feat: v0.22.0 — edition 2024 modernization + layout/render perf + honest lightness docs

.github/workflows/ci.yml

@@ -20,13 +20,13 @@ jobs:
       - run: cargo check --all-features
 
   check-msrv:
-    name: Check (MSRV 1.81)
+    name: Check (MSRV 1.88)
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: "1.81"
+          toolchain: "1.88"
       - uses: Swatinem/rust-cache@v2
       - run: cargo generate-lockfile
       - run: cargo check --features async,serde

.github/workflows/release.yml

@@ -29,13 +29,13 @@ jobs:
       - run: cargo fmt -- --check
 
   ci-msrv:
-    name: CI Gate (MSRV 1.81)
+    name: CI Gate (MSRV 1.88)
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: "1.81"
+          toolchain: "1.88"
       - uses: Swatinem/rust-cache@v2
       - run: cargo generate-lockfile
       - run: cargo check --features async,serde

AGENTS.md

@@ -125,7 +125,7 @@ cargo deny check
 |-----|---------|---------------|
 | Format | `cargo fmt -- --check` | Yes |
 | Check (stable) | `cargo check --all-features` | Yes |
-| Check (MSRV 1.81) | `cargo check --features async,serde` (toolchain 1.81) | Yes |
+| Check (MSRV 1.88) | `cargo check --features async,serde` (toolchain 1.88) | Yes |
 | Clippy | `cargo clippy --all-features -- -D warnings` | Yes |
 | Test | `cargo test --all-features` | Yes |
 | Typos | `typos` | Yes |

