Comparing Go errors

In a Go-based backend service, I update my dependencies. Notably, cloud.google.com/go/storage updated from v1.43.0 to v1.51.0. After deploying, I noticed a werid bug that wasn't happening before. I traced the problem to following code:

import (
    // ...
    gcs "cloud.google.com/go/storage"
    // ...
)

// ...
if err == gcs.ErrObjectNotExist {
    // ...
}

Situations that would previously trigger this conditionally, no longer were. Upon further digging, Google wants you to compare these errors using errors.Is(). This fixed the bug:

if errors.Is(err, gcs.ErrObjectNotExist) {
    // ...
}

Worried, I checked other error checking comparisons (specifically io.EOF) and found this comment above the definition of EOF:

// EOF is the error returned by Read when no more input is available.
// (Read must return EOF itself, not an error wrapping EOF,
// because callers will test for EOF using ==.)

So it looks like in those cases, they prepared for that scenario.