Refactor the handling of the various DropStmt variants so that when multiple

objects are specified, we drop them all in a single performMultipleDeletions
call.  This makes the RESTRICT/CASCADE checks more relaxed: it's not counted
as a cascade if one of the later objects has a dependency on an earlier one.
NOTICE messages about such cases go away, too.

In passing, fix the permissions check for DROP CONVERSION, which for some
reason was never made role-aware, and omitted the namespace-owner exemption
too.

Alex Hunsaker, with further fiddling by me.

Author: tglsfdc

src/backend/catalog/dependency.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/dependency.c,v 1.75 2008/06/11 21:53:48 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/dependency.c,v 1.76 2008/06/14 18:04:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -259,6 +259,10 @@ performMultipleDeletions(const ObjectAddresses *objects,
 	ObjectAddresses *targetObjects;
 	int			i;
 
+	/* No work if no objects... */
+	if (objects->numrefs <= 0)
+		return;
+
 	/*
 	 * We save some cycles by opening pg_depend just once and passing the
 	 * Relation pointer down to all the recursive deletion steps.
@@ -295,11 +299,14 @@ performMultipleDeletions(const ObjectAddresses *objects,
 
 	/*
 	 * Check if deletion is allowed, and report about cascaded deletes.
+	 *
+	 * If there's exactly one object being deleted, report it the same
+	 * way as in performDeletion(), else we have to be vaguer.
 	 */
 	reportDependentObjects(targetObjects,
 						   behavior,
 						   NOTICE,
-						   NULL);
+						   (objects->numrefs == 1 ? objects->refs : NULL));
 
 	/*
 	 * Delete all the objects in the proper order.

src/backend/catalog/pg_conversion.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/pg_conversion.c,v 1.43 2008/05/12 00:00:47 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/pg_conversion.c,v 1.44 2008/06/14 18:04:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,7 +18,6 @@
 #include "access/sysattr.h"
 #include "catalog/dependency.h"
 #include "catalog/indexing.h"
-#include "catalog/namespace.h"
 #include "catalog/pg_conversion.h"
 #include "catalog/pg_conversion_fn.h"
 #include "catalog/pg_namespace.h"
@@ -138,40 +137,6 @@ ConversionCreate(const char *conname, Oid connamespace,
 	return oid;
 }
 
-/*
- * ConversionDrop
- *
- * Drop a conversion after doing permission checks.
- */
-void
-ConversionDrop(Oid conversionOid, DropBehavior behavior)
-{
-	HeapTuple	tuple;
-	ObjectAddress object;
-
-	tuple = SearchSysCache(CONVOID,
-						   ObjectIdGetDatum(conversionOid),
-						   0, 0, 0);
-	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "cache lookup failed for conversion %u", conversionOid);
-
-	if (!superuser() &&
-		((Form_pg_conversion) GETSTRUCT(tuple))->conowner != GetUserId())
-		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CONVERSION,
-				  NameStr(((Form_pg_conversion) GETSTRUCT(tuple))->conname));
-
-	ReleaseSysCache(tuple);
-
-	/*
-	 * Do the deletion
-	 */
-	object.classId = ConversionRelationId;
-	object.objectId = conversionOid;
-	object.objectSubId = 0;
-
-	performDeletion(&object, behavior);
-}
-
 /*
  * RemoveConversionById
  *

src/backend/commands/conversioncmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/conversioncmds.c,v 1.33 2008/03/27 03:57:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/conversioncmds.c,v 1.34 2008/06/14 18:04:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -99,31 +99,73 @@ CreateConversionCommand(CreateConversionStmt *stmt)
  * DROP CONVERSION
  */
 void
-DropConversionCommand(List *name, DropBehavior behavior, bool missing_ok)
+DropConversionsCommand(DropStmt *drop)
 {
-	Oid			conversionOid;
+	ObjectAddresses *objects;
+	ListCell *cell;
 
-	conversionOid = FindConversionByName(name);
-	if (!OidIsValid(conversionOid))
+	/*
+	 * First we identify all the conversions, then we delete them in a single
+	 * performMultipleDeletions() call.  This is to avoid unwanted
+	 * DROP RESTRICT errors if one of the conversions depends on another.
+	 * (Not that that is very likely, but we may as well do this consistently.)
+	 */
+	objects = new_object_addresses();
+
+	foreach(cell, drop->objects)
 	{
-		if (!missing_ok)
-		{
-			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_OBJECT),
-					 errmsg("conversion \"%s\" does not exist",
-							NameListToString(name))));
-		}
-		else
+		List		*name = (List *) lfirst(cell);
+		Oid			conversionOid;
+		HeapTuple	tuple;
+		Form_pg_conversion con;
+		ObjectAddress object;
+
+		conversionOid = FindConversionByName(name);
+
+		if (!OidIsValid(conversionOid))
 		{
-			ereport(NOTICE,
-					(errmsg("conversion \"%s\" does not exist, skipping",
-							NameListToString(name))));
+			if (!drop->missing_ok)
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_OBJECT),
+						 errmsg("conversion \"%s\" does not exist",
+								NameListToString(name))));
+			}
+			else
+			{
+				ereport(NOTICE,
+						(errmsg("conversion \"%s\" does not exist, skipping",
+								NameListToString(name))));
+			}
+			continue;
 		}
 
