MultipartResponseParsing.DataLineIterator.next() produces infinite loop in some cases

[frehulfd]

Summary

In certain configurations during multipart body message passing, in this case a subscription, if a new chunk only has one CRLF at the end, the DataLineIterator will return the same DataLine forever.

Relevant Source:

apollo-ios/Sources/Apollo/ResponseParsing/MultipartResponseSpecificationParser.swift

Lines 46 to 48 in 1025aa9

	guard let separatorRange = data.firstRange(of: Self.DataLineSeparator) else {
	return data
	}

Version

2.0.2

Steps to reproduce the behavior

Example stream:

--graphql
content-type: application/json

{}
--graphql
content-type: application/json

{"payload":{"data":{"conversationNewMessage":{"__typename":"ConversationNewMessagePayload","message":{"__typename":"ConversationMessage","text":"This is a Test122","conversationId":"don-chat-id"}}},"extensions":{"cost":{"config-graphql-api":{"actualQueryCost":1,"maxQueryCost":200,"requestedQueryCost":6}}}}}
--graphql
content-type: application/json

{}
--graphql
content-type: application/json

{}
--graphql
content-type: application/json

{}
--graphql
content-type: application/json

{"payload":{"data":null,"errors":[{"message":"the connection has been closed because it hasn't heartbeat for a while","extensions":{"code":"SUBSCRIPTION_HEARTBEAT_ERROR"}}],"extensions":{"cost":{"config-graphql-api":{"actualQueryCost":1,"maxQueryCost":200,"requestedQueryCost":6}}}}}
--graphql--

Parsing will loop infinitely on the first heartbeat.

Should probably be something like:

guard let separatorRange = data.firstRange(of: Self.DataLineSeparator) else {
    let fullData = data
    data = Data()
    return fullData
}

Logs

Anything else?

No response

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[AnthonyMDev]

Fixed in 2.0.3. Thanks for the bug report @frehulfd!