rmux-server 0.10.0: cargo check --all-targets --no-default-features fails, two tests call web-gated functions without a gate #224

Crate: rmux-server, --no-default-features (i.e. without web)
Affected: 0.10.0 and main (1f4571e7). src/handler_attach_tests/set_titles.rs (md5
6841d92f445f0e24d5686a399d0de4a9) and src/handler_attach.rs (md5
ed768880e172a082204fc197092ad15e) are byte-identical across both, so the line numbers below hold
for each. Not affected: 0.9.0 and 0.9.1, where that test file does not exist and the same command
builds clean.
Severity: build break for any consumer that vendors rmux-server without the web feature and
runs its own --all-targets check. The shipped binary is unaffected; only test compilation fails.

Context: I depend on rmux-server with default-features = false because I drive panes over the
local API and have no use for the web share surface, and the check I run is exactly
cargo check --all-targets --no-default-features — which is how this surfaced.

Summary

the_web_and_snapshot_renders_carry_no_title calls two functions that only exist when the web
feature is on, but neither the test nor its module carries a matching gate.

Both definitions carry the gate — src/handler_attach.rs:1271-1272 is #[cfg(feature = "web")]
above pub(super) fn attach_target_for_web_session(, and :1379-1380 is the same pair above
pub(super) fn attach_render_target_for_session_window(. The callers,
src/handler_attach_tests/set_titles.rs:575-593, with no gate anywhere above them:

#[tokio::test]
async fn the_web_and_snapshot_renders_carry_no_title() {          // :576
    // ...
    // Exactly the two entry points handler_web.rs uses.
    let web_attach = crate::handler::attach_support::attach_target_for_web_session(   // :585
        &state, &alpha, 1, &OuterTerminalContext::default(), Path::new("rmux.sock"),
    )
    .expect("web attach target builds");
    let snapshot = crate::handler::attach_support::attach_render_target_for_session_window(  // :593

The module that declares it is ungated too: src/handler_attach_tests.rs:888-889 is a bare
#[path = "handler_attach_tests/set_titles.rs"] mod set_titles;, identical on main.

The feature is named web and is in default. The 0.10.0 features table is
default = ["web"], web = [base64, getrandom, hkdf, httparse, rmux-web-crypto, serde, serde_json, sha1, sha2, subtle, toml, zeroize], plus fuzzing and perf-instrument, both empty.
handler_web.rs, the only non-test caller of both functions, is itself gated — which is why the lib
builds fine and only the test target breaks.

Reproduction

Pristine published crate, no patches, from static.crates.io and verified against the crates.io
API: sha256 2802885d5aa5fb7ff927072103fcaecd458180065892879802df20420ca5204e. Unpack it, then:

cargo check --locked --offline --all-targets --no-default-features

On macOS 15.7.7 arm64, rustc 1.97.1 (8bab26f4f 2026-07-14):

error[E0425]: cannot find function `attach_target_for_web_session` in module `crate::handler::attach_support`
    --> src/handler_attach_tests/set_titles.rs:585:54
     |
 585 |       let web_attach = crate::handler::attach_support::attach_target_for_web_session(
     |                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0425]: cannot find function `attach_render_target_for_session_window` in module `crate::handler::attach_support`
    --> src/handler_attach_tests/set_titles.rs:593:52
     |
 593 |       let snapshot = crate::handler::attach_support::attach_render_target_for_session_window(
     |                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: could not compile `rmux-server` (lib test) due to 2 previous errors; 1 warning emitted

(Each error also carries a ::: note pointing at the ungated neighbours attach_target_for_session
and attach_render_target_for_session_with_prompt; elided above.)

The same command on pristine 0.9.0 (sha256
5b9e539353499018407a602ab5f916288bfa6b07d7a93764eeaf850effff0e8d) and 0.9.1 (sha256
33d3dc789e27ba3cc5c2355f78bd67e196674339c29bf47a2db1f830b233e0aa) finishes with warnings only,
no errors.

Suggested fix

One line, on the single affected test:

--- a/crates/rmux-server/src/handler_attach_tests/set_titles.rs
+++ b/crates/rmux-server/src/handler_attach_tests/set_titles.rs
@@ -572,6 +572,7 @@
 /// The web and snapshot render paths share `render_prelude`, but a browser
 /// client advertises no terminal capabilities at all, so `set-titles on` must
 /// not push OSC 0 / OSC 7 into a snapshot that xterm.js will replay.
+#[cfg(feature = "web")]
 #[tokio::test]
 async fn the_web_and_snapshot_renders_carry_no_title() {

Gating the whole mod set_titles; would also work but is heavier than warranted: the other 13
tests in that file exercise the plain attach render path and compile fine without web.

With that diff applied on an otherwise-pristine 0.10.0 tree I ran:

• cargo check --locked --offline --all-targets --no-default-features — finishes clean, with the
  lib warning count unchanged at 9, so the gate introduces no new dead code. (The unused import: dispatch_with_expected_window_identity at src/handler.rs:219 is pre-existing under
  --no-default-features and is not caused by this change.)
• cargo check --locked --offline --all-targets with default features — finishes clean.
• cargo test --locked --offline --lib the_web_and_snapshot_renders_carry_no_title with default
  features — 1 passed; 0 failed, so the coverage is kept wherever web is on.

Happy to open a PR with exactly that one-line change if you would like it as one.