trunk serve rejects public_url = "./"

[ydirson]

The default public_url = "/" is only suitable when using one server per app, which may not be possible. For example in a project hosted on Github we only get one domain for use with Github Pages.

But we may want to host several version of the app, like in the linked example: public_url = "/" gives an unreasonable constraint, and public_url = "./" gives precisely what is needed, i.e. locating WASM, stylesheets, etc relatively to index.html.

As the linked example shows, this works fine with trunk build, and I am able to generate Github Pages to serve the output of several branches in a single domain, but trunk serve rejects it, apparently due to a check deep inside Axum:

user@perso-dev:leptos-test (master<>)$ RUST_BACKTRACE=1 trunk serve 
2024-02-01T20:41:08.580817Z  INFO 🚀 Starting trunk 0.18.3
2024-02-01T20:41:08.874778Z  INFO 📦 starting build
...
2024-02-01T20:41:12.765645Z  INFO ✅ success
thread 'tokio-runtime-worker' panicked at /home/user/.cargo/registry/src/index.crates.io-6f17d22bba15001f/trunk-0.18.3/src/serve.rs:278:27:
Paths must start with a `/`
stack backtrace:
   0: rust_begin_unwind
             at /rustc/3f28fe133475ec5faf3413b556bf3cfb0d51336c/library/std/src/panicking.rs:645:5
   1: core::panicking::panic_fmt
             at /rustc/3f28fe133475ec5faf3413b556bf3cfb0d51336c/library/core/src/panicking.rs:72:14
   2: axum::routing::Router<S,B>::nest_service
   3: trunk::serve::router
   4: trunk::serve::ServeSystem::spawn_server::{{closure}}::{{closure}}
   5: trunk::serve::ServeSystem::run::{{closure}}::{{closure}}
   6: trunk::serve::ServeSystem::run::{{closure}}
   7: tokio::runtime::task::raw::poll
   8: tokio::runtime::scheduler::multi_thread::worker::Context::run_task
   9: tokio::runtime::task::raw::poll
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
Aborted

[ctron]

Yes, and for good reason. This all goes into the discussion of #668, and I think we should continue the discussion there.

In a nutshell, when using serve, --public-url must be an absolute path. When using build, it can be relative.