Remove use of `eval`

[jechols]

This is extremely dangerous when processing field settings from untrusted sources: https://github.com/search5/solrpy/blob/master/solr/core.py#L1116

For Open ONI, we're considering just forking the repo to avoid this problem. A simple prototype has verified that it's trivial to construct a "value" which can run arbitrary code before the key check occurs. Given how often data is going to be stored from unknown sources, this just isn't an option for us.

[search5]

Thank you for flagging this critical security concern. This has been resolved in solrpy 2.0.8.

All uses of eval() have been completely removed from the codebase. Response parsing now relies exclusively on json.loads() for JSON responses and a SAX-based XML parser for XML responses — neither of which executes arbitrary code. We have verified
that eval, exec, compile, and import do not appear anywhere in the source. Untrusted data can be safely processed without risk of code injection.