Thanks for the great project, it's a huge help for me, just one issue:

Closing an editor normally, e.g. in my case in helix via :q will cause the server to shutdown:

And ra will have to reparse the directory the next time I open it.

If I close by killing the window through my window manager, the server stays active and runs through the intended process of waiting 5 minutes of no activity before shutting down.

Also a minor one but the [DEBUG] and [INFO] messages come through as [ERROR].

Closes #9

1. When ra-multiplex-server fails to invoke the lsp server, display the attempted command.
2. Error if ra-multiplex-server is invoked with the ra-mux-server argument. It should only be passed to the ra-multiplex client.
3. Add ra-multiplex-server --help and -h.

I initially added help text for the client, but I removed it because I think ra-multiplex --help should proxy to rust-analyzer --help.

Thank you for building this crate. It's very handy.

Problem

$ ra-multiplex-server --ra-mux-server /path/to/custom/rust-analyzer &
$ ra-multiplex <...>

then I get:

[INFO ] [32830] client connected
[ERROR] [32830] client error: spawn ra instance

     Caused by:
         0: couldn't spawn rust-analyzer
         1: No such file or directory (os error 2)

Passing --ra-mux-server to ra-multiplex-server doesn't seem to work. ra-multiplex cannot find rust-analyzer.

Solution

You have to pass it via the client. To fix:

$ ra-multiplex-server --ra-mux-server /path/to/custom/rust-analyzer &
$ ra-multiplex --ra-mux-server /path/to/custom/rust-analyzer <...>

Thoughts

1. Does passing --ra-mux-server to the server do anything? If not, should it error?
2. If --ra-mux-server is a valid option to the server: In the absence of a client --ra-mux-server, the server's configuration should take priority.
3. Maybe we could pass ra-mux-server via the config?
4. Maybe this could be spelled out a bit more in the docs? We could kill two birds with one stone by adding a --help?

I am happy to submit PRs for any/all of these. I just wanted to ask first because the intended/correct behavior aren't clear to me.

allow using ra-multiplex with other LSP servers than rust-analyzer. this would require:

• [x] a way of telling the ra-multiplex client which LSP server to use
• [x] more general workspace/project root searching

for the first we can probably use argv[0] since that one is not useful for anything.

for the second we could continue searching for Cargo.toml files if the requested server is rust-analyzer and maybe for a .git directory otherwise. either way we should handle not finding any workspace root gracefully and fall back to just using the provided cwd. the only downside is the servers might not get shared every time depending on where users' editor gets launched from. we could also add an option to mark the workspace root with a .ra-multiplex-workspace-root file

I couldnt get this to work and wasn't sure what steps to take to investigate. Running the ra-multiplex-server doesn't read the config in my home directory (~/config/ra-multiplex/config.toml)

❯ ra-multiplex-server -h
[WARN ] cannot load config: cannot read config file `/Users/tonyalaribe.parity/Library/Application Support/ra-multiplex/config.toml`

    Caused by:
        No such file or directory (os error 2)
^C

b9a14e576f6239563681660b7634ac80183a71e9 bumped the version in Cargo.toml, but the corresponding value in Cargo.lock wasn't updated, which caused me issues when trying to package this in a Nix expression.

This allows ra-multiplex to build on Windows. I tested it with VSCode by setting "rust-analyzer.server.path" to the ra-multiplexer.exe path. It appears to work very well with multiple VSCode windows open on the same project!

Some notes from setting it up:

Unless if I manually create a C:\Users\Michael\AppData\Roaming\ra-multiplex\config\config.toml

# config.toml
arg_parsing = true

the server eventually logs errors like the following

[ERROR] [C:\Program Files\Microsoft VS Code 1972] error reading from stdout: parsing header

    Caused by:
        malformed header, missing \r\n

because r-a's VSCode extension also calls ra-multiplex.exe --version, but without arg_parsing = true, the extension calling the client never receives output (the version), errors like above, then closes that short-lived client.

I haven't made any changes related to this in this pull request (like documentation or different defaults, e.g. always having arg parsing), but I may as well mention if anyone else hits this / before I forget :)

If ~/.config/ra-multiplex/config.toml does not exist, then ra-multiplex-server logs a warning. However, it doesn't indicate in the warning that everything is fine. This led me to believe ra-multiplex-server failed to start.

I recommend logging a message following the warning with something like "Proceeding with default configuration." Something like the following would be nice.

% ra-multiplex-server
[WARN ] cannot load config: cannot read config file `/.../.config/ra-multiplex/config.toml`

    Caused by:
        No such file or directory (os error 2)
[WARN ] Successfully started with default config

tiny fix for:

    Checking ra-multiplex v0.2.0 (src/ra-multiplex)
warning: deref which would be done by auto-deref
   --> src/bin/server/lsp.rs:164:9
    |
164 |         &*self.bytes
    |         ^^^^^^^^^^^^ help: try this: `&self.bytes`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#explicit_auto_deref
    = note: `#[warn(clippy::explicit_auto_deref)]` on by default

warning: deref which would be done by auto-deref
   --> src/bin/server/lsp.rs:182:26
    |
182 |         writer.write_all(&*self.bytes).await?;
    |                          ^^^^^^^^^^^^ help: try this: `&self.bytes`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#explicit_auto_deref

warning: `ra-multiplex` (bin "ra-multiplex-server") generated 2 warnings
    Finished dev [unoptimized + debuginfo] target(s) in 0.35s

This was mentioned in #3, VS Code will try to run rust-analyzer --version which works as expected in the sense that ra-multiplex spawns a new instance with the provided argument, however the output is just a version string and not a valid LSP message which results in a "malformed header" error like:

[ERROR] [C:\Program Files\Microsoft VS Code 1972] error reading from stdout: parsing header

    Caused by:
        malformed header, missing \r\n

Some editors (at least that is the case for Helix), expect a response back from the server upon shutdown. Just closing the socket is not enough and cause the editor to hang.

in order for this to be a full drop-in replacement it could be cool to:

1. start ra-multiplex-server if it's not already running from within ra-multiplex
2. have ra-multiplex-server shut down if it no longer holds any rust-analyzer instances