[codex] Remove unused Rust helpers (#17146)

## Summary

Removes high-confidence unused Rust helper functions and exports across
`codex-tui`, `codex-shell-command`, and utility crates.

The cleanup includes dead TUI helper methods, unused
path/string/elapsed/fuzzy-match utilities, an unused Windows PowerShell
lookup helper, and the unused terminal palette version counter. This
keeps the remaining public surface smaller without changing behavior.

## Validation

- `just fmt`
- `cargo test -p codex-tui -p codex-shell-command -p codex-utils-elapsed
-p codex-utils-fuzzy-match -p codex-utils-string -p codex-utils-path`
- `just fix -p codex-tui -p codex-shell-command -p codex-utils-elapsed
-p codex-utils-fuzzy-match -p codex-utils-string -p codex-utils-path`
- `git diff --check`

codex-rs/shell-command/src/powershell.rs

@@ -68,19 +68,6 @@ pub fn extract_powershell_command(command: &[String]) -> Option<(&str, &str)> {
     None
 }
 
-/// This function attempts to find a valid PowerShell executable on the system.
-/// It first tries to find pwsh.exe, and if that fails, it tries to find
-/// powershell.exe.
-#[cfg(windows)]
-#[allow(dead_code)]
-pub(crate) fn try_find_powershellish_executable_blocking() -> Option<AbsolutePathBuf> {
-    if let Some(pwsh_path) = try_find_pwsh_executable_blocking() {
-        Some(pwsh_path)
-    } else {
-        try_find_powershell_executable_blocking()
-    }
-}
-
 /// This function attempts to find a powershell.exe executable on the system.
 pub fn try_find_powershell_executable_blocking() -> Option<AbsolutePathBuf> {
     try_find_powershellish_executable_in_path(&["powershell.exe"])

codex-rs/tui/src/app_command.rs

@@ -126,11 +126,6 @@ impl AppCommand {
         Self(Op::RealtimeConversationAudio(params))
     }
 
-    #[allow(dead_code)]
-    pub(crate) fn realtime_conversation_text(params: ConversationTextParams) -> Self {
-        Self(Op::RealtimeConversationText(params))
-    }
-
     pub(crate) fn realtime_conversation_close() -> Self {
         Self(Op::RealtimeConversationClose)
     }
@@ -265,16 +260,6 @@ impl AppCommand {
         Self(Op::Review { review_request })
     }
 
-    #[allow(dead_code)]
-    pub(crate) fn kind(&self) -> &'static str {
-        self.0.kind()
-    }
-
-    #[allow(dead_code)]
-    pub(crate) fn as_core(&self) -> &Op {
-        &self.0
-    }
-
     pub(crate) fn into_core(self) -> Op {
         self.0
     }

codex-rs/tui/src/app_server_session.rs

@@ -777,16 +777,6 @@ pub(crate) fn status_account_display_from_auth_mode(
     }
 }
 
-#[allow(dead_code)]
-pub(crate) fn feedback_audience_from_account_email(
-    account_email: Option<&str>,
-) -> FeedbackAudience {
-    match account_email {
-        Some(email) if email.ends_with("@openai.com") => FeedbackAudience::OpenAiEmployee,
-        Some(_) | None => FeedbackAudience::External,
-    }
-}
-
 fn model_preset_from_api_model(model: ApiModel) -> ModelPreset {
     let upgrade = model.upgrade.map(|upgrade_id| {
         let upgrade_info = model.upgrade_info.clone();

codex-rs/tui/src/ascii_animation.rs

@@ -90,11 +90,6 @@ impl AsciiAnimation {
         true
     }
 
-    #[allow(dead_code)]
-    pub(crate) fn request_frame(&self) {
-        self.request_frame.schedule_frame();
-    }
-
     fn frames(&self) -> &'static [&'static str] {
         self.variants[self.variant_idx]
     }

codex-rs/tui/src/chatwidget.rs

@@ -4735,14 +4735,6 @@ impl ChatWidget {
         Self::new_with_op_target(common, CodexOpTarget::AppEvent)
     }
 
-    #[allow(dead_code)]
-    pub(crate) fn new_with_op_sender(
-        common: ChatWidgetInit,
-        codex_op_tx: UnboundedSender<Op>,
-    ) -> Self {
-        Self::new_with_op_target(common, CodexOpTarget::Direct(codex_op_tx))
-    }
-
     fn new_with_op_target(common: ChatWidgetInit, codex_op_target: CodexOpTarget) -> Self {
         let ChatWidgetInit {
             config,

codex-rs/tui/src/live_wrap.rs

@@ -81,11 +81,6 @@ impl RowBuilder {
         self.flush_current_line(/*explicit_break*/ true);
     }
 
-    /// Drain and return all produced rows.
-    pub fn drain_rows(&mut self) -> Vec<Row> {
-        std::mem::take(&mut self.rows)
-    }
-
     /// Return a snapshot of produced rows (non-draining).
     pub fn rows(&self) -> &[Row] {
         &self.rows

codex-rs/tui/src/render/renderable.rs

@@ -200,15 +200,6 @@ impl<'a> ColumnRenderable<'a> {
     pub fn push(&mut self, child: impl Into<Box<dyn Renderable + 'a>>) {
         self.children.push(RenderableItem::Owned(child.into()));
     }
-
-    #[allow(dead_code)]
-    pub fn push_ref<R>(&mut self, child: &'a R)
-    where
-        R: Renderable + 'a,
-    {
-        self.children
-            .push(RenderableItem::Borrowed(child as &'a dyn Renderable));
-    }
 }
 
