codex

feat(tui): syntax highlighting via syntect with theme picker (#11447 )

## Summary

Adds syntax highlighting to the TUI for fenced code blocks in markdown
responses and file diffs, plus a `/theme` command with live preview and
persistent theme selection. Uses syntect (~250 grammars, 32 bundled
themes, ~1 MB binary cost) — the same engine behind `bat`, `delta`, and
`xi-editor`. Includes guardrails for large inputs, graceful fallback to
plain text, and SSH-aware clipboard integration for the `/copy` command.

<img width="1554" height="1014" alt="image"
src="https://github.com/user-attachments/assets/38737a79-8717-4715-b857-94cf1ba59b85"
/>

<img width="2354" height="1374" alt="image"
src="https://github.com/user-attachments/assets/25d30a00-c487-4af8-9cb6-63b0695a4be7"
/>

## Problem

Code blocks in the TUI (markdown responses and file diffs) render
without syntax highlighting, making it hard to scan code at a glance.
Users also have no way to pick a color theme that matches their terminal
aesthetic.

## Mental model

The highlighting system has three layers:

1. **Syntax engine** (`render::highlight`) -- a thin wrapper around
syntect + two-face. It owns a process-global `SyntaxSet` (~250 grammars)
and a `RwLock<Theme>` that can be swapped at runtime. All public entry
points accept `(code, lang)` and return ratatui `Span`/`Line` vectors or
`None` when the language is unrecognized or the input exceeds safety
guardrails.

2. **Rendering consumers** -- `markdown_render` feeds fenced code blocks
through the engine; `diff_render` highlights Add/Delete content as a
whole file and Update hunks per-hunk (preserving parser state across
hunk lines). Both callers fall back to plain unstyled text when the
engine returns `None`.

3. **Theme lifecycle** -- at startup the config's `tui.theme` is
resolved to a syntect `Theme` via `set_theme_override`. At runtime the
`/theme` picker calls `set_syntax_theme` to swap themes live; on cancel
it restores the snapshot taken at open. On confirm it persists `[tui]
theme = "..."` to config.toml.

## Non-goals

- Inline diff highlighting (word-level change detection within a line).
- Semantic / LSP-backed highlighting.
- Theme authoring tooling; users supply standard `.tmTheme` files.

## Tradeoffs

| Decision | Upside | Downside |
| ------------------------------------------------ |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
-----------------------------------------------------------------------------------------------------------------------
|
| syntect over tree-sitter / arborium | ~1 MB binary increase for ~250
grammars + 32 themes; battle-tested crate powering widely-used tools
(`bat`, `delta`, `xi-editor`). tree-sitter would add ~12 MB for 20-30
languages or ~35 MB for full coverage. | Regex-based; less structurally
accurate than tree-sitter for some languages (e.g. language injections
like JS-in-HTML). |
| Global `RwLock<Theme>` | Enables live `/theme` preview without
threading Theme through every call site | Lock contention risk
(mitigated: reads vastly outnumber writes, single UI thread) |
| Skip background / italic / underline from themes | Terminal BG
preserved, avoids ugly rendering on some themes | Themes that rely on
these properties lose fidelity |
| Guardrails: 512 KB / 10k lines | Prevents pathological stalls on huge
diffs or pastes | Very large files render without color |

## Architecture

```
config.toml  ─[tui.theme]─>  set_theme_override()  ─>  THEME (RwLock)
                                                              │
                  ┌───────────────────────────────────────────┘
                  │
  markdown_render ─── highlight_code_to_lines(code, lang) ─> Vec<Line>
  diff_render     ─── highlight_code_to_styled_spans(code, lang) ─> Option<Vec<Vec<Span>>>
                  │
                  │   (None ⇒ plain text fallback)
                  │
  /theme picker   ─── set_syntax_theme(theme)    // live preview swap
                  ─── current_syntax_theme()      // snapshot for cancel
                  ─── resolve_theme_by_name(name) // lookup by kebab-case
```

Key files:

- `tui/src/render/highlight.rs` -- engine, theme management, guardrails
- `tui/src/diff_render.rs` -- syntax-aware diff line wrapping
- `tui/src/theme_picker.rs` -- `/theme` command builder
- `tui/src/bottom_pane/list_selection_view.rs` -- side content panel,
callbacks
- `core/src/config/types.rs` -- `Tui::theme` field
- `core/src/config/edit.rs` -- `syntax_theme_edit()` helper

## Observability

- `tracing::warn` when a configured theme name cannot be resolved.
- `Config::startup_warnings` surfaces the same message as a TUI banner.
- `tracing::error` when persisting theme selection fails.

