Make DROP IF EXISTS more consistently not fail

Some cases were still reporting errors and aborting, instead of a NOTICE
that the object was being skipped.  This makes it more difficult to
cleanly handle pg_dump --clean, so change that to instead skip missing
objects properly.

Per bug #7873 reported by Dave Rolsky; apparently this affects a large
number of users.

Authors: Pavel Stehule and Dean Rasheed.  Some tweaks by Álvaro Herrera

src/backend/catalog/namespace.c

@@ -906,10 +906,15 @@ TypeIsVisible(Oid typid)
  * with oid = 0 that represents a set of such conflicting candidates.
  * The caller might end up discarding such an entry anyway, but if it selects
  * such an entry it should react as though the call were ambiguous.
+ *
+ * If missing_ok is true, an empty list (NULL) is returned if the name was
+ * schema- qualified with a schema that does not exist.  Likewise if no
+ * candidate is found for other reasons.
  */
 FuncCandidateList
 FuncnameGetCandidates(List *names, int nargs, List *argnames,
-					  bool expand_variadic, bool expand_defaults)
+					  bool expand_variadic, bool expand_defaults,
+					  bool missing_ok)
 {
 	FuncCandidateList resultList = NULL;
 	bool		any_special = false;
@@ -928,7 +933,9 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 	if (schemaname)
 	{
 		/* use exact schema given */
-		namespaceId = LookupExplicitNamespace(schemaname, false);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (!OidIsValid(namespaceId))
+			return NULL;
 	}
 	else
 	{
@@ -1414,7 +1421,7 @@ FunctionIsVisible(Oid funcid)
 		visible = false;
 
 		clist = FuncnameGetCandidates(list_make1(makeString(proname)),
-									  nargs, NIL, false, false);
+									  nargs, NIL, false, false, false);
 
 		for (; clist; clist = clist->next)
 		{
@@ -1443,7 +1450,8 @@ FunctionIsVisible(Oid funcid)
  * a postfix op.
  *
  * If the operator name is not schema-qualified, it is sought in the current
- * namespace search path.
+ * namespace search path.  If the name is schema-qualified and the given
+ * schema does not exist, InvalidOid is returned.
  */
 Oid
 OpernameGetOprid(List *names, Oid oprleft, Oid oprright)
@@ -1460,9 +1468,12 @@ OpernameGetOprid(List *names, Oid oprleft, Oid oprright)
 	{
 		/* search only in exact schema given */
 		Oid			namespaceId;
+
+		namespaceId = LookupExplicitNamespace(schemaname, true);
+		if (OidIsValid(namespaceId))
+		{
 			HeapTuple	opertup;
 
-		namespaceId = LookupExplicitNamespace(schemaname, false);
 			opertup = SearchSysCache4(OPERNAMENSP,
 									  CStringGetDatum(opername),
 									  ObjectIdGetDatum(oprleft),
@@ -1475,6 +1486,8 @@ OpernameGetOprid(List *names, Oid oprleft, Oid oprright)
 				ReleaseSysCache(opertup);
 				return result;
 			}
+		}
+
 		return InvalidOid;
 	}
 
@@ -1729,7 +1742,7 @@ OperatorIsVisible(Oid oprid)
 		 * If it is in the path, it might still not be visible; it could be
 		 * hidden by another operator of the same name and arguments earlier
 		 * in the path.  So we must do a slow check to see if this is the same
-		 * operator that would be found by OpernameGetOprId.
+		 * operator that would be found by OpernameGetOprid.
 		 */
 		char	   *oprname = NameStr(oprform->oprname);
 