 pub struct FlexChild<'a> {
@@ -374,15 +365,6 @@ impl<'a> RowRenderable<'a> {
         self.children
             .push((width, RenderableItem::Owned(child.into())));
     }
-
-    #[allow(dead_code)]
-    pub fn push_ref<R>(&mut self, width: u16, child: &'a R)
-    where
-        R: Renderable + 'a,
-    {
-        self.children
-            .push((width, RenderableItem::Borrowed(child as &'a dyn Renderable)));
-    }
 }
 
 pub struct InsetRenderable<'a> {

codex-rs/tui/src/terminal_palette.rs

@@ -1,13 +1,5 @@
 use crate::color::perceptual_distance;
 use ratatui::style::Color;
-use std::sync::atomic::AtomicU64;
-use std::sync::atomic::Ordering;
-
-static DEFAULT_PALETTE_VERSION: AtomicU64 = AtomicU64::new(0);
-
-fn bump_palette_version() {
-    DEFAULT_PALETTE_VERSION.fetch_add(1, Ordering::Relaxed);
-}
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum StdoutColorLevel {
@@ -56,7 +48,6 @@ pub fn best_color(target: (u8, u8, u8)) -> Color {
 
 pub fn requery_default_colors() {
     imp::requery_default_colors();
-    bump_palette_version();
 }
 
 #[derive(Clone, Copy)]
@@ -77,14 +68,6 @@ pub fn default_bg() -> Option<(u8, u8, u8)> {
     default_colors().map(|c| c.bg)
 }
 
-/// Returns a monotonic counter that increments whenever `requery_default_colors()` runs
-/// successfully so cached renderers can know when their styling assumptions (e.g.
-/// background colors baked into cached transcript rows) are stale and need invalidation.
-#[allow(dead_code)]
-pub fn palette_version() -> u64 {
-    DEFAULT_PALETTE_VERSION.load(Ordering::Relaxed)
-}
-
 #[cfg(all(unix, not(test)))]
 mod imp {
     use super::DefaultColors;

codex-rs/utils/elapsed/src/lib.rs

@@ -1,11 +1,4 @@
 use std::time::Duration;
-use std::time::Instant;
-
-/// Returns a string representing the elapsed time since `start_time` like
-/// "1m 15s" or "1.50s".
-pub fn format_elapsed(start_time: Instant) -> String {
-    format_duration(start_time.elapsed())
-}
 
 /// Convert a [`std::time::Duration`] into a human-readable, compact string.
 ///

codex-rs/utils/fuzzy-match/src/lib.rs

@@ -68,15 +68,6 @@ pub fn fuzzy_match(haystack: &str, needle: &str) -> Option<(Vec<usize>, i32)> {
     Some((result_orig_indices, score))
 }
 
-/// Convenience wrapper to get only the indices for a fuzzy match.
-pub fn fuzzy_indices(haystack: &str, needle: &str) -> Option<Vec<usize>> {
-    fuzzy_match(haystack, needle).map(|(mut idx, _)| {
-        idx.sort_unstable();
-        idx.dedup();
-        idx
-    })
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

codex-rs/utils/path-utils/src/env.rs

@@ -1,9 +1,5 @@
 //! Functions for environment detection that need to be shared across crates.
 
-fn env_var_set(key: &str) -> bool {
-    std::env::var(key).is_ok_and(|v| !v.trim().is_empty())
-}
-
 /// Returns true if the current process is running under Windows Subsystem for Linux.
 pub fn is_wsl() -> bool {
     #[cfg(target_os = "linux")]
@@ -21,26 +17,3 @@ pub fn is_wsl() -> bool {
         false
     }
 }
-
-/// Returns true when Codex is likely running in an environment without a usable GUI.
-///
-/// This is intentionally conservative and is used by frontends to avoid flows that would try to
-/// open a browser (e.g. device-code auth fallback).
-pub fn is_headless_environment() -> bool {
-    if env_var_set("CI")
-        || env_var_set("SSH_CONNECTION")
-        || env_var_set("SSH_CLIENT")
-        || env_var_set("SSH_TTY")
-    {
-        return true;
-    }
-
-    #[cfg(target_os = "linux")]
-    {
-        if !env_var_set("DISPLAY") && !env_var_set("WAYLAND_DISPLAY") {
-            return true;
-        }
-    }
-
-    false
-}

codex-rs/utils/path-utils/src/lib.rs

@@ -1,7 +1,6 @@
 //! Path normalization, symlink resolution, and atomic writes shared across Codex crates.
 
 pub(crate) mod env;
-pub use env::is_headless_environment;
 pub use env::is_wsl;
 
 use codex_utils_absolute_path::AbsolutePathBuf;

codex-rs/utils/string/src/lib.rs

@@ -23,28 +23,6 @@ pub fn take_bytes_at_char_boundary(s: &str, maxb: usize) -> &str {
     &s[..last_ok]
 }
 
-// Take a suffix of a &str within a byte budget at a char boundary
-#[inline]
-pub fn take_last_bytes_at_char_boundary(s: &str, maxb: usize) -> &str {
-    if s.len() <= maxb {
-        return s;
-    }
-    let mut start = s.len();
-    let mut used = 0usize;
-    for (i, ch) in s.char_indices().rev() {
-        let nb = ch.len_utf8();
-        if used + nb > maxb {
-            break;
-        }
-        start = i;
-        used += nb;
-        if start == 0 {
-            break;
-        }
-    }
-    &s[start..]
-}
-
 /// Sanitize a tag value to comply with metric tag validation rules:
 /// only ASCII alphanumeric, '.', '_', '-', and '/' are allowed.
 pub fn sanitize_metric_tag_value(value: &str) -> String {