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infinity-agent-cli: display truncation slices strings by byte index, can panic on non-ASCII #118
Description
Follow-up to string-related review comments on #115. These byte-index slicing sites pre-date that PR (they exist on main both before and after the change), so they are collected here to be fixed in a separate PR.
Rust string slicing like &s[..n] operates on byte indices and panics if n is not a char boundary. All of the sites below truncate display strings this way. Thread IDs are currently ASCII UUIDs, but with remote-prefixed thread refs (remote/uuid, see #115) a remote name — and session titles already today — can contain non-ASCII, making these potential runtime panics.
Locations
crates/infinity-agent-cli/src/session_picker.rs— session name truncation (both thetitleandidbranches):
let name = if let Some(ref title) = info.title {
if title.len() + extra_len > name_width {
let trunc = name_width.saturating_sub(extra_len + 1);
format!("{}…{}{}", &title[..trunc], remote_label, current_suffix)
...
} else {
let id = id.to_string();
if id.len() + extra_len > name_width {
let trunc = name_width.saturating_sub(extra_len + 1);
format!("{}…{}{}", &id[..trunc], remote_label, current_suffix)
...The title branch is reachable with non-ASCII today (user-provided session titles). Review comment: #115 (comment)
crates/infinity-agent-cli/src/terminal.rs— subscription-event prefix for child threads:
let rendered = child_tid.to_string();
format!("[{}] ", &rendered[..rendered.len().min(8)])Review comment: #115 (comment)
crates/infinity-agent-cli/src/terminal.rs— short thread id in the status/help line:
let tid = tid.to_string();
let short_id = if tid.len() > 8 { &tid[..8] } else { tid.as_str() };Review comment: #115 (comment)
Suggested fix
Use a char-safe (or display-width-aware) truncation instead of byte slicing, e.g.:
s.chars().take(n).collect::<String>(), or&s[..s.floor_char_boundary(n)](stable since Rust 1.93), or- width-based truncation via
unicode-widthfor correct terminal column alignment (note: the surrounding layout math insession_picker.rsalso mixesstr::len()byte lengths withchars().count()when computing label column ranges).
A small shared helper (e.g. fn truncate_display(s: &str, max: usize) -> &str) in infinity-agent-cli would cover all three sites.
Activity
kaluli123123 commentedon Nov 3, 2026
Implemented in draft PR #180 (commit
61ae475854b9eaf6f2a6e35ff117aebd590ad24d).1234567 | /help, child subscription[1234567] ⚡watch: changed, picker123456….1abc6fcff1f186124f924b56aa92c3a3684c90c5(355 passed, 7 failed). No baselines or tolerances were changed.I am maintaining this proposed fix. The PR remains Draft, not ready or merged: full checks are not green, remote CI currently lists no checks, and maintainer review remains outstanding. The repository script skipped docs/UI Prettier because node_modules are absent; optional browser e2e and THIRD-PARTY verification were not reached after the test gate failed. No live model account was used. No merge, Issue closure, or deployment has been performed.