CHANGELOG.md

@@ -1,5 +1,112 @@
 # Changelog
 
+## [0.22.0] - 2026-06-11
+
+Rust modernization and optimization release. No new public widgets or features —
+this cycle migrates the crate to the 2024 edition, adopts let-chains across the
+core, tightens the lint posture, removes a dead dependency, memoizes layout
+intrinsic sizing, and fixes a measured rendering regression. The public API
+surface is unchanged.
+
+### Changed
+
+- **Edition 2024** — both `superlighttui` and `slt-wasm` now build on the 2024
+  edition.
+- **MSRV 1.85 → 1.88** — the core adopts let-chains (`if let … && let …`,
+  flattening ~50 nested if-let sites across the codebase), stabilized in Rust
+  1.88.0. The CI MSRV gate and docs are pinned to 1.88 accordingly. (MSRV bumps
+  are permitted in minor releases per the MSRV policy.)
+- **Workspace lints** — shared `[workspace.lints]` config (`rust_2018_idioms`,
+  rustdoc broken/private intra-doc links), opted into by both packages via
+  `[lints] workspace = true`. Library-only hygiene lints (`missing_docs`,
+  `unreachable_pub`, clippy `unwrap_in_result`/`unwrap_used`/`dbg_macro`/
+  `print_stdout`/`print_stderr`, and the cfg-conditional `unsafe_code` policy)
+  stay as lib-target inner attributes in both `lib.rs` files, since `[lints]`
+  is package-scoped and would otherwise fire on examples and integration tests.
+  `cargo clippy --all-features --all-targets -- -D warnings` is now clean.
+- **`unicode-segmentation` bound relaxed** — `>=1.0, <1.13` → `1`; the upper
+  bound only existed to keep the dropped 1.81 MSRV gate green.
+- **Error impls on `core::error::Error`** — `ColorParseError` and
+  `ThemeLoadError` now implement `core::error::Error` (drop-in; `std::error::
+  Error` is the same trait re-exported).
+- **`OnceLock` → `LazyLock`** where initialization is a plain constant
+  (`SEP_LINE`); fallible tree-sitter configs stay on `OnceLock`.
+
+### Removed
+
+- **`indexmap` direct dependency** — it had zero uses in `src/`; the manifest
+  entry existed only as an MSRV-compatibility version pin for the transitive
+  copy pulled by `toml` (`serde`/`theme-watch` features). Resolved dependency
+  tree shrinks from 13 → 10 crates with `default-features = false` and
+  28 → 25 with default features (vs 68 for a ratatui + crossterm app).
+
+### Fixed
+
+- **Startup deadlock on terminals that never answer capability probes** — the
+  DA1/DA2, Kitty-graphics, XTGETTCAP, DECRQM, and OSC reply readers gated a
+  blocking `stdin` read behind `crossterm::event::poll()`, which reports
+  crossterm's *internal event queue*, not raw-descriptor readability — and
+  crossterm's poller consumes bytes from the same descriptor. On hosts that
+  answer nothing (detached tmux panes, `script`/CI PTY wrappers), applications
+  hung forever on a blank alternate screen before the first frame, and typed
+  keys were swallowed instead of unblocking the read. Replies are now pumped
+  through a dedicated reader thread and awaited with `recv_timeout`, so every
+  probe is hard-bounded by its documented budget (≤180 ms total at startup)
+  regardless of host behavior. Residual on fully silent hosts: the parked
+  reader can swallow at most one byte of typeahead — bounded, versus the
+  previous unbounded hang. Affects `run()` startup, `detect_color_scheme`,
+  `read_clipboard`, and the Kitty cell-size query.
+
+### Perf
+
+- **Layout intrinsic-size memoization** — `min_width` / `min_height` /
+  `min_height_for_width` recursed over the entire subtree at every ancestor
+  level each frame (O(nodes × depth)). They are now memoized per node per
+  frame via `Cell` fields on `LayoutNode`, invalidated at the
+  `resolve_axis_specs` points (row and column passes) where a Pct/Ratio
+  constraint resolves mid-layout.
+  Output is byte-identical (regression tests + full proptest suite); a new
+  `layout_deep_tree_120x40` bench (14-level nested panels) tracks the
+  asymptotic win.
+- **`dim_buffer_around` / `dim_entire_buffer` rewrite** — the modal dimming
+  strips now OR the `DIM` modifier over contiguous buffer-row slices instead
+  of per-cell `get_mut` with bounds asserts. All `v020_perf_audit` dim arms
+  improved (small modal 61.9 → 53.5 µs, large modal 59.2 → 48.2 µs, full scan
+  106.4 → 55.0 µs at 200×60 on the reference machine), fixing a measured
+  regression from the original strip optimization (#228).
+- Audited the double-buffer line-hash path for redundant re-hashing of the
+  previous buffer: the existing `line_dirty` tracking already makes the second
+  `recompute_line_hashes` call near-free in steady state (verified by
+  `flush/static_200x60` at ~114 ns); no change needed.
+
+### Docs
+
+- **Lightness claims corrected to measured reality** — the "Dependencies: 2"
+  claim in `COMPETITIVE_ANALYSIS.md` was false and is replaced with measured
+  numbers (4 direct required deps; 25 resolved with default features vs 68 for
+  ratatui + crossterm). README taglines (all languages), `FEATURES.md`, and
+  `DESIGN_PRINCIPLES.md` now frame "light" as dependency footprint + API
+  surface, and explicitly do not claim a smaller stripped binary (a minimal
+  SLT hello is ~1.45× ratatui's) or faster cold build.
+- **docs.rs feature badges** — 36 `#[cfg_attr(docsrs, doc(cfg(feature =
+  "…")))]` annotations added so every public feature-gated item (entry points,
+  `PtyBackend`, `TaskHandle`, `ThemeWatcher`, syntax/image/qrcode widgets, …)
+  shows its required feature on docs.rs.
+- `#[must_use]` added to `ThemeBuilder` and `EventBuilder` (the remaining
+  builders and `Response` already carried it).
+
+### Internal
+
+- Edition-2024 fallout: `std::env::set_var` is now `unsafe`, so the
+  `#![forbid(unsafe_code)]` policy became cfg-conditional — `forbid` for every
+  shipping build, `deny` with two audited, mutex-serialized exemptions in
+  `#[cfg(test)]` env helpers. The published library remains 100% safe code.
+- RPIT precise-capture (`+ use<>`) on `Rect::rows()` / `Rect::positions()`;
+  `expr_2021` → `expr` macro fragment in the internal `flush_run!` macro.
+- 17 never-public `Terminal` / `InlineTerminal` / `KittyImageManager` /
+  `SelectionState` methods downgraded `pub` → `pub(crate)` (flagged by
+  `unreachable_pub`; none were reachable outside the crate).
+
 ## [0.21.1] - 2026-05-30
 
