Trigger function to automatically attempt cleanup of objects when removed from groups.'
+);
+CREATE TRIGGER object_group__object__cleanup
+  AFTER DELETE ON _object_reference.object_group__object
+  FOR EACH ROW
+  EXECUTE FUNCTION _object_reference._object_group__object__cleanup_trigger();
+
 -- __get
 SELECT __object_reference.create_function(
   'object_reference.object_group__get'
@@ -836,6 +773,69 @@ $body$
   , 'object_reference__dependency'
 );
 
+/*
+ * OBJECT INFO FUNCTIONS
+ */
+SELECT __object_reference.create_function(
+  'object_reference.object__describe'
+  , $args$
+  object_id int
+$args$
+  , 'text LANGUAGE sql'
+  , $body$
+SELECT pg_catalog.pg_describe_object(
+  o.classid
+  , o.objid
+  , o.objsubid
+)
+FROM _object_reference._object_oid o
+WHERE o.object_id = $1
+$body$
+  , 'Return a human-readable description of the object, matching pg_describe_object() format.'
+  , 'object_reference__usage'
+);
+
+SELECT __object_reference.create_function(
+  'object_reference.object__identity'
+  , $args$
+  object_id int
+  , OUT type text
+  , OUT schema text
+  , OUT name text
+  , OUT identity text
+$args$
+  , 'record LANGUAGE sql'
+  , $body$
+SELECT
+  i.type::text
+  , i.schema::text
+  , i.name::text
+  , i.identity::text
+FROM _object_reference._object_oid o
+  , LATERAL pg_catalog.pg_identify_object(o.classid, o.objid, o.objsubid) i
+WHERE o.object_id = $1
+$body$
+  , 'Return object identification information matching pg_identify_object() format.'
+  , 'object_reference__usage'
+);
+SELECT __object_reference.create_function(
+  'object_reference.object__cleanup'
+  , $args$
+  object_id int
+$args$
+  , 'void LANGUAGE plpgsql'
+  , $body$
+BEGIN
+  DELETE FROM _object_reference.object WHERE object.object_id = object__cleanup.object_id;
+EXCEPTION WHEN foreign_key_violation THEN
+  -- Object is still referenced elsewhere, ignore the error
+  NULL;
+END
+$body$
+  , 'Attempts to delete an object from the tracking system. Silently returns if the object is still referenced by other tables.'
+  , 'object_reference__usage'
+);
+
 /*
  * OBJECT GETSERT
  */
@@ -855,6 +855,7 @@ DECLARE
 
   r_object_v _object_reference._object_v;
   r_address record;
+  r_identity record;
 
   did_insert boolean := false;
 
@@ -883,6 +884,15 @@ BEGIN
     ;
   END IF;
 
+  -- Refuse to track objects in temporary schemas
+  SELECT INTO r_identity * FROM pg_catalog.pg_identify_object(c_classid, objid, objsubid);
+  IF r_identity.schema IS NOT NULL AND (r_identity.schema LIKE 'pg_temp%' OR r_identity.schema LIKE 'pg_toast_temp%') THEN
+    RAISE 'cannot track temporary object'
+      USING DETAIL = format('object %s is in temporary schema %s', r_identity.identity, r_identity.schema)
+      , ERRCODE = 'feature_not_supported'
+    ;
+  END IF;
+
   -- Ensure the object record exists
   SELECT INTO r_object_v
       *