fix(viewer,cli,export): clear the remaining 30 clippy lints

`cargo clippy --workspace -- -D warnings` now exits 0. `cargo test
--workspace` still reports 207 passed, 0 failed, 14 ignored across 30
suites — identical to runs 203 and 204, so none of this changed behaviour.

The workspace total was 73, not the 48 run 204 reported. `-D warnings`
turns a lint into a hard compile error, so `sylpheed-formats` failing
stopped its dependents from ever being built: `sylpheed-viewer` (14) and
`sylpheed-cli` (11) had never been linted by anyone. Clearing formats in
5c35a34 is what made them visible.

  formats  43 -> 0   (5c35a34)
  viewer   14 -> 0
  cli      11 -> 0
  export    5 -> 0

Collision surface, measured rather than assumed. Every viewer file
carrying a lint is byte-identical on both `auto/frame-blend-draw-path`
(495 commits) and `auto/port-p6-audio` (366). All eleven cli sites fall
outside every hunk either branch touches. 68 of the 73 sites could not
collide with anything.

The five that can are all in `sylpheed-export`, and three of those are
real:

  main.rs:278   `&out` -> `out`, inside frame-blend's hunk -278,12
  main.rs:318   `&out` -> `out`, inside port-p6-audio's hunk -303,44
  audio.rs:113  an added `#[allow]` in a file frame-blend DELETES

Each is one line. Resolving the first two means taking the branch's
version and re-applying a borrow removal; the third resolves to the
deletion. Flagged here so neither branch owner meets them cold.

Judgement calls, all stated at the site rather than suppressed globally:

* Three `too_many_arguments` in the viewer are false positives.
  `draw_viewer_ui`, `poll_loader_channel` and `apply_pak` are Bevy
  systems — every parameter is a `Res`/`ResMut`/`EventWriter` the
  scheduler injects, so the count is the framework's dependency list and
  cannot be reduced without a `SystemParam` struct.
* `cmd_screen_render` (cli, 8/7) is a plain function, so that one is real
  if mild; its arguments are the subcommand's flags.
* Two `dead_code` fields in export are serde schema fields. They model
  what the on-disc JSON accepts; deleting them would quietly change that.
* `iso_loader.rs` gains a `FrameRx` alias for the ffmpeg frame channel,
  which is what "very complex type" was asking for.

A site-local `#[allow]` with a reason is a decision recorded where it
applies: one lint, one function, and any new violation elsewhere still
fails the build. That is not the shape PROTOCOL.md forbids.

Closes #13

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01McNbzUeq1KRBWs4G6X2YVj

.github/workflows/ci.yml

@@ -42,7 +42,15 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install Rust toolchain
+        # `stable` installs a MINIMAL profile: rustc, cargo, rust-std and no
+        # more. Components have to be named. Without this line the Clippy step
+        # below dies on "'cargo-clippy' is not installed for the toolchain
+        # 'stable-aarch64-unknown-linux-gnu'" — which is not a lint result, it
+        # is the step never having run. The `fmt` job below always got this
+        # right; this one never did.
         uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy
 
       - name: Cache Cargo registry and build
         uses: Swatinem/rust-cache@v2
@@ -69,6 +77,20 @@ jobs:
       - name: Run tests
         run: cargo test --workspace
 
+      # This step has never once executed on this codebase: the toolchain above
+      # shipped without the component, so every run died on "not installed"
+      # before clippy saw a line of source. Its result was never pass or fail,
+      # only unmeasured. With the component installed it becomes a real check,
+      # and the first honest thing it will report is that the workspace is not
+      # clean — the build already emits ~13 plain rustc warnings (unused
+      # imports, unused variables, needless `mut`, dead fields) that
+      # `-D warnings` promotes to errors, before clippy's own lints are counted.
+      #
+      # Left gating on purpose. A red check that measures something is worth
+      # more than a green one that measures nothing, and the alternative —
+      # `continue-on-error`, or dropping `-D warnings` — cannot tell "debt not
+      # yet paid" from "debt paid", which is the shape PROTOCOL.md forbids.
+      # The debt is scoped in #13, as the rustfmt debt is in #12.
       - name: Clippy
         run: cargo clippy --workspace -- -D warnings
 

crates/sylpheed-cli/src/main.rs

@@ -38,7 +38,6 @@ use anyhow::{Context, Result};
 use clap::{Parser, Subcommand};
 use colored::*;
 use indicatif::{ProgressBar, ProgressStyle};
-use tracing::info;
 
 use sylpheed_formats::vfs::{identify_format, GameAssets};
 use sylpheed_formats::{IdxdObject, PakArchive};
@@ -572,6 +571,11 @@ fn print_geometry(b: &sylpheed_formats::ui_layout::UiBuild, bytes: &[u8]) {
     }
 }
 
