v2: invalid delete(, insert?) and splice update operations

[oleg-jukovec]

https://www.tarantool.io/ru/doc/latest/dev_guide/internals/iproto/requests/#examples

IPROTO_UPDATE operation # (delete) could contains 2 (or 3 ?) fields, : (splice) - 5 fields. But we always use 3-fields format:

go-tarantool/client_tools.go

Lines 64 to 69 in c564e6d

	func (o Op) EncodeMsgpack(enc *msgpack.Encoder) error {
	enc.EncodeArrayLen(3)
	enc.EncodeString(o.Op)
	enc.EncodeInt(int64(o.Field))
	return enc.Encode(o.Arg)
	}

[DifferentialOrange]

We also need to explore how Insert works just in case

[oleg-jukovec]

We also need to explore how Insert works just in case

I'm sorry, but I didn't got it. What is meant?

[DifferentialOrange]

We also need to explore how Insert works just in case

I'm sorry, but I didn't got it. What is meant?

Update operation Insert ('!'). There is no documentation entry for what API it got, so there also could be some hidden threats.

[DerekBum]

Here's some facts I found (while searching the docs and trying the operations myself):
(somewhat informative link with examples: https://www.tarantool.io/en/doc/latest/reference/reference_lua/box_space/update/)

1. Delete update # accepts 3 (and only 3) fields. Attempts to pass any other number of elements will resolve in an error: 'Unknown UPDATE operation #1: wrong number of arguments, expected 3, got 2'. The arguments are: operation (#), index of a field in a tuple (from where we need to delete) and the number of fields to delete.
   Example:

tarantool> box.space.bandd:update(1, {{'!', 4, 2}})
---
- [1, '1!!3', 2026, 2]
...

tarantool> box.space.bandd:update(1, {{'!', 5, 3}})
---
- [1, '1!!3', 2026, 2, 3]
...

tarantool> box.space.bandd:update(1, {{'!', 6, 7}})
---
- [1, '1!!3', 2026, 2, 3, 7]
...

tarantool> box.space.bandd:update(1, {{'#', 4, 3}})
---
- [1, '1!!3', 2026]
...

2. Splice operation accepts 5 (and only 5) arguments. There is actually exists already correct and written data structure (with its own EncodeMsgpack) in the code, but not used anywhere:
   

   go-tarantool/client_tools.go

   Lines 144 to 160 in c564e6d

   	type OpSplice struct {
   	Op string
   	Field int
   	Pos int
   	Len int
   	Replace string
   	}
   	func (o OpSplice) EncodeMsgpack(enc *msgpack.Encoder) error {
   	enc.EncodeArrayLen(5)
   	enc.EncodeString(o.Op)
   	enc.EncodeInt(int64(o.Field))
   	enc.EncodeInt(int64(o.Pos))
   	enc.EncodeInt(int64(o.Len))
   	enc.EncodeString(o.Replace)
   	return nil
   	}

3. All other fields accept 3 (and only 3) arguments.

[DerekBum]

As for the fix, we only need to fix the splice operation. I suggest to create an interface (say, operationEncoder) with only one method -- EncodeMsgpack. Make Op and OpSplice a members of this interface and make Operations a struct with an array of operationEncoder elements.
Upsides: not so much to change. Plus, we can create a different implementation for #, +, -, &, |, ^ operations and explicitly check, if their third argument is a number (int) (if needed).
Downsides: there is a bunch of structs in the file, that will also implement operationEncoder (if we left everything as is): IntKey, UintKey, StringKey and so on.

[oleg-jukovec]

Delete update # accepts 3 (and only 3) fields.

Do you check it with IPROTO requests? It could be a little different from a Lua API side.

[oleg-jukovec]

What do you think about to add a bit slice arguments to the Op structure to save the ability to create a custom slice of operations for a user (like in the Lua API):

conn.Do(update.Operations([]Op{{"#", 1, 2}, {"+", 2, 3}, {"!", 1, 2, 3, "foo"}})

Is it possible?

[oleg-jukovec]

We need also to update the crud package:

https://github.com/tarantool/go-tarantool/blob/c564e6d75d10b1bfef276ebacc2eb7cf4acfdb24/crud/operations.go

[DerekBum]

Do you check it with IPROTO requests? It could be a little different from a Lua API side.

For IPROTO requests its the same story. Delete (#), as well as any other operation (except the splice :) takes 3 and only 3 arguments. Splice takes 5 and only 5 arguments.