SqlNullabilityProcessor and COALESCE with more than two arguments

[dmitry-lipetsk]

Hello,

efcore/src/EFCore.Relational/Query/SqlNullabilityProcessor.cs

Lines 1035 to 1045 in 59e9ff2

	if (sqlFunctionExpression.IsBuiltIn
	&& sqlFunctionExpression.Arguments != null
	&& string.Equals(sqlFunctionExpression.Name, "COALESCE", StringComparison.OrdinalIgnoreCase))
	{
	var left = Visit(sqlFunctionExpression.Arguments[0], out var leftNullable);
	var right = Visit(sqlFunctionExpression.Arguments[1], out var rightNullable);
	nullable = leftNullable && rightNullable;
	return sqlFunctionExpression.Update(sqlFunctionExpression.Instance, new[] { left, right });
	}

SQL-function COALESCE allows usage more than two parameters.

My provider, for example, may generate a call of COALESCE with many arguments.

I think, your generic SqlNullabilityProcessor must process all arguments of COALESCE. Not only [0] and [1].

[dmitry-lipetsk]

Same problem in next code:

efcore/src/EFCore.Relational/Query/SqlNullabilityProcessor.cs

Lines 1731 to 1761 in 59e9ff2

	if (sqlFunctionExpression.IsBuiltIn
	&& string.Equals("COALESCE", sqlFunctionExpression.Name, StringComparison.OrdinalIgnoreCase))
	{
	// for coalesce:
	// (a ?? b) == null -> a == null && b == null
	// (a ?? b) != null -> a != null || b != null
	var left = ProcessNullNotNull(
	_sqlExpressionFactory.MakeUnary(
	sqlUnaryExpression.OperatorType,
	sqlFunctionExpression.Arguments![0],
	typeof(bool),
	sqlUnaryExpression.TypeMapping)!,
	operandNullable);
	var right = ProcessNullNotNull(
	_sqlExpressionFactory.MakeUnary(
	sqlUnaryExpression.OperatorType,
	sqlFunctionExpression.Arguments[1],
	typeof(bool),
	sqlUnaryExpression.TypeMapping)!,
	operandNullable);
	return SimplifyLogicalSqlBinaryExpression(
	_sqlExpressionFactory.MakeBinary(
	sqlUnaryExpression.OperatorType == ExpressionType.Equal
	? ExpressionType.AndAlso
	: ExpressionType.OrElse,
	left,
	right,
	sqlUnaryExpression.TypeMapping)!);
	}