Undefined variable $snippet on line 552

The reason it's undefined is because the test using it is just wrong. It's testing whether the previous result document is empty, which (usually) it never is, as theme('apachesolr_search_snippet') at least returns ' ...'. A more correct test is the one attached. I assume the test in line 552 is whether we have an available snippet yet for this document.

This has become a major issue for me right now as a lot of my content types return empty snippets when using faceted search and no terms are given.

This patch works for me, btw. My snippets are back ;-)

Yes I have the same problem with no snippets showing except for the first item in the list when doing a facet search without keyword. That's because the test on $snippet carries the snippet from the previous doc, and so it never gets set for the next documents!

Patch in #2 solves the problem. Thanks.

It's surprising there is not more "chatter" around this issue as this render non-keyword searches inoperative.

why === 0 instead of e.g. empty(), or even just implicit cast to boolean?

No good reason. if (! $snippets) is better, I agree.

so with that in mind, is the attached patch to everyone's liking?

Duplicate #901720: Highlighting snippets in search results not flexible enough, and logic improvement.. I'll commit it there.