+// 8 parameters against a threshold of 7 — a plain function, unlike the Bevy
+// systems in the viewer, so this one is real if mild. Left as-is because the
+// arguments are the CLI flags this subcommand takes; grouping them into a
+// struct is a change to the command surface, not a lint fix.
+#[allow(clippy::too_many_arguments)]
 fn cmd_screen_render(
     pak: &Path,
     output: &Path,
@@ -892,7 +896,7 @@ fn cmd_sniff(dir: &Path, unknown_only: bool) -> Result<()> {
     println!();
     println!("{}", "Format Summary:".bold());
     let mut summary: Vec<_> = counts.into_iter().collect();
-    summary.sort_by(|a, b| b.1.cmp(&a.1));
+    summary.sort_by_key(|&(_, count)| std::cmp::Reverse(count));
     for (fmt, count) in summary {
         println!(
             "  {:>6}  .{}",
@@ -1034,7 +1038,7 @@ fn cmd_mesh_info(file: &Path) -> Result<()> {
             let nv = sub.positions.len();
             let mut referenced = vec![false; nv];
             let (mut degen, mut oob, mut imax) = (0usize, 0usize, 0u32);
-            for tri in sub.indices.chunks_exact(3) {
+            for tri in sub.indices.as_chunks::<3>().0 {
                 let (a, b, c) = (tri[0], tri[1], tri[2]);
                 imax = imax.max(a).max(b).max(c);
                 if a == b || b == c || a == c {
@@ -1056,7 +1060,7 @@ fn cmd_mesh_info(file: &Path) -> Result<()> {
             };
             let mut maxedges: Vec<f32> = sub
                 .indices
-                .chunks_exact(3)
+                .as_chunks::<3>().0.iter()
                 .map(|t| edge(t[0], t[1]).max(edge(t[1], t[2])).max(edge(t[0], t[2])))
                 .collect();
             maxedges.sort_by(|a, b| a.partial_cmp(b).unwrap());
@@ -1220,7 +1224,7 @@ fn cmd_mesh_render(
             let med = {
                 let mut e: Vec<f32> = sub
                     .indices
-                    .chunks_exact(3)
+                    .as_chunks::<3>().0.iter()
                     .filter(|t| (t[0] as usize) < n && (t[1] as usize) < n && (t[2] as usize) < n)
                     .map(|t| {
                         let d = |a: u32, b: u32| {
@@ -1254,7 +1258,7 @@ fn cmd_mesh_render(
                         (p[2] - center[2]) * scale * mirror[2] + cell[2],
                     ]
                 };
-                for tri in sub.indices.chunks_exact(3) {
+                for tri in sub.indices.as_chunks::<3>().0 {
                     let (a, b, c) = (tri[0] as usize, tri[1] as usize, tri[2] as usize);
                     if a < n && b < n && c < n {
                         if span_only || span_hide {
@@ -1440,7 +1444,7 @@ fn decode_to_rgba8(tex: &sylpheed_formats::texture::X360Texture) -> Result<Vec<u
             // [A,R,G,B] byte order (verified against the retail Acheron backdrop).
             // Emit RGBA. X8 has no meaningful alpha.
             let opaque = matches!(tex.format, F::X8R8G8B8);
-            for (px, out) in tex.data.chunks_exact(4).zip(rgba.chunks_exact_mut(4)) {
+            for (px, out) in tex.data.as_chunks::<4>().0.iter().zip(rgba.as_chunks_mut::<4>().0) {
                 out[0] = px[1]; // R
                 out[1] = px[2]; // G
                 out[2] = px[3]; // B
@@ -1690,12 +1694,12 @@ fn cmd_pak_textures(pak: &Path, output: &Path, verbose: bool) -> Result<()> {
             let mut idx = 0usize;
             while let Some(pos) = payload[off..]
                 .windows(4)
-                .position(|w| w == &t8ad::T8AD_MAGIC)
+                .position(|w| w == t8ad::T8AD_MAGIC)
             {
                 let start = off + pos;
                 let next = payload[start + 4..]
                     .windows(4)
-                    .position(|w| w == &t8ad::T8AD_MAGIC)
+                    .position(|w| w == t8ad::T8AD_MAGIC)
                     .map(|p| start + 4 + p)
                     .unwrap_or(payload.len());
                 emit_t8ad(

crates/sylpheed-export/src/audio.rs

@@ -109,6 +109,8 @@ pub struct BgmSpec {
     pub loop_start_s: Option<f64>,
     #[serde(default)]
     pub loop_end_s: Option<f64>,
+    // Deserialised to model the sidecar schema, not read in Rust.
+    #[allow(dead_code)]
     #[serde(default)]
     pub loop_end_why: Option<serde_json::Value>,
     #[serde(default)]

crates/sylpheed-export/src/main.rs

@@ -158,6 +158,9 @@ fn load_names(authored: &Path) -> Result<NameMap> {
     #[derive(serde::Deserialize)]
     struct File {
         archives: NameMap,
+        // Deserialised to model the on-disc schema, not read in Rust.
+        // Removing it would silently change what this struct accepts.
+        #[allow(dead_code)]
         #[serde(default)]
         also_export: AlsoExport,
     }
@@ -275,7 +278,7 @@ fn run_export(disc: &Path, out: &Path, authored_dir: &Path) -> Result<()> {
     // `video/` that this run did not claim, so a movie that stops being exported
     // still stops existing.
     if out.exists() {
-        for entry in std::fs::read_dir(&out).context("clear the output tree")? {
+        for entry in std::fs::read_dir(out).context("clear the output tree")? {
             let entry = entry?;
             if entry.file_name() == "video" {
                 continue;
@@ -288,7 +291,7 @@ fn run_export(disc: &Path, out: &Path, authored_dir: &Path) -> Result<()> {
             .with_context(|| format!("clear {}", entry.path().display()))?;
         }
     }
-    std::fs::create_dir_all(&out)?;
+    std::fs::create_dir_all(out)?;
 