src/backend/catalog/objectaddress.c

@@ -450,7 +450,7 @@ static void getRelationIdentity(StringInfo buffer, Oid relid);
  * sub-object is looked up, the parent object will be locked instead.
  *
  * If the object is a relation or a child object of a relation (e.g. an
- * attribute or contraint), the relation is also opened and *relp receives
+ * attribute or constraint), the relation is also opened and *relp receives
  * the open relcache entry pointer; otherwise, *relp is set to NULL.  This
  * is a bit grotty but it makes life simpler, since the caller will
  * typically need the relcache entry too.  Caller must close the relcache
@@ -458,9 +458,20 @@ static void getRelationIdentity(StringInfo buffer, Oid relid);
  * if the target object is the relation itself or an attribute, but for other
  * child objects, only AccessShareLock is acquired on the relation.
  *
+ * If the object is not found, an error is thrown, unless missing_ok is
+ * true.  In this case, no lock is acquired, relp is set to NULL, and the
+ * returned address has objectId set to InvalidOid.
+ *
  * We don't currently provide a function to release the locks acquired here;
  * typically, the lock must be held until commit to guard against a concurrent
  * drop operation.
+ *
+ * Note: If the object is not found, we don't give any indication of the
+ * reason.	(It might have been a missing schema if the name was qualified, or
+ * an inexistant type name in case of a cast, function or operator; etc).
+ * Currently there is only one caller that might be interested in such info, so
+ * we don't spend much effort here.  If more callers start to care, it might be
+ * better to add some support for that in this function.
  */
 ObjectAddress
 get_object_address(ObjectType objtype, List *objname, List *objargs,
@@ -580,9 +591,11 @@ get_object_address(ObjectType objtype, List *objname, List *objargs,
 				{
 					TypeName   *sourcetype = (TypeName *) linitial(objname);
 					TypeName   *targettype = (TypeName *) linitial(objargs);
-					Oid			sourcetypeid = typenameTypeId(NULL, sourcetype);
-					Oid			targettypeid = typenameTypeId(NULL, targettype);
+					Oid			sourcetypeid;
+					Oid			targettypeid;
 
+					sourcetypeid = LookupTypeNameOid(NULL, sourcetype, missing_ok);
+					targettypeid = LookupTypeNameOid(NULL, targettype, missing_ok);
 					address.classId = CastRelationId;
 					address.objectId =
 						get_cast_oid(sourcetypeid, targettypeid, missing_ok);
@@ -942,26 +955,31 @@ get_object_address_relobject(ObjectType objtype, List *objname,
 
 		/* Extract relation name and open relation. */
 		relname = list_truncate(list_copy(objname), nnames - 1);
-		relation = heap_openrv(makeRangeVarFromNameList(relname),
-							   AccessShareLock);
-		reloid = RelationGetRelid(relation);
+		relation = heap_openrv_extended(makeRangeVarFromNameList(relname),
+										AccessShareLock,
+										missing_ok);
+
+		reloid = relation ? RelationGetRelid(relation) : InvalidOid;
 
 		switch (objtype)
 		{
 			case OBJECT_RULE:
 				address.classId = RewriteRelationId;
-				address.objectId = get_rewrite_oid(reloid, depname, missing_ok);
+				address.objectId = relation ?
+					get_rewrite_oid(reloid, depname, missing_ok) : InvalidOid;
 				address.objectSubId = 0;
 				break;
 			case OBJECT_TRIGGER:
 				address.classId = TriggerRelationId;
-				address.objectId = get_trigger_oid(reloid, depname, missing_ok);
+				address.objectId = relation ?
+					get_trigger_oid(reloid, depname, missing_ok) : InvalidOid;
 				address.objectSubId = 0;
 				break;
 			case OBJECT_CONSTRAINT:
 				address.classId = ConstraintRelationId;
-				address.objectId =
-					get_relation_constraint_oid(reloid, depname, missing_ok);
+				address.objectId = relation ?
+					get_relation_constraint_oid(reloid, depname, missing_ok) :
+					InvalidOid;
 				address.objectSubId = 0;
 				break;
 			default:
@@ -975,7 +993,9 @@ get_object_address_relobject(ObjectType objtype, List *objname,
 		/* Avoid relcache leak when object not found. */
 		if (!OidIsValid(address.objectId))
 		{
+			if (relation != NULL)
 				heap_close(relation, AccessShareLock);
+
 			relation = NULL;	/* department of accident prevention */
 			return address;
 		}
@@ -1008,6 +1028,7 @@ get_object_address_attribute(ObjectType objtype, List *objname,
 				 errmsg("column name must be qualified")));
 	attname = strVal(lfirst(list_tail(objname)));
 	relname = list_truncate(list_copy(objname), list_length(objname) - 1);
+	/* XXX no missing_ok support here */
 	relation = relation_openrv(makeRangeVarFromNameList(relname), lockmode);
 	reloid = RelationGetRelid(relation);
 