-		return;
+		tuple = SearchSysCache(CONVOID,
+							   ObjectIdGetDatum(conversionOid),
+							   0, 0, 0);
+		if (!HeapTupleIsValid(tuple))
+			elog(ERROR, "cache lookup failed for conversion %u",
+				 conversionOid);
+		con = (Form_pg_conversion) GETSTRUCT(tuple);
+
+		/* Permission check: must own conversion or its namespace */
+		if (!pg_conversion_ownercheck(conversionOid, GetUserId()) &&
+			!pg_namespace_ownercheck(con->connamespace, GetUserId()))
+			aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CONVERSION,
+						   NameStr(con->conname));
+
+		object.classId = ConversionRelationId;
+		object.objectId = conversionOid;
+		object.objectSubId = 0;
+
+		add_exact_object_address(&object, objects);
+
+		ReleaseSysCache(tuple);
 	}
 
-	ConversionDrop(conversionOid, behavior);
+	performMultipleDeletions(objects, drop->behavior);
+
+	free_object_addresses(objects);
 }
 
 /*

src/backend/commands/indexcmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.176 2008/05/12 20:01:59 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.177 2008/06/14 18:04:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -21,7 +21,6 @@
 #include "access/transam.h"
 #include "access/xact.h"
 #include "catalog/catalog.h"
-#include "catalog/dependency.h"
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
@@ -1256,33 +1255,6 @@ relationHasPrimaryKey(Relation rel)
 	return result;
 }
 
-
-/*
- * RemoveIndex
- *		Deletes an index.
- */
-void
-RemoveIndex(RangeVar *relation, DropBehavior behavior)
-{
-	Oid			indOid;
-	char		relkind;
-	ObjectAddress object;
-
-	indOid = RangeVarGetRelid(relation, false);
-	relkind = get_rel_relkind(indOid);
-	if (relkind != RELKIND_INDEX)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not an index",
-						relation->relname)));
-
-	object.classId = RelationRelationId;
-	object.objectId = indOid;
-	object.objectSubId = 0;
-
-	performDeletion(&object, behavior);
-}
-
 /*
  * ReindexIndex
  *		Recreate a specific index.

src/backend/commands/schemacmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/schemacmds.c,v 1.49 2008/01/03 21:23:15 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/schemacmds.c,v 1.50 2008/06/14 18:04:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -148,57 +148,76 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
 
 
 /*
- *	RemoveSchema
- *		Removes a schema.
+ *	RemoveSchemas
+ *		Implements DROP SCHEMA.
  */
 void
-RemoveSchema(List *names, DropBehavior behavior, bool missing_ok)
+RemoveSchemas(DropStmt *drop)
 {
-	char	   *namespaceName;
-	Oid			namespaceId;
-	ObjectAddress object;
+	ObjectAddresses *objects;
+	ListCell		*cell;
 
-	if (list_length(names) != 1)
-		ereport(ERROR,
-				(errcode(ERRCODE_SYNTAX_ERROR),
-				 errmsg("schema name cannot be qualified")));
-	namespaceName = strVal(linitial(names));
-
-	namespaceId = GetSysCacheOid(NAMESPACENAME,
-								 CStringGetDatum(namespaceName),
-								 0, 0, 0);
-	if (!OidIsValid(namespaceId))
+	/*
+	 * First we identify all the schemas, then we delete them in a single
+	 * performMultipleDeletions() call.  This is to avoid unwanted
+	 * DROP RESTRICT errors if one of the schemas depends on another.
+	 */
+	objects = new_object_addresses();
+
+	foreach(cell, drop->objects)
 	{
-		if (!missing_ok)
-		{
+		List	   *names = (List *) lfirst(cell);
+		char	   *namespaceName;
+		Oid			namespaceId;
+		ObjectAddress object;
+
+		if (list_length(names) != 1)
 			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_SCHEMA),
-					 errmsg("schema \"%s\" does not exist", namespaceName)));
-		}
-		else
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("schema name cannot be qualified")));
+		namespaceName = strVal(linitial(names));
+
+		namespaceId = GetSysCacheOid(NAMESPACENAME,
+									 CStringGetDatum(namespaceName),
+									 0, 0, 0);
+
+		if (!OidIsValid(namespaceId))
 		{
-			ereport(NOTICE,
-					(errmsg("schema \"%s\" does not exist, skipping",
-							namespaceName)));
+			if (!drop->missing_ok)
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_SCHEMA),
+						 errmsg("schema \"%s\" does not exist",
+								namespaceName)));
+			}
+			else
+			{
+				ereport(NOTICE,
+						(errmsg("schema \"%s\" does not exist, skipping",
+								namespaceName)));
+			}
+			continue;
 		}
 
-		return;
-	}
+		/* Permission check */
+		if (!pg_namespace_ownercheck(namespaceId, GetUserId()))
+			aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_NAMESPACE,
+						   namespaceName);
 
-	/* Permission check */
-	if (!pg_namespace_ownercheck(namespaceId, GetUserId()))
-		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_NAMESPACE,
-					   namespaceName);
+		object.classId = NamespaceRelationId;
+		object.objectId = namespaceId;
+		object.objectSubId = 0;
+
+		add_exact_object_address(&object, objects);
+	}
 
 	/*
-	 * Do the deletion.  Objects contained in the schema are removed by means
-	 * of their dependency links to the schema.
+	 * Do the deletions.  Objects contained in the schema(s) are removed by
+	 * means of their dependency links to the schema.
 	 */
-	object.classId = NamespaceRelationId;
-	object.objectId = namespaceId;
-	object.objectSubId = 0;
+	performMultipleDeletions(objects, drop->behavior);
 
-	performDeletion(&object, behavior);
+	free_object_addresses(objects);
 }