     let archive = "dat/GP_TITLE.pak";
     let pak = disc.join(archive);
@@ -315,7 +318,7 @@ fn run_export(disc: &Path, out: &Path, authored_dir: &Path) -> Result<()> {
             None => (format!("build_{entry:02}"), "index", None),
         };
         let ex = screen::export_build(
-            &out,
+            out,
             archive,
             *entry,
             build_idx,

crates/sylpheed-formats/src/audio.rs

@@ -226,9 +226,10 @@ fn parse_riff_wave(bytes: &[u8]) -> Option<AudioInfo> {
     match codec {
         AudioCodec::Pcm | AudioCodec::PcmFloat => {
             if let (Some(d), true) = (data_bytes, channels > 0 && bits > 0) {
+                // `bits` under 8 makes the frame size zero, so this stays
+                // fallible: `checked_div` states that once, where it happens.
                 let frame = channels as u64 * (bits as u64 / 8);
-                if frame > 0 {
-                    let spc = d / frame;
+                if let Some(spc) = d.checked_div(frame) {
                     info.samples_per_channel = Some(spc);
                     if rate > 0 {
                         info.duration_secs = Some(spc as f32 / rate as f32);
@@ -275,11 +276,11 @@ impl GameAudio {
         let samples: Vec<f32> = match (info.codec, bits) {
             (AudioCodec::Pcm, 8) => data.iter().map(|&b| (b as f32 - 128.0) / 128.0).collect(),
             (AudioCodec::Pcm, 16) => data
-                .chunks_exact(2)
+                .as_chunks::<2>().0.iter()
                 .map(|c| i16::from_le_bytes([c[0], c[1]]) as f32 / 32768.0)
                 .collect(),
             (AudioCodec::Pcm, 24) => data
-                .chunks_exact(3)
+                .as_chunks::<3>().0.iter()
                 .map(|c| {
                     let v = ((c[2] as i32) << 16) | ((c[1] as i32) << 8) | c[0] as i32;
                     let v = (v << 8) >> 8; // sign-extend 24→32
@@ -287,7 +288,7 @@ impl GameAudio {
                 })
                 .collect(),
             (AudioCodec::PcmFloat, 32) => data
-                .chunks_exact(4)
+                .as_chunks::<4>().0.iter()
                 .map(|c| f32::from_le_bytes([c[0], c[1], c[2], c[3]]))
                 .collect(),
             _ => return Err(AudioError::UnsupportedPcm { tag: 0, bits }),

crates/sylpheed-formats/src/game_data.rs

@@ -1131,7 +1131,7 @@ pub fn load_squadrons(pak: &PakArchive) -> Vec<Squadron> {
             let Some(f) = records.record(id) else { continue };
             let slots: Vec<&str> = f.positional.iter().map(|(_, v)| v.as_str()).collect();
             let members = slots
-                .chunks_exact(4)
+                .as_chunks::<4>().0.iter()
                 .map(|m| SquadronMember {
                     unit: m[0].to_string(),
                     message_set: text(Some(m[1])),

crates/sylpheed-formats/src/hash.rs

@@ -71,7 +71,7 @@ pub fn name_hash(name: &str) -> u32 {
     // through untouched, including any high-bit bytes, which are then sign-extended).
     let mut bytes = name.as_bytes().to_vec();
     for byte in &mut bytes {
-        if (b'A'..=b'Z').contains(byte) {
+        if byte.is_ascii_uppercase() {
             *byte += 0x20;
         }
     }

crates/sylpheed-formats/src/ixud.rs

@@ -119,7 +119,7 @@ pub fn parse(bytes: &[u8]) -> Option<Subtitle> {
 fn utf16be_tokens(bytes: &[u8]) -> Vec<String> {
     let mut tokens = Vec::new();
     let mut cur = String::new();
-    for pair in bytes.chunks_exact(2) {
+    for pair in bytes.as_chunks::<2>().0 {
         let u = u16::from_be_bytes([pair[0], pair[1]]);
         match char::from_u32(u as u32) {
             Some(c) if !c.is_control() => cur.push(c),

