fix(ui): reset message textarea height after sending - #221
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Typing a multi-line message auto-grows the textarea via scrollHeight, but after hitting Enter to send, the textarea stayed expanded instead of shrinking back to one line. The `auto_resize()` call inside `send_message` ran synchronously right after `message_text.set(String::new())`. Dioxus hasn't flushed the signal change to the DOM yet at that point, so `scrollHeight` still reflects the pre-send (expanded) content, and the resize computes the old height. Defer the resize via `crate::util::defer()` so it runs on the next tick after Dioxus has cleared the textarea's `value`. Also pulled the resize logic into a free function — it captures nothing from the component, and making it a plain `fn` avoids move-of-closure issues when passing it to `defer`. Verified in a local browser: 44px initial → 140px with 5-line message → 44px after send. [AI-assisted - Claude] Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Covers #221. Verified the test fails against the pre-fix code (height stays at 140px after Enter-to-send) and passes across all 5 Playwright projects (chromium, firefox, webkit, mobile-chrome, mobile-safari) with the defer-based fix in place. [AI-assisted - Claude] Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
constant_time_eq 0.4.3 was published 2026-04-18 and requires rustc 1.95.0, but rust-toolchain.toml pins rustc to 1.94.1 to keep WASM hashes deterministic (see the comment in that file). Without a committed Cargo.lock, every fresh CI build picked up 0.4.3 and failed at dependency check with "requires rustc 1.95.0". Pin constant_time_eq to 0.4.2 in both the build and ui-playwright-tests jobs before running cargo make. Long-term fix is to either bump the toolchain (requires delegate migration) or commit Cargo.lock; both are out of scope for this PR. [AI-assisted - Claude] Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This was referenced Jul 29, 2026
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Problem
Typing a multi-line message auto-grows the textarea (height follows
scrollHeight, capped at 168px), but after hitting Enter to send, the textarea stayed at its expanded height instead of shrinking back to a single line. The message was cleared, but the input bar took up 4+ lines of empty space until the user typed again.Approach
The
auto_resize()call insidesend_messageran synchronously immediately aftermessage_text.set(String::new()). Dioxus hasn't flushed the signal change to the DOM yet at that point, soscrollHeightstill reflects the pre-send (expanded) content, and the resize computes the old height.Fix: defer the resize via
crate::util::defer()(our wrapper aroundsetTimeout(0)that also pushes the Dioxus runtime + root scope) so it runs on the next tick, after Dioxus has propagated the cleared value to the textarea's DOM.Also pulled the resize logic into a free function. It captures nothing from the component, and making it a plain
fnavoids move-of-closure issues when passing it todefer.Testing
Manually verified in a local browser against
cargo make build-ui-example-no-sync:cargo fmt+cargo clippy -p river-ui --target wasm32-unknown-unknown --features no-syncclean for the touched file.Only UI code changed — no delegate or contract WASM impact, no migration entry needed.
[AI-assisted - Claude]