@@ -1053,7 +1074,7 @@ get_object_address_type(ObjectType objtype,
 	address.objectId = InvalidOid;
 	address.objectSubId = 0;
 
-	tup = LookupTypeName(NULL, typename, NULL);
+	tup = LookupTypeName(NULL, typename, NULL, missing_ok);
 	if (!HeapTupleIsValid(tup))
 	{
 		if (!missing_ok)
@@ -1090,6 +1111,7 @@ get_object_address_opcf(ObjectType objtype,
 	ObjectAddress address;
 
 	Assert(list_length(objargs) == 1);
+	/* XXX no missing_ok support here */
 	amoid = get_am_oid(strVal(linitial(objargs)), false);
 
 	switch (objtype)

src/backend/commands/functioncmds.c

@@ -86,7 +86,7 @@ compute_return_type(TypeName *returnType, Oid languageOid,
 	Type		typtup;
 	AclResult	aclresult;
 
-	typtup = LookupTypeName(NULL, returnType, NULL);
+	typtup = LookupTypeName(NULL, returnType, NULL, false);
 
 	if (typtup)
 	{
@@ -224,7 +224,7 @@ interpret_function_parameter_list(List *parameters,
 		Type		typtup;
 		AclResult	aclresult;
 
-		typtup = LookupTypeName(NULL, t, NULL);
+		typtup = LookupTypeName(NULL, t, NULL, false);
 		if (typtup)
 		{
 			if (!((Form_pg_type) GETSTRUCT(typtup))->typisdefined)

src/backend/commands/opclasscmds.c

@@ -103,7 +103,10 @@ OpFamilyCacheLookup(Oid amID, List *opfamilyname, bool missing_ok)
 		/* Look in specific schema only */
 		Oid			namespaceId;
 
-		namespaceId = LookupExplicitNamespace(schemaname, false);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (!OidIsValid(namespaceId))
+			htup = NULL;
+		else
 			htup = SearchSysCache3(OPFAMILYAMNAMENSP,
 								   ObjectIdGetDatum(amID),
 								   PointerGetDatum(opfname),
@@ -179,7 +182,10 @@ OpClassCacheLookup(Oid amID, List *opclassname, bool missing_ok)
 		/* Look in specific schema only */
 		Oid			namespaceId;
 
-		namespaceId = LookupExplicitNamespace(schemaname, false);
+		namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+		if (!OidIsValid(namespaceId))
+			htup = NULL;
+		else
 			htup = SearchSysCache3(CLAAMNAMENSP,
 								   ObjectIdGetDatum(amID),
 								   PointerGetDatum(opcname),

src/backend/commands/tablecmds.c

@@ -690,10 +690,28 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId)
  * non-existent relation
  */
 static void
-DropErrorMsgNonExistent(const char *relname, char rightkind, bool missing_ok)
+DropErrorMsgNonExistent(RangeVar *rel, char rightkind, bool missing_ok)
 {
 	const struct dropmsgstrings *rentry;
 
+	if (rel->schemaname != NULL &&
+		!OidIsValid(LookupNamespaceNoError(rel->schemaname)))
+	{
+		if (!missing_ok)
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_SCHEMA),
+					 errmsg("schema \"%s\" does not exist", rel->schemaname)));
+		}
+		else
+		{
+			ereport(NOTICE,
+					(errmsg("schema \"%s\" does not exist, skipping",
+							rel->schemaname)));
+		}
+		return;
+	}
+
 	for (rentry = dropmsgstringarray; rentry->kind != '\0'; rentry++)
 	{
 		if (rentry->kind == rightkind)
@@ -702,11 +720,11 @@ DropErrorMsgNonExistent(const char *relname, char rightkind, bool missing_ok)
 			{
 				ereport(ERROR,
 						(errcode(rentry->nonexistent_code),
-						 errmsg(rentry->nonexistent_msg, relname)));
+						 errmsg(rentry->nonexistent_msg, rel->relname)));
 			}
 			else
 			{
-				ereport(NOTICE, (errmsg(rentry->skipping_msg, relname)));
+				ereport(NOTICE, (errmsg(rentry->skipping_msg, rel->relname)));
 				break;
 			}
 		}
@@ -845,7 +863,7 @@ RemoveRelations(DropStmt *drop)
 		/* Not there? */
 		if (!OidIsValid(relOid))
 		{
-			DropErrorMsgNonExistent(rel->relname, relkind, drop->missing_ok);
+			DropErrorMsgNonExistent(rel, relkind, drop->missing_ok);
 			continue;
 		}
 

src/backend/commands/typecmds.c

@@ -3246,7 +3246,7 @@ AlterTypeOwner(List *names, Oid newOwnerId, ObjectType objecttype)
 	typename = makeTypeNameFromNameList(names);
 