crates/sylpheed-formats/src/mesh.rs

@@ -700,7 +700,7 @@ impl Xbg7Model {
                 let (vc, ic) = r.markers[0];
                 let sig = (r.decl.stride, vc, ic);
                 let floor = last_by_sig.get(&sig).map_or(0, |o| o + 1);
-                if m.meshes[0].vbuf_offset.map_or(false, |o| o < floor) {
+                if m.meshes[0].vbuf_offset.is_some_and(|o| o < floor) {
                     if let Some(alt) = anchor_pool_mesh(
                         bytes,
                         starts,
@@ -1339,6 +1339,13 @@ fn vertex_run_starts(bytes: &[u8], data_base: usize, stride: usize) -> Vec<usize
 /// the `index_count` indices ending just before it are all `< vtx_count`,
 /// reference (nearly) all vertices, and produce non-degenerate triangles with a
 /// real spatial extent — a signature strong enough to pin the block.
+// 8 parameters against clippy's threshold of 7. Not refactored here on
+// purpose: the fix is a shared params struct across this and the two
+// `validate_block*` functions below, which is a change to the decoder's
+// mesh-anchoring signatures and belongs to whoever owns that path — not to
+// a CI-lint pass. Recorded rather than silenced: this allow covers one lint
+// at one site, and any new violation elsewhere still fails the build.
+#[allow(clippy::too_many_arguments)]
 fn anchor_pool_mesh(
     bytes: &[u8],
     starts: &[usize],
@@ -1406,7 +1413,7 @@ fn anchor_pool_mesh(
                 }
                 let (degen, wind) = index_run_quality(bytes, ib, vb, index_count, decl);
                 let cand = (degen, -wind, pad);
-                if best.map_or(true, |b| cand < b) {
+                if best.is_none_or(|b| cand < b) {
                     best = Some(cand);
                 }
             }
@@ -1452,6 +1459,11 @@ fn anchor_pool_mesh(
 /// for both the adjacency anchor ([`anchor_pool_mesh`]) and the grouped-pool
 /// anchor ([`anchor_grouped_meshes`]); the two differ only in how they *place*
 /// `ib`/`vb`, not in how they validate a placement.
+// 8/7, as above. This and `validate_block_report` take the *same* eight
+// parameters — one delegates straight to the other — which is exactly why a
+// params struct is the right fix and why it should be done once, deliberately,
+// rather than piecemeal here.
+#[allow(clippy::too_many_arguments)]
 fn validate_block(
     bytes: &[u8],
     ib: usize,
@@ -1478,6 +1490,8 @@ fn validate_block(
 /// [`validate_block`], but naming the gate that rejected a block. A runtime
 /// capture can prove a block is real; when the decoder still refuses it, this
 /// says which test is wrong rather than leaving a threshold to be guessed at.
+// 8/7 — the signature `validate_block` delegates into. See above.
+#[allow(clippy::too_many_arguments)]
 fn validate_block_report(
     bytes: &[u8],
     ib: usize,
@@ -1679,7 +1693,7 @@ fn anchor_grouped_meshes(
     if n == 0 || decls.len() < n {
         return Vec::new();
     }
-    let decl = &decls[0];
+    let _decl = &decls[0];
 
     // Relative index-buffer offsets (ib0 = 0), 4-byte aligned between buffers,
     // and cumulative vertex offsets (vb0 = 0) — both derived from the marker list.
@@ -1723,7 +1737,7 @@ fn anchor_grouped_meshes(
             let (vc, ic) = markers[i];
             let ib = ib0 + rel_ib[i];
             if ib + ic * 2 > bytes.len()
-                || vc.checked_mul(decls[i].stride).map_or(true, |b| vb + b > bytes.len())
+                || vc.checked_mul(decls[i].stride).is_none_or(|b| vb + b > bytes.len())
             {
                 break;
             }
@@ -1784,7 +1798,7 @@ fn anchor_grouped_meshes(
             }
             let (degen, wind) = index_run_quality(bytes, ib_k, vb_k, ick, &decls[kmax]);
             let cand = (degen, -wind, pad);
-            if best.map_or(true, |b| cand < b) {
+            if best.is_none_or(|b| cand < b) {
                 best = Some(cand);
             }
             if pad_first_match() {
@@ -1797,7 +1811,7 @@ fn anchor_grouped_meshes(
             if meshes.len() == n {
                 return meshes;
             }
-            if partial.as_ref().map_or(true, |p| meshes.len() > p.len()) {
+            if partial.as_ref().is_none_or(|p| meshes.len() > p.len()) {
                 partial = Some(meshes);
             }
         }
@@ -1929,7 +1943,7 @@ fn find_index_marker(desc: &[u8]) -> Option<(usize, usize)> {
     while rel + 40 <= desc.len() {
         let a = be32(desc, rel);
         let c = be32(desc, rel + 4);
-        if c >= 3 && c % 3 == 0 && c < 400_000 && a == c * 2 {
+        if c >= 3 && c.is_multiple_of(3) && c < 400_000 && a == c * 2 {
             return Some((rel, c as usize));
         }
         rel += 4;
@@ -1951,7 +1965,7 @@ fn all_index_markers(desc: &[u8]) -> Vec<(usize, usize)> {
     while rel + 8 <= desc.len() {
         let a = be32(desc, rel);
         let c = be32(desc, rel + 4);
-        if c >= 3 && c % 3 == 0 && c < 400_000 && a == c * 2 && rel >= 32 {
+        if c >= 3 && c.is_multiple_of(3) && c < 400_000 && a == c * 2 && rel >= 32 {
             let vc = be32(desc, rel - 32) as usize;
             if (3..=200_000).contains(&vc) {
                 out.push((vc, c as usize));
@@ -1979,7 +1993,7 @@ fn all_vertex_decls(desc: &[u8]) -> Vec<VertexDecl> {
     while rel + 8 <= desc.len() {
         let a = be32(desc, rel);
         let c = be32(desc, rel + 4);
-        if c >= 3 && c % 3 == 0 && c < 400_000 && a == c * 2 && rel >= 32 {
+        if c >= 3 && c.is_multiple_of(3) && c < 400_000 && a == c * 2 && rel >= 32 {
             let vc = be32(desc, rel - 32) as usize;
             if (3..=200_000).contains(&vc) {
                 match parse_decl_at(desc, rel + 8) {
@@ -2086,9 +2100,8 @@ fn submesh_records(desc: &[u8]) -> Vec<(usize, usize)> {
         let t = be32(desc, rel + 12);
         if (3..=65535).contains(&a)
             && z == 0
-            && c >= 3
-            && c <= 200_000
-            && c % 3 == 0
+            && (3..=200_000).contains(&c)
+            && c.is_multiple_of(3)
             && (1..=64).contains(&t)
         {
             out.push((a as usize, c as usize));
@@ -2151,7 +2164,7 @@ fn topology_report(
     let mut agree = 0usize;
     let mut counted = 0usize;
     let mut edges: HashMap<(u32, u32), u32> = HashMap::new();
-    for t in indices.chunks_exact(3) {
+    for t in indices.as_chunks::<3>().0 {
         let (a, b, c) = (t[0] as usize, t[1] as usize, t[2] as usize);
         if a == b || b == c || a == c {
             degen += 1;
@@ -2330,7 +2343,7 @@ pub fn submesh_albedos(bytes: &[u8], resource_name: &str) -> Vec<(usize, usize,
         if (3..=65535).contains(&vtx)
             && z == 0
             && idx >= 3
-            && idx % 3 == 0
+            && idx.is_multiple_of(3)
             && idx < 400_000
             && tail > 0
             && tail < 0x10_0000
@@ -2423,7 +2436,7 @@ pub fn material_groups(bytes: &[u8], resource_name: &str, target: usize) -> Vec<
         if (1..=70000).contains(&vtx)
             && tail == 4
             && cnt >= 3
-            && cnt % 3 == 0
+            && cnt.is_multiple_of(3)
             && cnt < 400_000
             && (off as usize) < 4_000_000
         {

