debian-forge-composer/docs/errors.md

Error Handling

When to Panic

Always use panic for errors that can only happen when other code in osbuild-composer is wrong (also know as programmer error). This way, we catch these kinds of errors in unit tests while developing.

Since only developers interact with these errors, a stacktrace including the error is all that's necessary. Don't include an additional message.

For example, Go's json.Marshal can fail when receiving values that cannot be marshaled. However, when passing a known struct, we know it cannot fail:

bytes, err := json.Marshal();
if err != nil {
        panic(err)
}

Some packages have functions prefixed with Must, which panic() on error. Use these when possible to save the error check:

re := regexp.MustCompile("v[0-9]")