## Tests

- Unit tests in `highlight.rs`: language coverage, fallback behavior,
CRLF stripping, style conversion, guardrail enforcement, theme name
mapping exhaustiveness.
- Unit tests in `diff_render.rs`: snapshot gallery at multiple terminal
sizes (80x24, 94x35, 120x40), syntax-highlighted wrapping, large-diff
guardrail, rename-to-different-extension highlighting, parser state
preservation across hunk lines.
- Unit tests in `theme_picker.rs`: preview rendering (wide + narrow),
dim overlay on deletions, subtitle truncation, cancel-restore, fallback
for unavailable configured theme.
- Unit tests in `list_selection_view.rs`: side layout geometry, stacked
fallback, buffer clearing, cancel/selection-changed callbacks.
- Integration test in `lib.rs`: theme warning uses the final
(post-resume) config.

## Cargo Deny: Unmaintained Dependency Exceptions

This PR adds two `cargo deny` advisory exceptions for transitive
dependencies pulled in by `syntect v5.3.0`:

| Advisory | Crate | Status |
|----------|-------|--------|
| RUSTSEC-2024-0320 | `yaml-rust` | Unmaintained (maintainer
unreachable) |
| RUSTSEC-2025-0141 | `bincode` | Unmaintained (development ceased;
v1.3.3 considered complete) |

**Why this is safe in our usage:**

- Neither advisory describes a known security vulnerability. Both are
"unmaintained" notices only.
- `bincode` is used by syntect to deserialize pre-compiled syntax sets.
Again, these are **static vendored artifacts** baked into the binary at
build time. No user-supplied bincode data is ever deserialized. - Attack
surface is zero for both crates; exploitation would require a
supply-chain compromise of our own build artifacts.
- These exceptions can be removed when syntect migrates to `yaml-rust2`
and drops `bincode`, or when alternative crates are available upstream.

Felipe Coury · 2026-02-21 20:26:58 -08:00

c4f1af7a86

feat: enable premessage-deflate for websockets (#10966 )

note:
unfortunately, tokio-tungstenite / tungstenite upgrade triggers some
problems with linker of rama-tls-boring with openssl:
```
error: linking with `/Users/apanasenko/Library/Caches/cargo-zigbuild/0.20.1/zigcc-x86_64-unknown-linux-musl-ff6a.sh` failed: exit status: 1
  |
  = note:  "/Users/apanasenko/Library/Caches/cargo-zigbuild/0.20.1/zigcc-x86_64-unknown-linux-musl-ff6a.sh" "-m64" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/rcrt1.o" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/crti.o" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/crtbeginS.o" "<1 object files omitted>" "-Wl,--as-needed" "-Wl,-Bstatic" "/var/folders/kt/52y_g75x3ng8ktvk3rfwm6400000gp/T/rustcyGQdYm/{liblzma_sys-662a82316f96ec30,libbzip2_sys-bf78a2d58d5cbce6,liblibsqlite3_sys-6c004987fd67a36a,libtree_sitter_bash-220b99a97d331ab7,libtree_sitter-858f0a1dbfea58bd,libzstd_sys-6eb237deec748c5b,libring-2a87376483bf916f,libopenssl_sys-7c189e68b37fe2bb,liblibz_sys-4344eef4345520b1,librama_boring_sys-0414e98115015ee0}.rlib" "-lc++" "-lc++abi" "-lunwind" "-lc" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/libcompiler_builtins-*.rlib" "-L" "/var/folders/kt/52y_g75x3ng8ktvk3rfwm6400000gp/T/rustcyGQdYm/raw-dylibs" "-Wl,-Bdynamic" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-nostartfiles" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/libz-sys-ff5ea50d88c28ffb/out/lib" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/ring-bdec3dddc19f5a5e/out" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/openssl-sys-96e0870de3ca22bc/out/openssl-build/install/lib" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/zstd-sys-0cc37a5da1481740/out" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/tree-sitter-72d2418073317c0f/out" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/tree-sitter-bash-bfd293a9f333ce6a/out" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/libsqlite3-sys-b78b2cfb81a330fc/out" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/bzip2-sys-69a145cc859ef275/out/lib" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/lzma-sys-07e92d0b6baa6fd4/out" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/rama-boring-sys-0bc2dfbf669addc4/out/build/crypto/" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/rama-boring-sys-0bc2dfbf669addc4/out/build/ssl/" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/rama-boring-sys-0bc2dfbf669addc4/out/build/" "-L" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/rama-boring-sys-0bc2dfbf669addc4/out/build" "-L" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained" "-L" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib" "-o" "/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/deps/codex_network_proxy-d08268b863517761" "-Wl,--gc-sections" "-static-pie" "-Wl,-z,relro,-z,now" "-Wl,-O1" "-Wl,--strip-all" "-nodefaultlibs" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/crtendS.o" "<sysroot>/lib/rustlib/x86_64-unknown-linux-musl/lib/self-contained/crtn.o"
  = note: some arguments are omitted. use `--verbose` to show all linker arguments
  = note: warning: ignoring deprecated linker optimization setting '1'
          warning: unable to open library directory '/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/rama-boring-sys-0bc2dfbf669addc4/out/build/crypto/': FileNotFound
          ld.lld: error: duplicate symbol: SSL_export_keying_material
          >>> defined at ssl_lib.c:3816 (ssl/ssl_lib.c:3816)
          >>>            libssl-lib-ssl_lib.o:(SSL_export_keying_material) in archive /var/folders/kt/52y_g75x3ng8ktvk3rfwm6400000gp/T/rustcyGQdYm/libopenssl_sys-7c189e68b37fe2bb.rlib
          >>> defined at t1_enc.cc:205 (/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/rama-boring-sys-0bc2dfbf669addc4/out/boringssl/ssl/t1_enc.cc:205)
          >>>            t1_enc.cc.o:(.text.SSL_export_keying_material+0x0) in archive /var/folders/kt/52y_g75x3ng8ktvk3rfwm6400000gp/T/rustcyGQdYm/librama_boring_sys-0414e98115015ee0.rlib

          ld.lld: error: duplicate symbol: d2i_ASN1_TIME
          >>> defined at a_time.c:27 (crypto/asn1/a_time.c:27)
          >>>            libcrypto-lib-a_time.o:(d2i_ASN1_TIME) in archive /var/folders/kt/52y_g75x3ng8ktvk3rfwm6400000gp/T/rustcyGQdYm/libopenssl_sys-7c189e68b37fe2bb.rlib
          >>> defined at a_time.cc:34 (/Users/apanasenko/code/codex/codex-rs/target/x86_64-unknown-linux-musl/release/build/rama-boring-sys-0bc2dfbf669addc4/out/boringssl/crypto/asn1/a_time.cc:34)
          >>>            a_time.cc.o:(.text.d2i_ASN1_TIME+0x0) in archive /var/folders/kt/52y_g75x3ng8ktvk3rfwm6400000gp/T/rustcyGQdYm/librama_boring_sys-0414e98115015ee0.rlib
``` 