crates/sylpheed-formats/src/movie_manifest.rs

@@ -2,7 +2,7 @@
 //! table (statically reversed). Beyond the movie→voice binding, it defines the
 //! whole cutscene *structure*: which video (+ subtitle, + on-screen text overlay,
 //! + voice) plays at each mission phase, and of what kind (story intro, in-mission
-//! phase cutscene, resupply, …).
+//!   phase cutscene, resupply, …).
 //!
 //! ## On-disc structure (`dat/tables.pak`, entry hash `0x5b983a08`)
 //!

crates/sylpheed-formats/src/movie_voice.rs

@@ -96,7 +96,7 @@ pub fn find_descriptor_before(buf: &[u8], before: usize) -> Option<usize> {
     let mut o = (before - 1).min(cap) & !3;
     loop {
         let id = be(o);
-        if id >= 1 && id < ID_MAX && be(o + 4) == DESC_MARK && be(o + DESC_REPEAT) == id {
+        if (1..ID_MAX).contains(&id) && be(o + 4) == DESC_MARK && be(o + DESC_REPEAT) == id {
             return Some(o);
         }
         if o < 4 {

crates/sylpheed-formats/src/ship_capture.rs

@@ -287,7 +287,7 @@ pub fn parse_drawlog(text: &str) -> Vec<CapturedDraw> {
     let mut pos: Vec<[f32; 3]> = Vec::new();
     let mut consts: Vec<(usize, [f64; 4])> = Vec::new();
 
-    let mut flush = |base: u32,
+    let flush = |base: u32,
                      size: u32,
                      stride: u32,
                      pos: &mut Vec<[f32; 3]>,
@@ -426,7 +426,7 @@ pub fn correlate(
             let Some((score, mirrored)) = pos_validate(d, &key.ref_pos) else {
                 continue; // positions disagree — not this part
             };
-            if best.map_or(true, |(_, s, _)| score > s) {
+            if best.is_none_or(|(_, s, _)| score > s) {
                 best = Some((d, score, mirrored));
             }
         }

crates/sylpheed-formats/src/slb.rs

@@ -517,7 +517,7 @@ pub fn to_xma_riff_best(slb: &[u8]) -> Option<Vec<u8>> {
     while let Some(di) = find(slb, b"data", i) {
         let declared = le32(slb, di + 4).unwrap_or(0) as usize;
         let usable = declared.min(slb.len().saturating_sub(di + 8));
-        if best.map_or(true, |(_, b)| usable > b) {
+        if best.is_none_or(|(_, b)| usable > b) {
             best = Some((di, usable));
         }
         i = di + 4;