 	/* Use LookupTypeName here so that shell types can be processed */
-	tup = LookupTypeName(NULL, typename, NULL);
+	tup = LookupTypeName(NULL, typename, NULL, false);
 	if (tup == NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_UNDEFINED_OBJECT),

src/backend/parser/parse_func.c

@@ -1259,7 +1259,8 @@ func_get_detail(List *funcname,
 
 	/* Get list of possible candidates from namespace search */
 	raw_candidates = FuncnameGetCandidates(funcname, nargs, fargnames,
-										   expand_variadic, expand_defaults);
+										   expand_variadic, expand_defaults,
+										   false);
 
 	/*
 	 * Quickly check if there is an exact match to the input datatypes (there
@@ -1714,7 +1715,7 @@ FuncNameAsType(List *funcname)
 	Oid			result;
 	Type		typtup;
 
-	typtup = LookupTypeName(NULL, makeTypeNameFromNameList(funcname), NULL);
+	typtup = LookupTypeName(NULL, makeTypeNameFromNameList(funcname), NULL, false);
 	if (typtup == NULL)
 		return InvalidOid;
 
@@ -1873,7 +1874,7 @@ LookupFuncName(List *funcname, int nargs, const Oid *argtypes, bool noError)
 {
 	FuncCandidateList clist;
 
-	clist = FuncnameGetCandidates(funcname, nargs, NIL, false, false);
+	clist = FuncnameGetCandidates(funcname, nargs, NIL, false, false, noError);
 
 	while (clist)
 	{
@@ -1892,27 +1893,6 @@ LookupFuncName(List *funcname, int nargs, const Oid *argtypes, bool noError)
 	return InvalidOid;
 }
 
-/*
- * LookupTypeNameOid
- *		Convenience routine to look up a type, silently accepting shell types
- */
-static Oid
-LookupTypeNameOid(const TypeName *typename)
-{
-	Oid			result;
-	Type		typtup;
-
-	typtup = LookupTypeName(NULL, typename, NULL);
-	if (typtup == NULL)
-		ereport(ERROR,
-				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				 errmsg("type \"%s\" does not exist",
-						TypeNameToString(typename))));
-	result = typeTypeId(typtup);
-	ReleaseSysCache(typtup);
-	return result;
-}
-
 /*
  * LookupFuncNameTypeNames
  *		Like LookupFuncName, but the argument types are specified by a
@@ -1940,7 +1920,7 @@ LookupFuncNameTypeNames(List *funcname, List *argtypes, bool noError)
 	{
 		TypeName   *t = (TypeName *) lfirst(args_item);
 
-		argoids[i] = LookupTypeNameOid(t);
+		argoids[i] = LookupTypeNameOid(NULL, t, noError);
 		args_item = lnext(args_item);
 	}
 
@@ -1980,7 +1960,7 @@ LookupAggNameTypeNames(List *aggname, List *argtypes, bool noError)
 	{
 		TypeName   *t = (TypeName *) lfirst(lc);
 
-		argoids[i] = LookupTypeNameOid(t);
+		argoids[i] = LookupTypeNameOid(NULL, t, noError);
 		i++;
 	}
 

src/backend/parser/parse_oper.c

@@ -148,12 +148,12 @@ LookupOperNameTypeNames(ParseState *pstate, List *opername,
 	if (oprleft == NULL)
 		leftoid = InvalidOid;
 	else
-		leftoid = typenameTypeId(pstate, oprleft);
+		leftoid = LookupTypeNameOid(pstate, oprleft, noError);
 
 	if (oprright == NULL)
 		rightoid = InvalidOid;
 	else
-		rightoid = typenameTypeId(pstate, oprright);
+		rightoid = LookupTypeNameOid(pstate, oprright, noError);
 
