example breaks when path= is replaced with version=

[DougAnderson444]

Summary

When attempting to reproduce the code in the /examples/browser-webrtc directory in a new cargo folder, the example breaks when:

libp2p = { path = "../../libp2p", ...

is replaced with:

libp2p = { version = "0.53.1", ...

Expected behavior

I would expect to be able to drop in the same version = as the lib at path = and compile without issue.

Actual behavior

Example doesn't compile when path= replaced with version=

Relevant log output

error[E0599]: the method `map` exists for struct `Transport`, but its trait bounds were not satisfied
  --> examples/browser-webrtc/src/main.rs:36:14
   |
32 |               Ok(webrtc::tokio::Transport::new(
   |  ________________-
33 | |                 id_keys.clone(),
34 | |                 webrtc::tokio::Certificate::generate(&mut thread_rng())?,
35 | |             )
36 | |             .map(|(peer_id, conn), _| (peer_id, StreamMuxerBox::new(conn))))
   | |             -^^^ method cannot be called on `Transport` due to unsatisfied trait bounds
   | |_____________|
   | 
   |
  ::: /rust-libp2p/transports/webrtc/src/tokio/transport.rs:49:1
   |
49 |   pub struct Transport {
   |   --------------------
   |   |
   |   doesn't satisfy `libp2p_webrtc::tokio::Transport: Iterator`
   |   doesn't satisfy `libp2p_webrtc::tokio::Transport: StreamExt`
   |   doesn't satisfy `libp2p_webrtc::tokio::Transport: futures::Stream`
   |
   = note: the following trait bounds were not satisfied:
           `libp2p_webrtc::tokio::Transport: futures::Stream`
           which is required by `libp2p_webrtc::tokio::Transport: StreamExt`
           `&libp2p_webrtc::tokio::Transport: futures::Stream`
           which is required by `&libp2p_webrtc::tokio::Transport: StreamExt`
           `&mut libp2p_webrtc::tokio::Transport: futures::Stream`
           which is required by `&mut libp2p_webrtc::tokio::Transport: StreamExt`
           `libp2p_webrtc::tokio::Transport: Iterator`
           which is required by `&mut libp2p_webrtc::tokio::Transport: Iterator`
   = help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
   |
3  + use libp2p_core::transport::Transport;
   |

warning: unused import: `futures::StreamExt`
 --> examples/browser-webrtc/src/main.rs:9:5
  |
9 | use futures::StreamExt;
  |     ^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

warning: unused import: `core::Transport`
  --> examples/browser-webrtc/src/main.rs:12:5
   |
12 |     core::Transport,
   |     ^^^^^^^^^^^^^^^

Possible Solution

I'm a bit stumped, as libp2p::core exports Transport, so I'm not really sure what's going on or why the traits would have issues based on the source of the library. The compile error even goes so far as to say that core::Transport is unused!

Version

0.53.1

[DougAnderson444]

Is it possible this is due to the version discrepancy between libp2p-webrtc-websys and ../../libp2p_core?

crate	depends on libp2p-core
crates.io libp2p-webrtc v0.6.0-alpha	v0.40.1
../libp2p/ v0.53.1	v0.41.1

[thomaseizinger]

Ah I think I know what is happening here. It is because libp2p-webrtc-websys is not exported from libp2p, we didn't bump its version in the latest release and thus we simply need a version bump here for this to work :)

Can you send a PR where you bump it to 0.3.0-alpha? We can then release it from there and it should work!

[thomaseizinger]

We should probably start thinking about what it needs to get out of alpha state and just re-export it from libp2p.

[DougAnderson444]

Ok I can do the version bump PR. Actually I realized that the issue is actually on libp2p-webrtc so I can include both in the PR at the same time.

What is the rationale behind not exporting it from libp2p if it is alpha? Would that really cause problems?

[DougAnderson444]

I can confirm the only way I can get the crates to compile is by using the git source instead of crates.io

libp2p = { git = "https://github.com/libp2p/rust-libp2p.git", features = [ "ed25519", "macros", "ping", "tokio"] }
libp2p-webrtc = { git = "https://github.com/libp2p/rust-libp2p.git", features = ["tokio"] }