crates/sylpheed-formats/src/texture.rs

@@ -587,19 +587,19 @@ pub fn apply_endian_swap(data: &mut [u8], endianness: u8) {
     match endianness {
         1 => {
             // k8in16 — swap the two bytes of each 16-bit half.
-            for c in data.chunks_exact_mut(2) {
+            for c in data.as_chunks_mut::<2>().0 {
                 c.swap(0, 1);
             }
         }
         2 => {
             // k8in32 — reverse each 32-bit word.
-            for c in data.chunks_exact_mut(4) {
+            for c in data.as_chunks_mut::<4>().0 {
                 c.reverse();
             }
         }
         3 => {
             // k16in32 — swap the two 16-bit halves of each 32-bit word.
-            for c in data.chunks_exact_mut(4) {
+            for c in data.as_chunks_mut::<4>().0 {
                 c.swap(0, 2);
                 c.swap(1, 3);
             }
@@ -626,8 +626,8 @@ fn decode_surface(
     } else {
         // Linear layout — copy only the mip-0 slice.
         let block_size = format.block_size() as u32;
-        let bw = ((width + block_size - 1) / block_size).max(1);
-        let bh = ((height + block_size - 1) / block_size).max(1);
+        let bw = width.div_ceil(block_size).max(1);
+        let bh = height.div_ceil(block_size).max(1);
         let needed = bw as usize * bh as usize * format.bytes_per_block();
         if raw_data.len() < needed {
             return Err(TextureError::BufferTooSmall { needed, have: raw_data.len() });
@@ -651,7 +651,7 @@ fn decode_surface(
         match format {
             X360TextureFormat::Dxt1 => swap_bc_block_dwords(&mut linear_data),
             X360TextureFormat::Dxt3 | X360TextureFormat::Dxt5 => {
-                for block in linear_data.chunks_exact_mut(16) {
+                for block in linear_data.as_chunks_mut::<16>().0 {
                     swap_bc_block_dwords(&mut block[8..16]);
                 }
             }
@@ -666,8 +666,8 @@ fn decode_surface(
 /// rounded up to the 4 KiB subresource alignment (`kTextureSubresourceAlignmentBytes`).
 fn tiled_face_stride(width: u32, height: u32, format: X360TextureFormat) -> usize {
     let bs = format.block_size() as u32;
-    let bw = ((width + bs - 1) / bs).max(1);
-    let bh = ((height + bs - 1) / bs).max(1);
+    let bw = width.div_ceil(bs).max(1);
+    let bh = height.div_ceil(bs).max(1);
     let pitch_aligned = align_up(bw, STORAGE_ALIGN_BLOCKS).max(MACRO_TILE_BLOCKS);
     let height_aligned = align_up(bh, STORAGE_ALIGN_BLOCKS).max(MACRO_TILE_BLOCKS);
     let surface = pitch_aligned as usize * height_aligned as usize * format.bytes_per_block();
@@ -682,7 +682,7 @@ fn tiled_face_stride(width: u32, height: u32, format: X360TextureFormat) -> usiz
 /// after the byte-level endian swap. Any trailing bytes that don't fill a full
 /// 8-byte group are left untouched.
 pub fn swap_bc_block_dwords(data: &mut [u8]) {
-    for unit in data.chunks_exact_mut(8) {
+    for unit in data.as_chunks_mut::<8>().0 {
         // [d0 d1 d2 d3 | d4 d5 d6 d7] → [d4 d5 d6 d7 | d0 d1 d2 d3]
         let (lo, hi) = unit.split_at_mut(4);
         lo.swap_with_slice(hi);
@@ -742,8 +742,8 @@ pub fn detile(
     let bpb_log2 = (bpb as u32).trailing_zeros();
 
     // Visible dimensions in blocks, and the padded storage pitch/height.
-    let blocks_wide = ((width + block_size - 1) / block_size).max(1);
-    let blocks_tall = ((height + block_size - 1) / block_size).max(1);
+    let blocks_wide = width.div_ceil(block_size).max(1);
+    let blocks_tall = height.div_ceil(block_size).max(1);
     let pitch_aligned = align_up(blocks_wide, STORAGE_ALIGN_BLOCKS).max(MACRO_TILE_BLOCKS);
     let height_aligned = align_up(blocks_tall, STORAGE_ALIGN_BLOCKS).max(MACRO_TILE_BLOCKS);
 

crates/sylpheed-formats/src/ui_layout.rs

@@ -910,7 +910,7 @@ pub fn compose(
     // A dim backdrop stands in for the PRMD dim-quad + the live 3D scene behind
     // an in-mission screen.
     let mut canvas = vec![0u8; (w as usize) * (h as usize) * 4];
-    for px in canvas.chunks_exact_mut(4) {
+    for px in canvas.as_chunks_mut::<4>().0 {
         px.copy_from_slice(&opts.backdrop);
     }
     let mut drawn = Vec::new();

crates/sylpheed-formats/src/vfs.rs

@@ -237,7 +237,7 @@ pub fn decode_text(bytes: &[u8]) -> (String, &'static str) {
 
 fn decode_utf16(bytes: &[u8], big_endian: bool) -> String {
     let units: Vec<u16> = bytes
-        .chunks_exact(2)
+        .as_chunks::<2>().0.iter()
         .map(|c| {
             if big_endian {
                 u16::from_be_bytes([c[0], c[1]])

crates/sylpheed-formats/src/xiso.rs

@@ -53,7 +53,7 @@ impl<F: Read + Seek + Send + Sync + 'static> XisoReader<F> {
 
         info!(
             "Opened XISO: root directory table at sector {}",
-            { let s = volume.root_table.region.sector; s }
+            {  volume.root_table.region.sector }
         );
         Ok(Self { volume, file: wrapper })
     }

crates/sylpheed-viewer/src/asset_loader.rs

@@ -101,7 +101,7 @@ pub fn x360_texture_to_bevy_image(tex: X360Texture) -> Result<Image, Xpr2LoadErr
         X360TextureFormat::A8R8G8B8 | X360TextureFormat::X8R8G8B8 => {
             let opaque = matches!(tex.format, X360TextureFormat::X8R8G8B8);
             let mut out = tex.data;
-            for px in out.chunks_exact_mut(4) {
+            for px in out.as_chunks_mut::<4>().0 {
                 let (a, r, g, b) = (px[0], px[1], px[2], px[3]);
                 px[0] = r;
                 px[1] = g;

crates/sylpheed-viewer/src/iso_loader.rs

@@ -2035,6 +2035,10 @@ fn decode_audio_wav(video: &Path, wav: &Path) -> Result<(), String> {
 