 	return LookupOperName(pstate, opername, leftoid, rightoid,
 						  noError, location);

src/backend/parser/parse_type.c

@@ -56,7 +56,7 @@ static int32 typenameTypeMod(ParseState *pstate, const TypeName *typeName,
  */
 Type
 LookupTypeName(ParseState *pstate, const TypeName *typeName,
-			   int32 *typmod_p)
+			   int32 *typmod_p, bool missing_ok)
 {
 	Oid			typoid;
 	HeapTuple	tup;
@@ -116,14 +116,21 @@ LookupTypeName(ParseState *pstate, const TypeName *typeName,
 		 * concurrent DDL.	But taking a lock would carry a performance
 		 * penalty and would also require a permissions check.
 		 */
-		relid = RangeVarGetRelid(rel, NoLock, false);
+		relid = RangeVarGetRelid(rel, NoLock, missing_ok);
 		attnum = get_attnum(relid, field);
 		if (attnum == InvalidAttrNumber)
+		{
+			if (missing_ok)
+				typoid = InvalidOid;
+			else
 				ereport(ERROR,
 						(errcode(ERRCODE_UNDEFINED_COLUMN),
 					errmsg("column \"%s\" of relation \"%s\" does not exist",
 						   field, rel->relname),
 						 parser_errposition(pstate, typeName->location)));
+		}
+		else
+		{
 			typoid = get_atttype(relid, attnum);
 
 			/* this construct should never have an array indicator */
@@ -135,6 +142,7 @@ LookupTypeName(ParseState *pstate, const TypeName *typeName,
 							TypeNameToString(typeName),
 							format_type_be(typoid))));
 		}
+	}
 	else
 	{
 		/* Normal reference to a type name */
@@ -149,10 +157,13 @@ LookupTypeName(ParseState *pstate, const TypeName *typeName,
 			/* Look in specific schema only */
 			Oid			namespaceId;
 
-			namespaceId = LookupExplicitNamespace(schemaname, false);
+			namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+			if (OidIsValid(namespaceId))
 				typoid = GetSysCacheOid2(TYPENAMENSP,
 										 PointerGetDatum(typname),
 										 ObjectIdGetDatum(namespaceId));
+			else
+				typoid = InvalidOid;
 		}
 		else
 		{
@@ -184,6 +195,43 @@ LookupTypeName(ParseState *pstate, const TypeName *typeName,
 	return (Type) tup;
 }
 
+/*
+ * LookupTypeNameOid
+ *		Given a TypeName object, lookup the pg_type syscache entry of the type.
+ *		Returns InvalidOid if no such type can be found.  If the type is found,
+ *		return its Oid.
+ *
+ * NB: direct callers of this function need to be aware that the type OID
+ * returned may correspond to a shell type.  Most code should go through
+ * typenameTypeId instead.
+ *
+ * pstate is only used for error location info, and may be NULL.
+ */
+Oid
+LookupTypeNameOid(ParseState *pstate, const TypeName *typeName, bool missing_ok)
+{
+	Oid			typoid;
+	Type		tup;
+
+	tup = LookupTypeName(pstate, typeName, NULL, missing_ok);
+	if (tup == NULL)
+	{
+		if (!missing_ok)
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_OBJECT),
+					 errmsg("type \"%s\" does not exist",
+							TypeNameToString(typeName)),
+					 parser_errposition(pstate, typeName->location)));
+
+		return InvalidOid;
+	}
+
+	typoid = HeapTupleGetOid(tup);
+	ReleaseSysCache(tup);
+
+	return typoid;
+}
+
 /*
  * typenameType - given a TypeName, return a Type structure and typmod
  *
@@ -196,7 +244,7 @@ typenameType(ParseState *pstate, const TypeName *typeName, int32 *typmod_p)
 {
 	Type		tup;
 
