api: support IPROTO_WATCH_ONCE request type

[DerekBum]

Added support of IPROTO_WATCH_ONCE request type.
It works only for Tarantool version >= 3.0.0-alpha1.

Replaced the local ProtocolFeature type with the iproto.Feature.
Replaced local Feature constants with their iproto.IPROTO_FEATURE_ analogues.

I didn't forget about (remove if it is not applicable):

• Tests (see documentation for a testing package)
• Changelog (see documentation for changelog format)
• Documentation (see documentation for documentation style guide)

Closes #337

[oleg-jukovec]

You also forgot to update client features list:

go-tarantool/protocol.go

Lines 76 to 98 in b6e8aba

	var clientProtocolInfo ProtocolInfo = ProtocolInfo{
	// Protocol version supported by connector. Version 3
	// was introduced in Tarantool 2.10.0, version 4 was
	// introduced in master 948e5cd (possible 2.10.5 or 2.11.0).
	// Support of protocol version on connector side was introduced in
	// 1.10.0.
	Version: ProtocolVersion(4),
	// Streams and transactions were introduced in protocol version 1
	// (Tarantool 2.10.0), in connector since 1.7.0.
	// Error extension type was introduced in protocol
	// version 2 (Tarantool 2.10.0), in connector since 1.10.0.
	// Watchers were introduced in protocol version 3 (Tarantool 2.10.0), in
	// connector since 1.10.0.
	// Pagination were introduced in protocol version 4 (Tarantool 2.11.0), in
	// connector since 1.11.0.
	Features: []ProtocolFeature{
	StreamsFeature,
	TransactionsFeature,
	ErrorExtensionFeature,
	WatchersFeature,
	PaginationFeature,
	},
	}

I also suggest to replace ProtocolFeature constants type:

go-tarantool/protocol.go

Lines 14 to 74 in b6e8aba

	// ProtocolVersion type stores a Tarantool protocol feature.
	type ProtocolFeature uint64
	// ProtocolInfo type aggregates Tarantool protocol version and features info.
	type ProtocolInfo struct {
	// Auth is an authentication method.
	Auth Auth
	// Version is the supported protocol version.
	Version ProtocolVersion
	// Features are supported protocol features.
	Features []ProtocolFeature
	}
	// Clone returns an exact copy of the ProtocolInfo object.
	// Any changes in copy will not affect the original values.
	func (info ProtocolInfo) Clone() ProtocolInfo {
	infoCopy := info
	if info.Features != nil {
	infoCopy.Features = make([]ProtocolFeature, len(info.Features))
	copy(infoCopy.Features, info.Features)
	}
	return infoCopy
	}
	const (
	// StreamsFeature represents streams support (supported by connector).
	StreamsFeature ProtocolFeature = 0
	// TransactionsFeature represents interactive transactions support.
	// (supported by connector).
	TransactionsFeature ProtocolFeature = 1
	// ErrorExtensionFeature represents support of MP_ERROR objects over MessagePack
	// (supported by connector).
	ErrorExtensionFeature ProtocolFeature = 2
	// WatchersFeature represents support of watchers
	// (supported by connector).
	WatchersFeature ProtocolFeature = 3
	// PaginationFeature represents support of pagination
	// (supported by connector).
	PaginationFeature ProtocolFeature = 4
	)
	// String returns the name of a Tarantool feature.
	// If value X is not a known feature, returns "Unknown feature (code X)" string.
	func (ftr ProtocolFeature) String() string {
	switch ftr {
	case StreamsFeature:
	return "StreamsFeature"
	case TransactionsFeature:
	return "TransactionsFeature"
	case ErrorExtensionFeature:
	return "ErrorExtensionFeature"
	case WatchersFeature:
	return "WatchersFeature"
	case PaginationFeature:
	return "PaginationFeature"
	default:
	return fmt.Sprintf("Unknown feature (code %d)", ftr)
	}
	}

By the type Feature from go-iproto package:
https://github.com/tarantool/go-iproto/blob/cb78944739315ca92d64bddf64689e82df4b3cc5/feature.go#L5-L9

[DerekBum]

Updated protocol.go and protocol_test.go. SpaceAndIndexNamesFeature (5) and WatchOnceFeature (6) added.

[oleg-jukovec]

Thank you for the patch!

[DifferentialOrange]

Seems fine, see a couple of nits regarding the description below

[oleg-jukovec]

Please check what is wrong with ExampleSelectRequest_pagination.

[oleg-jukovec]

Please check what is wrong with ExampleSelectRequest_pagination.

Oh, please just rebase to the master branch:
#339