DynamoDB Enhanced Client - QueryConditional does not support reserved characters : and #

[dhegberg]

Describe the bug

The reserved characters : and # are not "scrubbed" from expression key/value mappers when the QueryConditional calls cleanAttributeName

Example QueryConditional:

aws-sdk-java-v2/services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/conditional/EqualToConditional.java

Lines 36 to 37 in 1a1eb6e

	private static final UnaryOperator<String> EXPRESSION_KEY_MAPPER =
	k -> "#AMZN_MAPPED_" + cleanAttributeName(k);

cleanAttributeName:

aws-sdk-java-v2/services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/EnhancedClientUtils.java

Lines 48 to 60 in 1a1eb6e

	public static String cleanAttributeName(String key) {
	boolean somethingChanged = false;
	char[] chars = key.toCharArray();
	for (int i = 0; i < chars.length; ++i) {
	if (chars[i] == '*' || chars[i] == '.' || chars[i] == '-') {
	chars[i] = '_';
	somethingChanged = true;
	}
	}
	return somethingChanged ? new String(chars) : key;
	}

Expected Behavior

Attribute names with : and # characters would be replaced with placeholders, allowing for successful query of table with those attribute names.

Current Behavior

The reserved characters are not replaced, resulting in a 400 due to "ExpressionAttributeNames contains invalid key" during query request.

[bmaizels]

Thanks for the bug report. Working on a fix.