Make struct InnerError public

[linw1995]

liquid-rust version: 0.26
rust version: 1.64.0
OS: Darwin 22.1.0

I've been trying to handle errors, and try to provide a user-friendly tip. For example, I need to get the requested variable from this error Error { inner: InnerError { msg: "Unknown variable", user_backtrace: [Trace { trace: None, context: [("requested variable", "num")] }], cause: None } }. But due to the InnerError being a private struct, there is nothing I can do then.

[epage]

Sorry for the delay, I was occupied with some family things.

Before discussing how we should support this, could you provide details of what all details you are interested in? And in what ways are you trying to provide tips?

[nickdavies]

I ran into a similar problem although I will admit it's quite niche. I have a usecase where I am trying to do some automatic porting of a large number of templates and I am filtering templates into what features (tags/filters etc) I want to support.

So for me I would love to be able to have access to the internal error details for two reasons:

1. To have more control over the output formatting (Eg I want to put them on a single line or make them more grepable).
2. I would really like to be able to figure out what the root failure is so that I can filter out errors into expected and get more visibility into what tags/filters would unlock the most benefits.