[CASSANDRA-18264] CustomClassLoader does not load jars rendering triggers from JARs broken

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.1.1, 5.0-alpha1, 5.0
• Component/s: Legacy/Core
• Bug Category: Code
• Severity: Normal
• Complexity: Low Hanging Fruit
• Discovered By: User Report
• Platform: All
• Since Version: 4.1-alpha1

Source Control Link

https://github.com/apache/cassandra/commit/9860c1e9d9fb45342fa674782ecd135cf6875943

Test and Documentation Plan

CI

• Assignee: Stefan Miklosovic
• Reporter: Stefan Miklosovic

Authors

Stefan Miklosovic

Reviewers

Brandon Williams

• Created: 15/Feb/23 21:22
• Updated: 12/Sep/23 13:02
• Resolved: 17/Feb/23 15:55

Description

A user had to downgrade to 4.0.7 from 4.1.0 because they hit a problem with CustomClassLoader for triggers.

User says that in Apache Cassandra 4.1.0 the trigger mechanism does not work, not their trigger, but the possibility of loading any trigger in Cassandra.

In the Cassandra 4.1.0 version of CustomClassLoader (https://github.com/apache/cassandra/blob/cassandra-4.1/src/java/org/apache/cassandra/triggers/CustomClassLoader.java) the code is changed in such a way that when copying the JAR Cassandra uses java.nio.file.Files, while earlier versions (cassandra 4.0.X or 3.X) used Guava com.google.common.io.Files to copy the JAR file.

The difference between one and the other is that Guava by default overwrites the file if it already exists and user has permissions to do so, and in Java by default it does not overwrite.

Copying is done here (1) from inputJar to out. However, the problem is that we are getting temporary file from here (2) and the implementation loops unless it succeeds to create an empty file. (3) - But that fails to copy the file to out because copying does not work when the target file already exists.

(1) https://github.com/apache/cassandra/blob/cassandra-4.1/src/java/org/apache/cassandra/triggers/CustomClassLoader.java#L86

(2) https://github.com/apache/cassandra/blob/cassandra-4.1/src/java/org/apache/cassandra/triggers/CustomClassLoader.java#L81

(3) https://github.com/apache/cassandra/blob/cassandra-4.1/src/java/org/apache/cassandra/io/util/FileUtils.java#L152

Issue Links

• Discovered while testing: CASSANDRA-18270 ssl-factory demo in examples is broken