fix(errors): Show filenames in error message coming from ignore source

[aawsome]

see rustic-rs/rustic#1122

[codecov]

Codecov Report

Attention: Patch coverage is 16.66667% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 30.0%. Comparing base (f3ad6e9) to head (dc965d8).

Additional details and impacted files

Files	Coverage Δ
crates/core/src/error.rs	14.2% <ø> (ø)
crates/core/src/backend/ignore.rs	49.6% <16.6%> (+0.7%)	⬆️

... and 9 files with indirect coverage changes

[simonsan]

Please don't merge these PRs as fast as you do. Between opening and merging were 20 Minutes ... for no apparent reason? This is not a high priority hotfix or anything. So I really don't understand why this has to be merged without any review. Otherwise, I could have brought up the following:

err should be source here as that helps identifying the underlying error.

The Error trait's source() method is implemented to return whichever field has a #[source] attribute or is named source, if any. This is for identifying the underlying lower level error that caused your error.

The #[from] attribute always implies that the same field is #[source], so you don't ever need to specify both attributes.

Any error type that implements std::error::Error or dereferences to dyn std::error::Error will work as a source.

#[derive(Error, Debug)]
pub struct MyError {
    msg: String,
    #[source]  // optional if field name is `source`
    source: anyhow::Error,
}

src.: https://crates.io/crates/thiserror

[aawsome]

We can add this with a follow-up PR. There have been already other errors in error.rs where the same applies.