Circular deps between btcutil and btcd, and tons of duplicated deps with different versions because the versions are inconsistent

[benma]

Start a new project go mod init foo, then go get github.com/btcsuite/btcd, then add a main.go

package main

import (
	_ "github.com/btcsuite/btcd"
)

func main() {

}

```

then 
`go mod tidy`.

The resulting `go.sum` has tons of duplicate deps at different versions, for example

```
github.com/btcsuite/btcd v0.20.1-beta/go.mod h1:wVuoA8VJLEcwgqHBwHmzLRazpKxTv13Px/pDuV7OomQ=
github.com/btcsuite/btcd v0.22.0-beta.0.20220111032746-97732e52810c/go.mod h1:tjmYdS6MLJ5/s0Fj4DbLgSbDHbEqLJrtnHecBFkdz5M=
github.com/btcsuite/btcd v0.23.5-0.20231215221805-96c9fd8078fd/go.mod h1:nm3Bko6zh6bWP60UxwoT5LzdGJsQJaPo6HjduXq9p6A=

The reason is that for example, btcd@v0.24.0 references btcutil@v1.1.5:

btcd/go.mod

Line 5 in d55c55a

github.com/btcsuite/btcd/btcutil v1.1.5

while btcutil in turn references btcd@v0.23.5-0.20231215221805-96c9fd8078fd

https://github.com/btcsuite/btcd/blob/d55c55a81f8f9cf2b0fa3cbb83e820ea28173081/btcutil/go.mod#L7C1-L7C64

which in turn references an older btcutil, and so on.

Not sure if there are more such instances.

I am unsure why btcutil is a module of its own, can't it just be a package inside btcd and not a module?

If it has to be a module, btcutil and btcd should ideally not depend on each other.

Barring all of that, the two should point to the same versions.

[kcalvinalvin]

(All things aside) what was the thing you were trying to do? Maybe I could help out there. btcd's main package isn't really meant for outside usage, each of the individual packages are.

[guggero]

We're aware of that. Still looking for reviewers of #1825.

[benma]

@kcalvinalvin

(All things aside) what was the thing you were trying to do? Maybe I could help out there.

We are using it in a few projects and I noticed that I could not get rid of the many duplicated deps and wondered why.

btcd's main package isn't really meant for outside usage, each of the individual packages are.

Why not? It's a perfectly usable library. I make use of the wire package a lot to parse Bitcoin transactions, or use the txscript package for various things. These are not nested modules either - what is the benefit of having btcutil being a nested module?

Nested modules are kind of confusing and seem hard to maintain anyway, seems more natural to just make it a package - would there be a downside to that?

[kcalvinalvin]

Why not? It's a perfectly usable library. I make use of the wire package a lot to parse Bitcoin transactions, or use the txscript package for various things. These are not nested modules either - what is the benefit of having btcutil being a nested module?

Not much besides that it's just been like that.

Nested modules are kind of confusing and seem hard to maintain anyway, seems more natural to just make it a package - would there be a downside to that?

Not that I can think of.