feat: Public methods now return MultiError instead of []error

[thrawn01]

Purpose

The current code base returns multiple errors which is inconvenient to use if multiple errors are not useful to the caller. Instead this PR creates an error that implements the Unwrap() []error method which can be used to retrieve multiple errors. This interface was introduced in go 1.20

Implementation

• Added type MultiError struct
• Added errorMsg() and errorMsgf() (Although that could be narrowed down to just errorMsg() with the capability to handle optional formatted text)

Versioning

This PR significantly breaks compatibility of the public interfaces. If this PR is acceptable, we should bump to v1 before merging.

Postscript

My editor naturally indents with a TAB, and as this project uses SPACES for indentation this PR mixes TABS and SPACES. If this PR is to be accepted I'll fix accordingly.

Reference: https://github.com/pb33f/libopenapi/issues/117

[daveshanley]

Thank you very much for doing this work. I know the change is small, but as you correctly determined, it's a large breaking change for existing consumers - however, it's the right change to make.

We will keep this PR warm until we're ready for 1.0, it should stay healthy and rebase easily when it comes time.

Thank you for your contribution.

(The build is failing btw :-)

[codecov[bot]]

Codecov Report

Patch coverage: 97.01% and no project coverage change.

Comparison is base (a4b7a01) 99.77% compared to head (7c8dcb0) 99.77%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #123   +/-   ##
=======================================
  Coverage   99.77%   99.77%           
=======================================
  Files         146      147    +1     
  Lines       10174    10198   +24     
=======================================
+ Hits        10151    10175   +24     
  Misses         23       23           

Flag	Coverage Δ
unittests	99.77% <97.01%> (+<0.01%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
document.go	97.95% <94.73%> (-0.10%)	:arrow_down:
error.go	100.00% <100.00%> (ø)

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[n0rig]

@thrawn01 do you have time to address the build issues and conflicts?

[thrawn01]

I unfortunately do not, not until the end of the year Feel free to close or take the code as is if you want to use this code as the basis for a new PR.

No need to credit me.