[CASSANDRA-17919] Capital P gets confused in the parser for a Duration in places where IDENT are needed

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 3.11.15, 4.0.10, 4.1.2, 5.0-alpha1, 5.0
• Component/s: CQL/Syntax
• Bug Category: Correctness - API / Semantic Definition
• Severity: Normal
• Complexity: Low Hanging Fruit
• Discovered By: Fuzz Test
• Platform: All
• Since Version: 3.10

Source Control Link

https://github.com/apache/cassandra/commit/0f3a990dd2bc9532752a711a49a131c63d52e3c7

Test and Documentation Plan

Pull requests

• cassandra-3.11 - https://github.com/apache/cassandra/pull/1977
• cassandra-4.0 - https://github.com/apache/cassandra/pull/1975
• cassandra-4.1 - https://github.com/apache/cassandra/pull/1976
• trunk - https://github.com/apache/cassandra/pull/2283

Source code changes
There was a change in the Lexer.g.
Capital letter "P" is no longer a valid representation for 0 duration. It has to comply with https://en.wikipedia.org/wiki/ISO_8601#Durations (see Benjamin Lerer's comment).
A couple of examples for valid 0 duration representation are:

PT0S
P0D
PT0H
P0W
P0Y0M0DT0H0M0S

Unit tests changes
The following tests have been expanded with new logic to cover the ticket's changes:

• org.apache.cassandra.cql3.validation.operations.CreateTest
• org.apache.cassandra.cql3.validation.operations.DropTest
• org.apache.cassandra.cql3.validation.operations.InsertTest

Manual test case flow
Let's go through the case where we create a "P" keyspace, use it, create a "P" table and insert 0 duration twice with the correct format (the updated), select all rows, try to insert 0 duration with incorrect format, get the error and lastly drop the "P" keyspace.

cqlsh> CREATE KEYSPACE IF NOT EXISTS P WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '1'};

cqlsh> USE P;

cqlsh:p> CREATE TABLE P (a INT PRIMARY KEY, b DURATION);

cqlsh:p> INSERT INTO P (a, b) VALUES (1, PT0S);
cqlsh:p> INSERT INTO P (a, b) VALUES (2, P0D);

cqlsh:p> SELECT * FROM P;

 a | b
---+---
 1 |  
 2 |  

(2 rows)

cqlsh:p> INSERT INTO P (a, b) VALUES (3, P);
SyntaxException: line 1:33 no viable alternative at input ')' (... b) VALUES (3, [P])...)

cqlsh:p> DROP KEYSPACE P;

cqlsh:p> describe keyspaces;

system       system_distributed  system_traces  system_virtual_schema
system_auth  system_schema       system_views 

• Assignee: Maxim Chanturiay
• Reporter: David Capwell

Authors

Maxim Chanturiay

Reviewers

Benjamin Lerer, Stefan Miklosovic

• Tester: Stefan Miklosovic
• Created: 23/Sep/22 18:05
• Updated: 12/Sep/23 13:02
• Resolved: 27/Apr/23 08:17

Description

This was found while adding Accord Transaction syntax into CQL and fuzz testing to validate all possible cases… in doing this the following was found

String query = "BEGIN TRANSACTION\n" +
                           "  LET P = (SELECT v FROM " + keyspace + ".tbl WHERE k=? AND c=?);\n" +
                           "  LET row2 = (SELECT v FROM " + keyspace + ".tbl WHERE k=? AND c=?);\n" +
                           "  SELECT v FROM " + keyspace + ".tbl WHERE k=? AND c=?;\n" +
                           "  IF P IS NULL AND row2.v = ? THEN\n" +
                           "    INSERT INTO " + keyspace + ".tbl (k, c, v) VALUES (?, ?, ?);\n" +
                           "  END IF\n" +
                           "COMMIT TRANSACTION";

Fails with

SyntaxException: line 2:6 mismatched input 'P' expecting IDENT (BEGIN TRANSACTION  LET [P]...)

The new LET syntax found this, but was able to reproduce in other cases

cqlsh:ks> CREATE TABLE P (k INT PRIMARY KEY);
SyntaxException: line 1:13 no viable alternative at input 'P' (CREATE TABLE [P]...)
cqlsh:ks>
cqlsh:ks> CREATE TABLE p (k INT PRIMARY KEY);
cqlsh:ks>

Issue Links

• links to: GitHub Pull Request #1975
• links to: GitHub Pull Request #1976
• links to: GitHub Pull Request #1977
• links to: GitHub Pull Request #2283