Better error handling

[o2sh]

The crate error-chain used by onefetch for error handling seems to no longer be maintained.

Anyhow seems to be a good candidate for structuring errors 🤔.

At the same time, this might be an opportunity to improve and homogenize the way we handle/report errors.

• Replace error-chain with anyhow
• Homogenize/improve error handling/reporting
• Avoid the use of unwrap() whenever possible

[HallerPatrick]

Really nice work there! I like the idea of context. They will help a lot with improving error handling/reporting

[spenserblack]

@o2sh Would you want my review now or when the PR is no longer a draft?

[o2sh]

@o2sh Would you want my review now or when the PR is no longer a draft?

If you already have suggestions/comments, the sooner the better 🙏. I chose to keep this PR as a draft because its scope is still not very clear at the moment as it may include more refactoring beside the switch to anyhow.

[spenserblack]

Left some suggestions. All of them are style preference, they shouldn't change the behavior.

One thing I noticed was that you used with_context(|| "foo") a lot. Is there a reason to use that over context("foo")?

[o2sh]

One thing I noticed was that you used with_context(|| "foo") a lot. Is there a reason to use that over context("foo")?

Apparently, it results in better performance in an error-free scenario.