Dynamodb KeyConditionExpression use gives ValidationException

[joe94]

Confirm by changing [ ] to [x] below to ensure that it's a bug:

• I've gone through Developer Guide and API reference
• I've checked AWS Forums and StackOverflow for answers
• I've searched for previous similar issues and didn't find any solution

Describe the bug
Error Seen migrating Query() calls from KeyConditions to KeyConditionExpressions

Version of AWS SDK for Go?
1.34.19

Version of Go (go version)?
go1.14.3

To Reproduce (observed behavior)
This is the original code fragment that works fine:

	queryResult, err := d.c.Query(&dynamodb.QueryInput{
		TableName: aws.String(d.tableName),
		KeyConditions: map[string]*dynamodb.Condition{
			"bucket": {
				ComparisonOperator: aws.String("EQ"),
				AttributeValueList: []*dynamodb.AttributeValue{
					{
						S: &bucket,
					},
				},
			},
		},
		ReturnConsumedCapacity: aws.String(dynamodb.ReturnConsumedCapacityTotal),
	})

Then following the instructions here: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.KeyConditions.html

I wrote the following which at runtime throws a validationException.

	queryResult, err := d.c.Query(&dynamodb.QueryInput{
		TableName:              aws.String(d.tableName),
		KeyConditionExpression: aws.String("bucket = :b"),
		ExpressionAttributeValues: map[string]*dynamodb.AttributeValue{
			"b": {
				S: &bucket,
			},
		},
		ReturnConsumedCapacity: aws.String(dynamodb.ReturnConsumedCapacityTotal),
	})

Expected behavior
I wanted the behavior to match that of the legacy functions.

Additional context
bucket is a partitionKey.

[kevinmichaelchen]

I was getting a similar ValidationException with expression.NewBuilder. Ultimately, what was causing the error on my end was using the QueryInput.IndexName field (not sure why).

Here's what worked for me:

cond, err := expression.NewBuilder().
	WithKeyCondition(expression.Key("bucket").Equal(expression.Value(bucket))).
	Build()

// handle error

q := dynamodb.QueryInput{
	TableName: aws.String("my-buckets-table"),
	// TODO this line is problematic, since we get the error:
	//  failed to query data: ValidationException: The table does not have the specified index: bucket
	//IndexName:                 aws.String("bucket"),
	KeyConditionExpression:    cond.KeyCondition(),
	ExpressionAttributeNames:  cond.Names(),
	ExpressionAttributeValues: cond.Values(),
	Limit:                     aws.Int64(1),
}