From ec3e183ec51bb2d4032be6d5402ddc7b4c8acb71 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 28 Nov 2011 19:12:17 -0500 Subject: Disallow deletion of CurrentExtensionObject while running extension script. While the deletion in itself wouldn't break things, any further creation of objects in the script would result in dangling pg_depend entries being added by recordDependencyOnCurrentExtension(). An example from Phil Sorber convinced me that this is just barely likely enough to be worth expending a couple lines of code to defend against. The resulting error message might be confusing, but it's better than leaving corrupted catalog contents for the user to deal with. --- src/backend/commands/extension.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'src/backend/commands') diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c index 024d4c8a00..63b3ffa4ef 100644 --- a/src/backend/commands/extension.c +++ b/src/backend/commands/extension.c @@ -1642,6 +1642,23 @@ RemoveExtensionById(Oid extId) HeapTuple tuple; ScanKeyData entry[1]; + /* + * Disallow deletion of any extension that's currently open for insertion; + * else subsequent executions of recordDependencyOnCurrentExtension() + * could create dangling pg_depend records that refer to a no-longer-valid + * pg_extension OID. This is needed not so much because we think people + * might write "DROP EXTENSION foo" in foo's own script files, as because + * errors in dependency management in extension script files could give + * rise to cases where an extension is dropped as a result of recursing + * from some contained object. Because of that, we must test for the case + * here, not at some higher level of the DROP EXTENSION command. + */ + if (extId == CurrentExtensionObject) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("cannot drop extension \"%s\" because it is being modified", + get_extension_name(extId)))); + rel = heap_open(ExtensionRelationId, RowExclusiveLock); ScanKeyInit(&entry[0], -- cgit v1.2.1