Handle APQ creation errors

[wedneyyuri]

We are planning to create APQ during build time, shipping only the hash of the query to our client but there's no way no way to know if the APQ was not saved.

gqlgen/graphql/handler/extension/apq.go

Lines 85 to 89 in 27a2b21

	// client sent optimistic query hash with query string, verify and store it
	if computeQueryHash(rawParams.Query) != extension.Sha256 {
	return gqlerror.Errorf("provided APQ hash does not match query")
	}
	a.Cache.Add(ctx, extension.Sha256, rawParams.Query)

The better option would be to return error in case of cache failure, if this error must be ignored it can be done when implementing the interface graphql.Cache:

gqlgen/graphql/cache.go

Lines 6 to 12 in 27a2b21

	type Cache interface {
	// Get looks up a key's value from the cache.
	Get(ctx context.Context, key string) (value interface{}, ok bool)
	// Add adds a value to the cache.
	Add(ctx context.Context, key string, value interface{})
	}