SOLR-17263: HttpJdkSolrClient doesn't encode curly braces etc

[andywebb1975]

https://issues.apache.org/jira/browse/SOLR-17263

Description

HttpJdkSolrClient doesn't encode curly braces etc

NB see also #2454

Solution

Use SolrParams' toQueryString() method rather than implicitly using toString() which doesn't encode all chars.

Tests

I've updated tests to include a curly brace character which should be encoded to %7B, and a length check on the request body content length for PUT/POST requests. Each subsequent commit resolves some of the test failures.

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide

[jdyer1]

Why don't you plan to merge this PR and then I can close out #2435? Your PR looks like a comprehensive fix!

[andywebb1975]

@jdyer1 does this look good to go to you?

Note I've another version which refactors part of the code, I think making it clearer - but let's keep that separate. I've a question in there which applies to the current code too - see #2454. Any thoughts on that?

Andy

[jdyer1]

This bug fix looks fine to me, all it needs is a CHANGES.txt entry.

[janhoy]

Cool. Get this in for 9.6.1 ?