-	tup = LookupTypeName(pstate, typeName, typmod_p);
+	tup = LookupTypeName(pstate, typeName, typmod_p, false);
 	if (tup == NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_UNDEFINED_OBJECT),

src/backend/utils/adt/regproc.c

@@ -135,7 +135,7 @@ regprocin(PG_FUNCTION_ARGS)
 	 * pg_proc entries in the current search path.
 	 */
 	names = stringToQualifiedNameList(pro_name_or_oid);
-	clist = FuncnameGetCandidates(names, -1, NIL, false, false);
+	clist = FuncnameGetCandidates(names, -1, NIL, false, false, false);
 
 	if (clist == NULL)
 		ereport(ERROR,
@@ -192,7 +192,7 @@ regprocout(PG_FUNCTION_ARGS)
 			 * qualify it.
 			 */
 			clist = FuncnameGetCandidates(list_make1(makeString(proname)),
-										  -1, NIL, false, false);
+										  -1, NIL, false, false, false);
 			if (clist != NULL && clist->next == NULL &&
 				clist->oid == proid)
 				nspname = NULL;
@@ -279,7 +279,7 @@ regprocedurein(PG_FUNCTION_ARGS)
 	 */
 	parseNameAndArgTypes(pro_name_or_oid, false, &names, &nargs, argtypes);
 
-	clist = FuncnameGetCandidates(names, nargs, NIL, false, false);
+	clist = FuncnameGetCandidates(names, nargs, NIL, false, false, false);
 
 	for (; clist; clist = clist->next)
 	{

src/include/catalog/namespace.h

@@ -71,7 +71,8 @@ extern bool TypeIsVisible(Oid typid);
 extern FuncCandidateList FuncnameGetCandidates(List *names,
 					  int nargs, List *argnames,
 					  bool expand_variadic,
-					  bool expand_defaults);
+					  bool expand_defaults,
+					  bool missing_ok);
 extern bool FunctionIsVisible(Oid funcid);
 
 extern Oid	OpernameGetOprid(List *names, Oid oprleft, Oid oprright);

src/include/parser/parse_type.h

@@ -20,7 +20,9 @@
 typedef HeapTuple Type;
 
 extern Type LookupTypeName(ParseState *pstate, const TypeName *typeName,
-			   int32 *typmod_p);
+			   int32 *typmod_p, bool missing_ok);
+extern Oid LookupTypeNameOid(ParseState *pstate, const TypeName *typeName,
+				  bool missing_ok);
 extern Type typenameType(ParseState *pstate, const TypeName *typeName,
 			 int32 *typmod_p);
 extern Oid	typenameTypeId(ParseState *pstate, const TypeName *typeName);

src/pl/plpgsql/src/pl_comp.c

@@ -1665,7 +1665,7 @@ plpgsql_parse_wordtype(char *ident)
 	 * Word wasn't found in the namespace stack. Try to find a data type with
 	 * that name, but ignore shell types and complex types.
 	 */
-	typeTup = LookupTypeName(NULL, makeTypeName(ident), NULL);
+	typeTup = LookupTypeName(NULL, makeTypeName(ident), NULL, false);
 	if (typeTup)
 	{
 		Form_pg_type typeStruct = (Form_pg_type) GETSTRUCT(typeTup);

