[CALCITE-4795] In class SqlBasicCall, make the "operands" field private

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.29.0
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 23/Sep/21 06:00
• Updated: 04/Jan/22 08:27
• Resolved: 04/Jan/22 08:27

Description

In class SqlBasicCall, the operands field is a public array. This seems crazy to me – any client might be writing into that field at any time. I propose to make the field private.

This presents some compatibility problems, because people might be depending on the field. So I propose a quick deprecation and removal:

• In release 1.28 (the next release, as I write this) the field and the public SqlNode[] getOperands() method will be marked deprecated. We will mirror into another field, private final List<SqlNode> operandList = Arrays.asList(operands); We can replace all uses of the operands field in Calcite with uses of the new operandList field.
• In release 1.29 (the release after next) the operands field and the getOperands() method will be removed. People can operate using List<SqlNode> getOperandList() and setOperand(int, SqlNode) methods that are inherited from SqlCall.

After the field is a private list, we could consider making it an immutable list. The list would be copied when people call setOperand, but would not need to be cloned when the SqlBasicCall is created or cloned.

This case completes the work started in CALCITE-147.

Issue Links

• relates to: CALCITE-147 Convert SqlNode to interface