Further consolidation of DROP statement handling.

This gets rid of an impressive amount of duplicative code, with only
minimal behavior changes.  DROP FOREIGN DATA WRAPPER now requires object
ownership rather than superuser privileges, matching the documentation
we already have.  We also eliminate the historical warning about dropping
a built-in function as unuseful.  All operations are now performed in the
same order for all object types handled by dropcmds.c.

KaiGai Kohei, with minor revisions by me

Author: robertmhaas

src/backend/commands/aggregatecmds.c

@@ -208,58 +208,9 @@ DefineAggregate(List *name, List *args, bool oldstyle, List *parameters)
 
 
 /*
- * RemoveAggregate
- *		Deletes an aggregate.
+ * RenameAggregate
+ *		Rename an aggregate.
  */
-void
-RemoveAggregate(RemoveFuncStmt *stmt)
-{
-	List	   *aggName = stmt->name;
-	List	   *aggArgs = stmt->args;
-	Oid			procOid;
-	HeapTuple	tup;
-	ObjectAddress object;
-
-	/* Look up function and make sure it's an aggregate */
-	procOid = LookupAggNameTypeNames(aggName, aggArgs, stmt->missing_ok);
-
-	if (!OidIsValid(procOid))
-	{
-		/* we only get here if stmt->missing_ok is true */
-		ereport(NOTICE,
-				(errmsg("aggregate %s(%s) does not exist, skipping",
-						NameListToString(aggName),
-						TypeNameListToString(aggArgs))));
-		return;
-	}
-
-	/*
-	 * Find the function tuple, do permissions and validity checks
-	 */
-	tup = SearchSysCache1(PROCOID, ObjectIdGetDatum(procOid));
-	if (!HeapTupleIsValid(tup)) /* should not happen */
-		elog(ERROR, "cache lookup failed for function %u", procOid);
-
-	/* Permission check: must own agg or its namespace */
-	if (!pg_proc_ownercheck(procOid, GetUserId()) &&
-	  !pg_namespace_ownercheck(((Form_pg_proc) GETSTRUCT(tup))->pronamespace,
-							   GetUserId()))
-		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_PROC,
-					   NameListToString(aggName));
-
-	ReleaseSysCache(tup);
-
-	/*
-	 * Do the deletion
-	 */
-	object.classId = ProcedureRelationId;
-	object.objectId = procOid;
-	object.objectSubId = 0;
-
-	performDeletion(&object, stmt->behavior);
-}
-
-
 void
 RenameAggregate(List *name, List *args, const char *newname)
 {

src/backend/commands/dropcmds.c

@@ -20,13 +20,17 @@
 #include "catalog/namespace.h"
 #include "catalog/objectaddress.h"
 #include "catalog/pg_class.h"
+#include "catalog/pg_proc.h"
 #include "commands/defrem.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "parser/parse_type.h"
 #include "utils/acl.h"
+#include "utils/builtins.h"
+#include "utils/syscache.h"
 
-static void does_not_exist_skipping(ObjectType objtype, List *objname);
+static void does_not_exist_skipping(ObjectType objtype,
+									List *objname, List *objargs);
 
 /*
  * Drop one or more objects.
@@ -44,36 +48,68 @@ RemoveObjects(DropStmt *stmt)
 {
 	ObjectAddresses *objects;
 	ListCell   *cell1;
+	ListCell   *cell2 = NULL;
 
 	objects = new_object_addresses();
 
 	foreach(cell1, stmt->objects)
 	{
 		ObjectAddress	address;
 		List	   *objname = lfirst(cell1);
+		List	   *objargs = NIL;
 		Relation	relation = NULL;
 		Oid			namespaceId;
 
+		if (stmt->arguments)
+		{
+			cell2 = (!cell2 ? list_head(stmt->arguments) : lnext(cell2));
+			objargs = lfirst(cell2);
+		}
+
 		/* Get an ObjectAddress for the object. */
 		address = get_object_address(stmt->removeType,
-									 objname, NIL,
+									 objname, objargs,
 									 &relation,
 									 AccessExclusiveLock,
 									 stmt->missing_ok);
 
