The two caveats from the dependency investigation.
## The capabilities feature
Camera and location attachments are now available behind
`features = ["capabilities"]`, which pulls `nigig-uikit` and supplies
`UikitAttachmentProvider`.
Measured: 89 crates by default, 275 with the feature on. That cost is real
and it is inherent, not packaging waste. `camera_widget` imports
`send_geocode_request` and `request_map_tile` from `nigig-core`, both of
which call `spawn_async` — the shared Tokio runtime — and the first makes an
HTTPS call to Nominatim. A camera that geocodes needs an async runtime and an
HTTP client; there is no lighter honest version.
It is affordable because it is opt-in, and because any app enabling it
already depends on `nigig-core`, so that app's own tree grows by nothing.
Everything touching `nigig-uikit` is in one module, so the boundary is a file
rather than `#[cfg]` scattered through the widget. The provider holds no
widgets of its own: the host owns the `CameraWidget` already in its tree and
this asks it to open, because a provider that instantiated a second camera
would fight the first for the device.
A second request while one is outstanding is refused rather than overwriting.
The table turns that refusal into `AttachmentUnavailable`, so the user is
told the camera is busy instead of watching their first request vanish.
File picking is deliberately declined here — `robius-file-picker` already
ships unconditionally and costs nothing, and two paths for one job is one too
many.
Two CI gates, both verified to fail when they should: the opt-in build must
keep compiling, and the default build must pull none of `tokio`, `reqwest`,
`hyper`, `clap`, `csv`, `image`, `nigig-uikit` or `nigig-core`. The second
checks the resolved `cargo tree` rather than the manifest, because feature
unification can switch an optional dependency on from a sibling crate.
Tests 99 default, 105 with the feature. Both clippy-clean.
## The matrix_client defect
Raised in REVIEWS/MATRIX_CLIENT_FEATURE_GATE.md rather than fixed. It is not
my crate, nothing depends on the broken combination, and a blind fix could
change behaviour someone relies on.
`matrix_client` declares `native = ["dep:tokio", "dep:reqwest",
"dep:rusqlite"]` but its source gates on `#[cfg(not(target_arch =
"wasm32"))]`. Two switches for the same modules, so on a native target with
the feature off the modules compile and their dependencies do not — 19
errors, 26 ungated uses across 7 files. There is no CI job for the crate,
which is why it rotted unnoticed.
The note corrects an overstatement I made while arguing for the trait hook.
I said fixing this would unblock wasm. It would not: `matrix_client` already
builds clean for wasm32 with `--no-default-features`, and `nigig-core` has 8
wasm errors of its own (`crate::platform::spawn` missing) that have nothing
to do with it. The only broken combination is native-target-with-feature-off,
which nothing builds.
I also said earlier that `matrix_client` was heavy — it is a 7-dependency
local crate, not matrix-sdk. That was wrong and it inflated the case for the
trait hook; the note records the measured numbers instead.
