Provide the SQL statement context

[fractaledmind]

for errors that occur when preparing a SQL statement

@flavorjones @tenderlove @byroot

This is a proof-of-concept PR to explore providing better context for exceptions raised. To begin, I focused on exceptions raised when attempting to prepare a statement. Using the gem over the years, there are other contexts that I found the error messages lacking, but I need to recall them and work on PoCs for each. But I wanted to open this to start the conversation around improving error messages with context.

[flavorjones]

This seems like a great feature to add, if we can clean it up a little bit as suggested by @byroot.

Also please note there's a failing test where we run with an older version of sqlite that doesn't have sqlite3_error_offset. To deal with older versions you'll need to add a have_func in the extconf and then #ifdef HAVE_SQLITE3_ERROR_OFFSET in the code. Let me know if you want any help!

[fractaledmind]

Thank you! I put this WIP PR out there after a quick "hacking session" while prepping talks. I'll get it cleaned up when I'm back from my grad conference adventures.

But, if you have a clear vision and a hacking session to push this over the finish line, I have no sense of ownership over this PR.

Either way, we can get this finished up in October at the latest.

[flavorjones]

I moved the sql error message handling into Ruby and made it backwards-compatible with older versions of sqlite. Would love a bit of review on this if you have a moment @fractaledmind @tenderlove @byroot.

[byroot]

Looks fine to me.

[tenderlove]

LGTM

[fractaledmind]

Looks good to me too. The C code is indeed much better, so thank you all for improving my PoC so considerably. I fixed the merge conflict in the CHANGELOG, so hopefully all the checks pass now.