 		/* Issue NOTICE if supplied object was not found. */
 		if (!OidIsValid(address.objectId))
 		{
-			does_not_exist_skipping(stmt->removeType, objname);
+			does_not_exist_skipping(stmt->removeType, objname, objargs);
 			continue;
 		}
 
+		/*
+		 * Although COMMENT ON FUNCTION, SECURITY LABEL ON FUNCTION, etc. are
+		 * happy to operate on an aggregate as on any other function, we have
+		 * historically not allowed this for DROP FUNCTION.
+		 */
+		if (stmt->removeType == OBJECT_FUNCTION)
+		{
+			Oid			funcOid = address.objectId;
+			HeapTuple	tup;
+
+			tup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcOid));
+			if (!HeapTupleIsValid(tup)) /* should not happen */
+				elog(ERROR, "cache lookup failed for function %u", funcOid);
+
+			if (((Form_pg_proc) GETSTRUCT(tup))->proisagg)
+				ereport(ERROR,
+						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+								 errmsg("\"%s\" is an aggregate function",
+									NameListToString(objname)),
+				errhint("Use DROP AGGREGATE to drop aggregate functions.")));
+
+			ReleaseSysCache(tup);
+		}
+
 		/* Check permissions. */
 		namespaceId = get_object_namespace(&address);
 		if (!OidIsValid(namespaceId) ||
 			!pg_namespace_ownercheck(namespaceId, GetUserId()))
 			check_object_ownership(GetUserId(), stmt->removeType, address,
-								   objname, NIL, relation);
+								   objname, objargs, relation);
 
 		/* Release any relcache reference count, but keep lock until commit. */
 		if (relation)
@@ -94,10 +130,11 @@ RemoveObjects(DropStmt *stmt)
  * get_object_address() will throw an ERROR.
  */
 static void
-does_not_exist_skipping(ObjectType objtype, List *objname)
+does_not_exist_skipping(ObjectType objtype, List *objname, List *objargs)
 {
 	const char *msg = NULL;
 	char	   *name = NULL;
+	char	   *args = NULL;
 
 	switch (objtype)
 	{
@@ -138,10 +175,68 @@ does_not_exist_skipping(ObjectType objtype, List *objname)
 			msg = gettext_noop("extension \"%s\" does not exist, skipping");
 			name = NameListToString(objname);
 			break;
+		case OBJECT_FUNCTION:
+			msg = gettext_noop("function %s(%s) does not exist, skipping");
+			name = NameListToString(objname);
+			args = TypeNameListToString(objargs);
+			break;
+		case OBJECT_AGGREGATE:
+			msg = gettext_noop("aggregate %s(%s) does not exist, skipping");
+			name = NameListToString(objname);
+			args = TypeNameListToString(objargs);
+			break;
+		case OBJECT_OPERATOR:
+			msg = gettext_noop("operator %s does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_LANGUAGE:
+			msg = gettext_noop("language \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_CAST:
+			msg = gettext_noop("cast from type %s to type %s does not exist, skipping");
+			name = format_type_be(typenameTypeId(NULL,
+								  (TypeName *) linitial(objname)));
+			args = format_type_be(typenameTypeId(NULL,
+								  (TypeName *) linitial(objargs)));
+			break;
+		case OBJECT_TRIGGER:
+			msg = gettext_noop("trigger \"%s\" for table \"%s\" does not exist, skipping");
+			name = strVal(llast(objname));
+			args = NameListToString(list_truncate(objname,
+												  list_length(objname) - 1));
+			break;
+		case OBJECT_RULE:
+			msg = gettext_noop("rule \"%s\" for relation \"%s\" does not exist, skipping");
+			name = strVal(llast(objname));
+			args = NameListToString(list_truncate(objname,
+												  list_length(objname) - 1));
+			break;
+		case OBJECT_FDW:
+			msg = gettext_noop("foreign-data wrapper \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_FOREIGN_SERVER:
+			msg = gettext_noop("server \"%s\" does not exist, skipping");
+			name = NameListToString(objname);
+			break;
+		case OBJECT_OPCLASS:
+			msg = gettext_noop("operator class \"%s\" does not exist for access method \"%s\", skipping");
+			name = NameListToString(objname);
+			args = strVal(linitial(objargs));
+			break;
+		case OBJECT_OPFAMILY:
+			msg = gettext_noop("operator family \"%s\" does not exist for access method \"%s\", skipping");
+			name = NameListToString(objname);
+			args = strVal(linitial(objargs));
+			break;
 		default:
 			elog(ERROR, "unexpected object type (%d)", (int)objtype);
 			break;
 	}
 