 // ── Video decode + audio (main thread) ────────────────────────────────────────
 
+/// `(pts, rgba_bytes)` as the reader thread forwards them from `ffmpeg`.
+#[cfg(not(target_arch = "wasm32"))]
+type FrameRx = mpsc::Receiver<(f32, Vec<u8>)>;
+
 /// Spawn an `ffmpeg` process decoding to raw RGBA on stdout, plus a reader
 /// thread that chunks it into frames and forwards `(pts, bytes)` over a bounded
 /// channel. Optional `-ss start` seeks the input; output pts re-base to 0, so we
@@ -2046,7 +2050,7 @@ fn spawn_video_decoder(
     h: u32,
     fps: f32,
     start: f32,
-) -> Result<(Child, mpsc::Receiver<(f32, Vec<u8>)>), String> {
+) -> Result<(Child, FrameRx), String> {
     let mut cmd = Command::new("ffmpeg");
     cmd.arg("-v").arg("error");
     if start > 0.0 {
@@ -2177,6 +2181,12 @@ fn scrub_worker(
 
 /// Polls the mpsc channel, updating `IsoState`, `FileBrowserState`, and
 /// `PendingFileBytes` as messages arrive.
+// Bevy system: every parameter is a `Res`/`ResMut`/`EventWriter` the
+// scheduler injects. The count is the framework's dependency list, not a
+// signature anyone calls by hand, and it cannot be reduced without
+// bundling into a `SystemParam` struct. clippy's general heuristic does
+// not know about the idiom.
+#[allow(clippy::too_many_arguments)]
 #[cfg(not(target_arch = "wasm32"))]
 fn poll_loader_channel(
     channels: Res<IsoChannels>,
@@ -2557,7 +2567,7 @@ fn pick_albedo_index(model_name: &str, tex_names: &[String]) -> Option<usize> {
 #[cfg(not(target_arch = "wasm32"))]
 fn compute_smooth_normals(positions: &[[f32; 3]], indices: &[u32]) -> Vec<[f32; 3]> {
     let mut acc = vec![Vec3::ZERO; positions.len()];
-    for tri in indices.chunks_exact(3) {
+    for tri in indices.as_chunks::<3>().0 {
         let (a, b, c) = (tri[0] as usize, tri[1] as usize, tri[2] as usize);
         if a >= positions.len() || b >= positions.len() || c >= positions.len() {
             continue;
@@ -3106,7 +3116,7 @@ fn prepare_models_impl(
                     // Append the slice's triangles, re-emitting vertices per index
                     // (no dedup) so each material buffer stays self-contained. A
                     // reflected instance swaps two corners to keep front faces out.
-                    for tri in sub.indices[(*off).min(end)..end].chunks_exact(3) {
+                    for tri in sub.indices[(*off).min(end)..end].as_chunks::<3>().0 {
                         let corners = if reflect {
                             [tri[0], tri[2], tri[1]]
                         } else {
@@ -3405,6 +3415,12 @@ fn apply_prepared_xpr(
 
 /// Consumes a staged pack, freeing the previous texture/text previews and
 /// populating `PakView` for the master-detail browser.
+// Bevy system: every parameter is a `Res`/`ResMut`/`EventWriter` the
+// scheduler injects. The count is the framework's dependency list, not a
+// signature anyone calls by hand, and it cannot be reduced without
+// bundling into a `SystemParam` struct. clippy's general heuristic does
+// not know about the idiom.
+#[allow(clippy::too_many_arguments)]
 #[cfg(not(target_arch = "wasm32"))]
 fn apply_pak(
     mut pending: ResMut<PendingPak>,
@@ -4076,7 +4092,7 @@ fn build_game_snapshot(source: &SourceKind) -> Option<GameSnapshot> {
             Some(CharRow { name, faction: c.faction.unwrap_or_default(), faces: c.faces.len() })
         })
         .collect();
-    characters.sort_by(|a, b| (a.faction.clone(), a.name.clone()).cmp(&(b.faction.clone(), b.name.clone())));
+    characters.sort_by_key(|a| (a.faction.clone(), a.name.clone()));
 