src/test/regress/expected/drop_if_exists.out

@@ -169,11 +169,15 @@ NOTICE:  cast from type text to type text does not exist, skipping
 DROP TRIGGER test_trigger_exists ON test_exists;
 ERROR:  trigger "test_trigger_exists" for table "test_exists" does not exist
 DROP TRIGGER IF EXISTS test_trigger_exists ON test_exists;
-NOTICE:  trigger "test_trigger_exists" for table "test_exists" does not exist, skipping
+NOTICE:  trigger "test_trigger_exists" for relation "test_exists" does not exist, skipping
 DROP TRIGGER test_trigger_exists ON no_such_table;
 ERROR:  relation "no_such_table" does not exist
 DROP TRIGGER IF EXISTS test_trigger_exists ON no_such_table;
-ERROR:  relation "no_such_table" does not exist
+NOTICE:  relation "no_such_table" does not exist, skipping
+DROP TRIGGER test_trigger_exists ON no_such_schema.no_such_table;
+ERROR:  schema "no_such_schema" does not exist
+DROP TRIGGER IF EXISTS test_trigger_exists ON no_such_schema.no_such_table;
+NOTICE:  schema "no_such_schema" does not exist, skipping
 CREATE TRIGGER test_trigger_exists
     BEFORE UPDATE ON test_exists
     FOR EACH ROW EXECUTE PROCEDURE suppress_redundant_updates_trigger();
@@ -186,7 +190,11 @@ NOTICE:  rule "test_rule_exists" for relation "test_exists" does not exist, skip
 DROP RULE test_rule_exists ON no_such_table;
 ERROR:  relation "no_such_table" does not exist
 DROP RULE IF EXISTS test_rule_exists ON no_such_table;
-ERROR:  relation "no_such_table" does not exist
+NOTICE:  relation "no_such_table" does not exist, skipping
+DROP RULE test_rule_exists ON no_such_schema.no_such_table;
+ERROR:  schema "no_such_schema" does not exist
+DROP RULE IF EXISTS test_rule_exists ON no_such_schema.no_such_table;
+NOTICE:  schema "no_such_schema" does not exist, skipping
 CREATE RULE test_rule_exists AS ON INSERT TO test_exists
     DO INSTEAD
     INSERT INTO test_exists VALUES (NEW.a, NEW.b || NEW.a::text);
@@ -223,3 +231,68 @@ ERROR:  access method "no_such_am" does not exist
 DROP TABLE IF EXISTS test_exists;
 DROP TABLE test_exists;
 ERROR:  table "test_exists" does not exist
+-- be tolerant with missing schemas, types, etc
+DROP AGGREGATE IF EXISTS no_such_schema.foo(int);
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP AGGREGATE IF EXISTS foo(no_such_type);
+NOTICE:  type "no_such_type" does not exist, skipping
+DROP AGGREGATE IF EXISTS foo(no_such_schema.no_such_type);
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP CAST IF EXISTS (INTEGER AS no_such_type2);
+NOTICE:  type "no_such_type2" does not exist, skipping
+DROP CAST IF EXISTS (no_such_type1 AS INTEGER);
+NOTICE:  type "no_such_type1" does not exist, skipping
+DROP CAST IF EXISTS (INTEGER AS no_such_schema.bar);
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP CAST IF EXISTS (no_such_schema.foo AS INTEGER);
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP COLLATION IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP CONVERSION IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP DOMAIN IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP FOREIGN TABLE IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP FUNCTION IF EXISTS no_such_schema.foo();
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP FUNCTION IF EXISTS foo(no_such_type);
+NOTICE:  type "no_such_type" does not exist, skipping
+DROP FUNCTION IF EXISTS foo(no_such_schema.no_such_type);
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP INDEX IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP MATERIALIZED VIEW IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP OPERATOR IF EXISTS no_such_schema.+ (int, int);
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP OPERATOR IF EXISTS + (no_such_type, no_such_type);
+NOTICE:  type "no_such_type" does not exist, skipping
+DROP OPERATOR IF EXISTS + (no_such_schema.no_such_type, no_such_schema.no_such_type);
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP OPERATOR IF EXISTS # (NONE, no_such_schema.no_such_type);
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP OPERATOR CLASS IF EXISTS no_such_schema.widget_ops USING btree;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP OPERATOR FAMILY IF EXISTS no_such_schema.float_ops USING btree;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP RULE IF EXISTS foo ON no_such_schema.bar;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP SEQUENCE IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP TABLE IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP TEXT SEARCH CONFIGURATION IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP TEXT SEARCH DICTIONARY IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP TEXT SEARCH PARSER IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP TEXT SEARCH TEMPLATE IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP TRIGGER IF EXISTS foo ON no_such_schema.bar;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP TYPE IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping
+DROP VIEW IF EXISTS no_such_schema.foo;
+NOTICE:  schema "no_such_schema" does not exist, skipping

src/test/regress/expected/event_trigger.out

@@ -280,7 +280,7 @@ SELECT * FROM dropped_objects WHERE schema IS NULL OR schema <> 'pg_toast';
 (23 rows)
 
 DROP OWNED BY regression_bob;
-NOTICE:  table "audit_tbls_schema_one_table_two" does not exist, skipping
+NOTICE:  schema "audit_tbls" does not exist, skipping
 CONTEXT:  SQL statement "DROP TABLE IF EXISTS audit_tbls.audit_tbls_schema_one_table_two"
 PL/pgSQL function test_evtrig_dropped_objects() line 8 at EXECUTE statement
 SELECT * FROM dropped_objects WHERE type = 'schema';

src/test/regress/sql/drop_if_exists.sql

@@ -182,6 +182,9 @@ DROP TRIGGER IF EXISTS test_trigger_exists ON test_exists;
 DROP TRIGGER test_trigger_exists ON no_such_table;
 DROP TRIGGER IF EXISTS test_trigger_exists ON no_such_table;
 
