go-spew vendoring

[ccoVeille]

go-spew can panic when trying to print certain types of values, there are open issues about this on their GitHub repository.

go-spew is unfortunately unmaintained, we cannot expect a fix any time soon.

vendoring go-spew, the same way we vendored go-difflib would help us to remove bugs, but also keep the current pretty print lib without moving to something else.

Note: we have already vendored the go-difflib we are using to compare the go-spew results.

Testify is widely used in Go community. We cannot guess the unpredictable effects it could lead to change the pretty print lib.

See #1061

Related issues

• Panic in assert/require.Equal when calling into go-spew #480

• Catch panic when using go-spew #1824

• don't panic on unexported struct key in map #1816

• assert.Equal panic on diff unexported map with array as key #1813

• maybe others

It would also help to address old issues because we were depending on go-spew, without a chance so see changes being merged upstream

• time.Time rendering

• Make spew config selection configurable to allow for helpful diffs on time.Time objects nested in structs. #1079

• Diffs on structs with nested time.Time objects produce hard to read diffs #1078

• Disable using Stringer/error interfaces for diffing #895

• map

• Diffs are slightly off for assert.Equal on maps #288