Affects Version/s: 7.3, 7.3.1
Fix Version/s: None
Security Level: Public (Default Security Level. Issues are Public)
Premise: During an upgrade I should be able to run a 7.3 pull replica against a 7.2 tlog leader. Or vice versa.
Adding a new method to SolrResponse has broken binary compatibility. When I try to register a new pull replica using the admin api I get an HTTP 500 responseI see this error logged: java.io.InvalidClassException: org.apache.solr.client.solrj.SolrResponse; local class incompatible: stream classdesc serialVersionUID = 3945300637328478755, local class serialVersionUID = -793110010336024264
The replica actually seems to register ok it just can't read the response because the bytes from the 7.2 leader include a different serialVersionUID.
Should SolrResponse include a serialVersionIUID? All subclasses too.
Mark Miller's advice is that the project should never use builtin java serialization.
It looks like stock java serialization is only used for these admin responses. Query responses use JavaBinCodec instead..
Full(ish) stack trace: