postgres.git / summary / log / commit / refs

commit    871dd024a6adf7766702b1cdacfb02bd8002d2bb
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Tue Nov 29 00:12:17 2011 +0000
First released in: 9.2.0, 9.1.2

    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(+)

diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index c334ca9cf8c..7192c458e75 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -1577,6 +1577,23 @@ 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],


[parent: 269755ef725a]