 Interaction-signal completeness, API ergonomics, WASM parity, perf, and

CONTRIBUTING.md

@@ -124,7 +124,7 @@ git push --tags
 ```
 
 The release workflow (`.github/workflows/release.yml`) will:
-1. Run full CI (check, test, clippy, fmt) on stable + MSRV 1.81
+1. Run full CI (check, test, clippy, fmt) on stable + MSRV 1.88
 2. Verify tag matches `Cargo.toml` version
 3. Publish to crates.io
 4. Create GitHub Release with notes extracted from CHANGELOG.md

Cargo.toml

@@ -1,10 +1,30 @@
 [workspace]
 members = [".", "crates/slt-wasm"]
 
+# Shared lint configuration applied to every workspace member via
+# `[lints] workspace = true`. NOTE: `[lints]` is package-scoped, so these
+# apply to ALL targets in a package (lib, examples, benches, tests), not just
+# the library. Library-API hygiene lints are therefore deliberately NOT listed
+# here and stay as lib-only inner attributes in src/lib.rs (mirrored in
+# crates/slt-wasm/src/lib.rs): `missing_docs`, `unreachable_pub`, and the
+# clippy unwrap/print/dbg family — example binaries and integration tests
+# legitimately print to stdout and unwrap, so package-wide enforcement would
+# flood them with warnings. The cfg-conditional `unsafe_code` policy (forbid
+# in shipping builds, deny under #[cfg(test)] because edition 2024 made env
+# mutation unsafe) likewise cannot be expressed here and stays in src/lib.rs.
+[workspace.lints.rust]
+# rust-2018-idioms is a lint group; priority -1 lets individual lints below
+# override members of the group if needed.
+rust_2018_idioms = { level = "warn", priority = -1 }
+
+[workspace.lints.rustdoc]
+broken_intra_doc_links = "warn"
+private_intra_doc_links = "warn"
+
 [package]
 name = "superlighttui"
-version = "0.21.1"
-edition = "2021"
+version = "0.22.0"
+edition = "2024"
 description = "Super Light TUI - A lightweight, ergonomic terminal UI library"
 license = "MIT"
 repository = "https://github.com/subinium/SuperLightTUI"
@@ -13,7 +33,9 @@ documentation = "https://docs.rs/superlighttui"
 readme = "README.md"
 keywords = ["tui", "terminal", "cli", "ui", "immediate-mode"]
 categories = ["command-line-interface"]
-rust-version = "1.81"
+# let-chains (`if let … && let …`) used across the core were stabilized in
+# Rust 1.88.0; edition 2024 alone (1.85) is not enough. MSRV is therefore 1.88.
+rust-version = "1.88"
 # Keep the published crate to library + docs only. The agent/skill scaffolding,
 # VHS recordings, and dev/CI config are not needed by downstream consumers
 # (they were leaking into 0.21.0's tarball — ~140KB of non-library content).
@@ -41,20 +63,17 @@ exclude = [
 # v0.20 release notes for why these were merged into tours.
 autoexamples = false
 
+[lints]
+workspace = true
+
 [lib]
 name = "slt"
 
 [dependencies]
 crossterm = { version = "0.28", features = ["bracketed-paste"], optional = true }
 unicode-width = "0.2"
-# Upper-bounded for MSRV 1.81: unicode-segmentation 1.13+ requires rustc 1.85.
-unicode-segmentation = ">=1.0, <1.13"
+unicode-segmentation = "1"
 smallvec = "1"
-# MSRV 1.81 pin only (not used directly): a transitive dep via `toml`
-# (the `serde`/`theme-watch` features). indexmap 2.10+ requires the
-# `edition2024` Cargo feature (rustc 1.85), which breaks the MSRV gate's
-# `cargo generate-lockfile` + 1.81 check. Bound it below that.
-indexmap = ">=2.0, <2.10"
 tokio = { version = "1", features = ["rt", "sync", "macros", "time"], optional = true }
 serde = { version = "1", features = ["derive"], optional = true }
 toml = { version = "0.8", optional = true }

README.md

@@ -2,7 +2,7 @@
 
 # SuperLightTUI
 
-**Superfast** to write. **Superlight** to run.
+**Superfast** to write. **Superlight** dependency tree (4 direct required deps, 25 resolved with default features vs 68 for ratatui + crossterm).
 
 [![Crate Badge]][Crate]
 [![Docs Badge]][Docs]
@@ -57,7 +57,7 @@ fn main() -> std::io::Result<()> {
 
 5 lines. No `App` trait. No `Model`/`Update`/`View`. No manual event loop. Ctrl+C just works.
 
-MSRV: Rust 1.81. Default features enable the `crossterm` backend.
+MSRV: Rust 1.88. Default features enable the `crossterm` backend.
 
 ## 60-Second Grammar