     // Combat rosters, keyed by stage where the table self-identifies.
     let rosters = gd::load_unit_rosters(&main);
@@ -4742,7 +4758,7 @@ fn build_ship_model(
                 *nrm = rot(&p.m, nrm);
             }
             if det < 0.0 {
-                for tri in sub.indices.chunks_exact_mut(3) {
+                for tri in sub.indices.as_chunks_mut::<3>().0 {
                     tri.swap(1, 2);
                 }
             }
@@ -4911,7 +4927,7 @@ fn handle_cutscene_cues_request(
         // The naming convention is the obvious route and it is wrong often
         // enough to matter -- resolving the region is the only reading that
         // yields the right audio.
-        let voice = (|| {
+        let voice = {
             use sylpheed_formats::{hash::name_hash, media, PakArchive};
             let vlang = match lang.pak_code() {
                 "jpn" => sylpheed_formats::slb::VoiceLang::Japanese,
@@ -4934,7 +4950,7 @@ fn handle_cutscene_cues_request(
                 named_range,
                 region,
             })
-        })();
+        };
 
         let _ = sender.send(IsoLoaderMsg::CutsceneCuesLoaded {
             generation,

crates/sylpheed-viewer/src/lib.rs

@@ -50,7 +50,7 @@ pub fn run() {
         DefaultPlugins.set(WindowPlugin {
             primary_window: Some(Window {
                 title: "Project Sylpheed: Arc of Deception — Asset Viewer".into(),
-                resolution: (1280.0, 720.0).into(),
+                resolution: (1280.0_f32, 720.0_f32).into(),
                 ..default()
             }),
             ..default()

crates/sylpheed-viewer/src/ui.rs

@@ -157,6 +157,12 @@ struct UiEvents<'w> {
     cutscenes: EventWriter<'w, RequestCutscenes>,
 }
 
+// Bevy system: every parameter is a `Res`/`ResMut`/`EventWriter` the
+// scheduler injects. The count is the framework's dependency list, not a
+// signature anyone calls by hand, and it cannot be reduced without
+// bundling into a `SystemParam` struct. clippy's general heuristic does
+// not know about the idiom.
+#[allow(clippy::too_many_arguments)]
 fn draw_viewer_ui(
     mut contexts: EguiContexts,
     mut viewer: ResMut<ViewerState>,
@@ -656,7 +662,7 @@ fn draw_viewer_ui(
                     ui.strong("Notes");
                     ui.end_row();
 
-                    let mut row = |ui: &mut egui::Ui, fmt: &str, c, status: &str, notes: &str| {
+                    let row = |ui: &mut egui::Ui, fmt: &str, c, status: &str, notes: &str| {
                         ui.label(fmt);
                         ui.colored_label(c, status);
                         ui.label(notes);
@@ -1236,7 +1242,7 @@ fn draw_video_player(
         // Subtitle + voice controls (right-aligned): language, CC, and Voice.
         ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
             let before = subs.lang;
-            egui::ComboBox::from_id_source("subtitle_lang")
+            egui::ComboBox::from_id_salt("subtitle_lang")
                 .selected_text(subs.lang.label())
                 .show_ui(ui, |ui| {
                     for lang in SubLang::ALL {

docs/agents/PROTOCOL.md

@@ -167,7 +167,7 @@ neither its own branch nor `main`.
 
 ## Checks that were kind once
 
-Two rules that look unrelated and are the same failure.
+Three instances now, and they are the same failure.
 
 **A check may only soften against a condition it can test.**
 
@@ -189,6 +189,45 @@ a collaborator exists, so the "yet" was never needed.
 stays. That is why they survive review, and why the smell is worth naming:
 *leniency with an expiry date nobody set.*
 
+### The third instance was authored dirty, not decayed into
+
+The two above were **correct when written**. The third was not, and it is worth
+separating because it arrives by a different route and is caught at a different
+moment.
+
+CI's `Clippy` step turned out never to have run — the toolchain shipped without
+the component, so `cargo clippy -- -D warnings` died on *"not installed"* on
+every commit in the repo's history. Fixing that is two lines. But the tree is
+not clippy-clean: the build already emits ~13 rustc warnings that `-D warnings`
+promotes to errors. So the fix and the first red result arrive together, and the
+first draft paired the two-line fix with `continue-on-error: true` and a comment
+saying *delete this line once the debt is paid* — which is precisely an expiry
+date nobody set. It was reverted within the hour, on reading #12's own closing
+line ruling the same shape out for rustfmt.
+
+The difference that matters:
+
+| | first two | third |
+|---|---|---|
+| when it was wrong | became wrong later | wrong on the first commit |
+| what caused it | the world moved | the tree was already dirty |
+| what catches it | auditing old allowances | noticing the impulse at the keyboard |
+
+**This is the default way a check gets written when the tree is not clean yet.**
+Not a rare slip — the ordinary shape of the first draft. Whenever a real check
+goes in against a tree that does not yet pass it, the softening is *right there*,
+it looks like pragmatism, and it comes with a sincere comment promising removal.
+The mechanical test still catches it after the fact. The earlier tell is this:
+
+> **If you are writing the softening in the same commit as the check, the thing
+> you want is an issue, not a flag.**
+
+A red check that measures something is worth more than a green one that measures
+nothing, and it is worth strictly more than a green one that *used to* measure
+something. Land the check gating, let it be red, and scope the debt where it can
+be read, argued with and closed — #12 for rustfmt, #13 for clippy. An issue has
+the expiry date the flag never gets.
+
 `share put <file> --note "…" --for port` records the sender, the time, **the
 commit they were on**, and whether their tree was dirty. A capture with no
 provenance is not evidence, it is a picture.