Return nil values when returning an error

[phillebaba]

A good practice in Go when returning errors is to return nil or empty data for all other return values. It makes sure there is no other potential confusion on the calling end that the data returned is valid and could be used.

Here are some examples where we return data and an error.

zarf/src/pkg/utils/yaml.go

Line 200 in f60b2f4

return objs, fmt.Errorf("failed to unmarshal manifest: %w", err)

zarf/src/pkg/utils/io.go

Line 43 in f60b2f4

return linkedPath, err

zarf/src/pkg/zoci/fetch.go

Line 20 in f60b2f4

return pkg, err

zarf/src/pkg/cluster/zarf.go

Line 281 in f60b2f4

return installedCharts, err

This is slightly related to #2950 and could be done in conjunction with it.

[mkcp]

This isn't the most precise methodology but currently my way of automating this is: for each subdirectory in src/ run
ag "return .*\, err" ./src/$SUBDIR
with the goal of finding error returns without a nil/empty value return.

• api
• cmd
• config (no error returns)
• injector (not golang, as it turns out!)
• internal
• test
• types

pkg

• pkg (gets it own section)
• cluster
• interactive
• layout
• lint
• message
• pki
• transform
• utils
• variables
• zoci

While using using --ignore-dir={./src/pkg/packager,./src/internal/packager,./src/extensions}

If anyone has a sharper way of finding these errors ideas are very welcome.