[CASSANDRA-17190] Add support for String contatenation through the "+" operator

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.1-alpha1, 4.1
• Component/s: CQL/Interpreter
• Labels: AdventCalendar2021 lhf
• Change Category: Semantic
• Complexity: Low Hanging Fruit
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/5cf62c6c02322505db9260d2aa9031386326fc75

Test and Documentation Plan

The PR add new unit tests

• Assignee: Manish Ghildiyal
• Reporter: Benjamin Lerer

Authors

Manish Ghildiyal

Reviewers

Benjamin Lerer, Berenguer Blasi, Brandon Williams

• Created: 06/Dec/21 14:07
• Updated: 27/May/22 19:25
• Resolved: 11/Feb/22 14:48

Description

Since 4.0, Cassandra support operations on numeric types and on some temporal types.
We should add support for string concatenations through the + operator.

Additional information for newcomers:

Cassandra has 2 string types: Text (UTF8Type) and ascii (AsciiType) both are sub-classes of (StringType). In order to add support for string concatenation you will need to add a new method to StringType and modify OperationFcts to add the new functions (one for each combination of types: ascii/ascii, ascii/text, text/ascii and text/text).

The unit test should be added to OperationFctsTest.
To allow for concatenating constants (eg: SELECT v1 + ' ' + v2 FROM ...) you will need to add a getPreferedTypeFor method to org.apache.cassandra.Constants.Type.STRING that determine the constant type based on its content (ascii or not).

Issue Links

• is a parent of: CASSANDRA-17383 Fix user_functions_test.py::TestUserFunctions::test_udf_overload