+DROP TRIGGER test_trigger_exists ON no_such_schema.no_such_table;
+DROP TRIGGER IF EXISTS test_trigger_exists ON no_such_schema.no_such_table;
+
 CREATE TRIGGER test_trigger_exists
     BEFORE UPDATE ON test_exists
     FOR EACH ROW EXECUTE PROCEDURE suppress_redundant_updates_trigger();
@@ -194,6 +197,9 @@ DROP RULE IF EXISTS test_rule_exists ON test_exists;
 DROP RULE test_rule_exists ON no_such_table;
 DROP RULE IF EXISTS test_rule_exists ON no_such_table;
 
+DROP RULE test_rule_exists ON no_such_schema.no_such_table;
+DROP RULE IF EXISTS test_rule_exists ON no_such_schema.no_such_table;
+
 CREATE RULE test_rule_exists AS ON INSERT TO test_exists
     DO INSTEAD
     INSERT INTO test_exists VALUES (NEW.a, NEW.b || NEW.a::text);
@@ -226,3 +232,38 @@ DROP OPERATOR FAMILY IF EXISTS test_operator_family USING no_such_am;
 DROP TABLE IF EXISTS test_exists;
 
 DROP TABLE test_exists;
+
+-- be tolerant with missing schemas, types, etc
+
+DROP AGGREGATE IF EXISTS no_such_schema.foo(int);
+DROP AGGREGATE IF EXISTS foo(no_such_type);
+DROP AGGREGATE IF EXISTS foo(no_such_schema.no_such_type);
+DROP CAST IF EXISTS (INTEGER AS no_such_type2);
+DROP CAST IF EXISTS (no_such_type1 AS INTEGER);
+DROP CAST IF EXISTS (INTEGER AS no_such_schema.bar);
+DROP CAST IF EXISTS (no_such_schema.foo AS INTEGER);
+DROP COLLATION IF EXISTS no_such_schema.foo;
+DROP CONVERSION IF EXISTS no_such_schema.foo;
+DROP DOMAIN IF EXISTS no_such_schema.foo;
+DROP FOREIGN TABLE IF EXISTS no_such_schema.foo;
+DROP FUNCTION IF EXISTS no_such_schema.foo();
+DROP FUNCTION IF EXISTS foo(no_such_type);
+DROP FUNCTION IF EXISTS foo(no_such_schema.no_such_type);
+DROP INDEX IF EXISTS no_such_schema.foo;
+DROP MATERIALIZED VIEW IF EXISTS no_such_schema.foo;
+DROP OPERATOR IF EXISTS no_such_schema.+ (int, int);
+DROP OPERATOR IF EXISTS + (no_such_type, no_such_type);
+DROP OPERATOR IF EXISTS + (no_such_schema.no_such_type, no_such_schema.no_such_type);
+DROP OPERATOR IF EXISTS # (NONE, no_such_schema.no_such_type);
+DROP OPERATOR CLASS IF EXISTS no_such_schema.widget_ops USING btree;
+DROP OPERATOR FAMILY IF EXISTS no_such_schema.float_ops USING btree;
+DROP RULE IF EXISTS foo ON no_such_schema.bar;
+DROP SEQUENCE IF EXISTS no_such_schema.foo;
+DROP TABLE IF EXISTS no_such_schema.foo;
+DROP TEXT SEARCH CONFIGURATION IF EXISTS no_such_schema.foo;
+DROP TEXT SEARCH DICTIONARY IF EXISTS no_such_schema.foo;
+DROP TEXT SEARCH PARSER IF EXISTS no_such_schema.foo;
+DROP TEXT SEARCH TEMPLATE IF EXISTS no_such_schema.foo;
+DROP TRIGGER IF EXISTS foo ON no_such_schema.bar;
+DROP TYPE IF EXISTS no_such_schema.foo;
+DROP VIEW IF EXISTS no_such_schema.foo;