-	ereport(NOTICE, (errmsg(msg, name)));
+	if (!args)
+		ereport(NOTICE, (errmsg(msg, name)));
+	else
+		ereport(NOTICE, (errmsg(msg, name, args)));
 }

src/backend/commands/foreigncmds.c

@@ -685,50 +685,6 @@ AlterForeignDataWrapper(AlterFdwStmt *stmt)
 }
 
 
-/*
- * Drop foreign-data wrapper
- */
-void
-RemoveForeignDataWrapper(DropFdwStmt *stmt)
-{
-	Oid			fdwId;
-	ObjectAddress object;
-
-	fdwId = get_foreign_data_wrapper_oid(stmt->fdwname, true);
-
-	if (!superuser())
-		ereport(ERROR,
-				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-			  errmsg("permission denied to drop foreign-data wrapper \"%s\"",
-					 stmt->fdwname),
-			  errhint("Must be superuser to drop a foreign-data wrapper.")));
-
-	if (!OidIsValid(fdwId))
-	{
-		if (!stmt->missing_ok)
-			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_OBJECT),
-					 errmsg("foreign-data wrapper \"%s\" does not exist",
-							stmt->fdwname)));
-
-		/* IF EXISTS specified, just note it */
-		ereport(NOTICE,
-			  (errmsg("foreign-data wrapper \"%s\" does not exist, skipping",
-					  stmt->fdwname)));
-		return;
-	}
-
-	/*
-	 * Do the deletion
-	 */
-	object.classId = ForeignDataWrapperRelationId;
-	object.objectId = fdwId;
-	object.objectSubId = 0;
-
-	performDeletion(&object, stmt->behavior);
-}
-
-
 /*
  * Drop foreign-data wrapper by OID
  */
@@ -957,45 +913,6 @@ AlterForeignServer(AlterForeignServerStmt *stmt)
 }
 
 
-/*
- * Drop foreign server
- */
-void
-RemoveForeignServer(DropForeignServerStmt *stmt)
-{
-	Oid			srvId;
-	ObjectAddress object;
-
-	srvId = get_foreign_server_oid(stmt->servername, true);
-
-	if (!OidIsValid(srvId))
-	{
-		/* Server not found, complain or notice */
-		if (!stmt->missing_ok)
-			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_OBJECT),
-				  errmsg("server \"%s\" does not exist", stmt->servername)));
-
-		/* IF EXISTS specified, just note it */
-		ereport(NOTICE,
-				(errmsg("server \"%s\" does not exist, skipping",
-						stmt->servername)));
-		return;
-	}
-
-	/* Only allow DROP if the server is owned by the user. */
-	if (!pg_foreign_server_ownercheck(srvId, GetUserId()))
-		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_FOREIGN_SERVER,
-					   stmt->servername);
-
-	object.classId = ForeignServerRelationId;
-	object.objectId = srvId;
-	object.objectSubId = 0;
-
-	performDeletion(&object, stmt->behavior);
-}
-
-
 /*
  * Drop foreign server by OID
  */