pkg/errors 0.9.1 is a bug fix release for errors 0.9.0. This restore the previous behaviour on Cause method, this behaviour was changed on the PR: #215 and many breaking changes was produced by that.

errors 0.9.0 is a preparation release for a 1.0 final release. Also we were working on removing support for Go 1.8, 1.9 and 1.10 and earlier, and become compatible this package with new way of errors on Go 1.13.

We tried to move into runtime.CallerFrames but this was not possible, you can show the explanation here: Issue 188.

The motivation for do the backward compatible this package with Go 1.13 is that you can migrate the easy way for this to the new way.

Now you could use the methods, Is and As, and the Unwrap() interface like on the standard library.

The method Cause is now compatible with fmt.Errorf("%w", err) and with the Unwrap() interface.

On the same way the methods related with wrapping on this package now are compatible with Cause and Unwrap() interface.

Improvements

• .travis.yml Now use make file.
• reduce allocations when printing stack traces. Thanks @cstockton
• Reduce allocations in Stacktrace.Format
• Add Support to Go 1.13. Thanks @jayschwa, @Sherlock-Holo and @puellanivis.
• Add json.Marshaler support to the Frame type. Thanks @flimzy

Bugs fixed

• .travis.yml Adjust Go versions. Thanks @komuw, @aperezg
• minor fix in an example to print Stack Trace. Thanks @bep.
• Remove not necessary code.
• Clean up documentation. Thanks @seh.

pkg/errors 0.8.1 is a bug fix release for errors 0.8.0. It will be the last version to support Go 1.8 and below. pkg/errors 0.9 and above will require Go 1.9 for the new runtime.CallersFrames API.

pkg/errors 0.8.1 also adds one new feature, errors.WithMessagef. Ideally this would be held over til 0.9, but that complicates the switch to runtime.CallersFrames.

Improvements

• Added errors.WithMessagef. Thanks @chemicL.

Bugs fixed

• .travis.yml. Adjust Go versions. Thanks @AlekSi, @dvrkps, @HaraldNordgren, and @komuw
• Fixed gofmt. Thanks @tariq1890
• Copyedit the package documentation. Thanks @seh, @TomSweeneyRedHat, @nicksnyder, and @beono
• Remove unreachable code. Thanks @philoserf and @haya14busa
• Move benchmark error sink to global variable. Thanks @bradleyfalzon
• Fix minor newline consistency issues in test files. Thanks @nmiyake
• Add doc comment for exported Format func. Thanks @mrhwick and @ihrwein

What's new since version 0.7.1

errors 0.8.0 decomposes Wrap (and Wrapf) into their component operations, namely adding a message to an error, and adding a stack trace to an error, which were previously merged into a single operation.

This is accomplished by adding two top level functions, errors.WithMessage and errors.WithStack, and rewriting Wrap and Wrapf in terms of these operations.

The motivation for this change was need to treat each of the following operations as distinct:

• Adding a context message to an existing error without altering the stack trace.
• Adding a stack trace to an existing error without the requirement of adding an additional message.
• Retrieving the immediate cause of an error; popping one element of the error stack.

The addition of WithStack and WithMessage increases the surface area of this package by two methods, after long discussions at GopherCon 2016 it was felt strongly that destructuring the operation of Wrap and Wrapf was necessary.

For the moment Wrap and Wrapf remain, but depending on your feedback may be deprecated in future releases. Please leave comments via the issue link.

Thanks to @nmiyake and @fabstu for their assistance in preparing this release.

Bug fixes

• Add Go 1.7.1 to .travis.yml. Thanks @Thomasdezeeuw