that force me to migrate away from rama-tls-boring to rama-tls-rustls
and pin `ring` for rustls.

Anton Panasenko · 2026-02-07 17:59:34 -08:00

a94505a92a

chore: update bytes crate in response to security advisory (#10525 )

While here, remove one advisory from `deny.toml` that has been addressed
(it was showing up as a warning).

Michael Bolin · 2026-02-03 17:08:04 +00:00

1634db6677

feat: introducing a network sandbox proxy (#8442 )

This add a new crate, `codex-network-proxy`, a local network proxy
service used by Codex to enforce fine-grained network policy (domain
allow/deny) and to surface blocked network events for interactive
approvals.

- New crate: `codex-rs/network-proxy/` (`codex-network-proxy` binary +
library)
- Core capabilities:
  - HTTP proxy support (including CONNECT tunneling)
  - SOCKS5 proxy support (in the later PR)
- policy evaluation (allowed/denied domain lists; denylist wins;
wildcard support)
  - small admin API for polling/reload/mode changes
- optional MITM support for HTTPS CONNECT to enforce “limited mode”
method restrictions (later PR)

Will follow up integration with codex in subsequent PRs.

## Testing

- `cd codex-rs && cargo build -p codex-network-proxy`
- `cd codex-rs && cargo run -p codex-network-proxy -- proxy`

viyatb-oai · 2026-01-23 17:47:09 -08:00

77222492f9

fix: upgrade lru crate to 0.16.3 (#8845 )

See https://rustsec.org/advisories/RUSTSEC-2026-0002.

Though our `ratatui` fork has a transitive dep on an older version of
the `lru` crate, so to get CI green ASAP, this PR also adds an exception
to `deny.toml` for `RUSTSEC-2026-0002`, but hopefully this will be
short-lived.

Michael Bolin · 2026-01-07 10:11:27 -08:00

a1e81180f8

chore: add cargo-deny configuration (#7119 )

- add GitHub workflow running cargo-deny on push/PR
- document cargo-deny allowlist with workspace-dep notes and advisory
ignores
- align workspace crates to inherit version/edition/license for
consistent checks

Josh McKinney · 2025-11-24 12:22:18 -08:00

ec49b56874

6 Commits