# Native theme migration plan

Integrate [`native-theme`](https://github.com/tiborgats/native-theme) (via the
`native-theme-gpui` connector) so the app follows the OS native theme on
macOS, Windows and Linux (KDE/GNOME), instead of only the bundled
`signed.json` themes.

Principles for this migration: plug the connector in, migrate what it
replaces, do not wrap it, and do not adopt its optional subsystems (icons,
theme-drawn widgets, presets UI) in this pass.

---

## 1. Current state

| Piece | Location | Notes |
| --- | --- | --- |
| Startup theme setup | `desktop/src/main.rs` | `gpui_component::init` + `theme::init`, loads `signed.json` into `ThemeRegistry`, sets `Theme::global_mut` fields (`radius`, `radius_lg`, `focus_ring`, `shadow`, `font_size`, `mono_font_size`, `light_theme`, `dark_theme`), then `Theme::change` / `Theme::sync_system_appearance` |
| Runtime theme application | `crates/workspace/src/views/sidebar/settings_dialog.rs` | `apply_theme()` re-reads settings into the global `Theme`; `apply_appearance()` maps `AppearanceMode` to `Theme::change` / `sync_system_appearance` |
| System appearance follow | `crates/workspace/src/workspace.rs` | `cx.observe_window_appearance` → `Theme::sync_system_appearance` when appearance is `System` |
| Theme settings | `crates/settings/src/settings.rs` (`ThemeSettings`) | `light_theme`, `dark_theme`, `font_size`, `mono_font_size`, `radius`, `radius_lg`, `focus_ring`, `shadow` |
| Bundled themes | `crates/assets/assets/themes/signed.json` | `Signed Light` / `Signed Dark` colors + a `highlight` section (editor/syntax colors) |
| Theme consumers | `dock`, `signed_ui`, `workspace` | ~50 `cx.theme()` call sites via `gpui_component::ActiveTheme` |

Dependencies today (branch `feat/native-theme`, commit `eb4fbb0`):
`gpui-pre` 0.3.9, `gpui-pre-platform` 0.3.9, `gpui-component` 0.8,
`gpui-base` 0.8, toolchain 1.96.

## 2. What the connector does

`native-theme-gpui` turns a `native_theme::ResolvedTheme` (read from the OS,
or from a bundled preset) into a fully configured `gpui_component::Theme` and
installs it:

- all 139 `ThemeColor` fields, fonts, `radius`, `shadow`, `focus_ring`,
  scrollbar and base-layer values;
- a `ThemeConfig` per mode, so the app's existing
  `Theme::change(mode, None, cx)` / `Theme::sync_system_appearance(..)`
  switch between the native light and dark palettes unchanged;
- an internal observer that restores the native values gpui-component
  overwrites on each rebuild;
- accessibility: the OS text-scaling factor scales fonts (through the window
  rem), reduce-motion and reduce-transparency are forwarded.

Because the connector produces a regular gpui-component `Theme`, every
existing `cx.theme()` call site keeps working without modification. That is
the core reason this integration is small.

Key APIs: `SystemTheme::from_system()`, `apply_system_theme(&system, cx)`,
`apply(theme, &resolved, &prefs, cx)`, `from_preset(name, is_dark, &prefs)`,
`AccessibilityPreferences::from_system()`.

## 3. Gate 0 — version compatibility (blocking)

Verified against crates.io and the upstream repo on 2026-10-21:

| Fact | Value |
| --- | --- |
| Latest connector | `native-theme-gpui` 0.6.1 (2026-10-09); upstream `main` is the same |
| Connector requires | `gpui-component ^0.7.1`, `gpui-base ^0.7.1`, `gpui-pre ^0.3.8`, Rust ≥ 1.95 |
| `gpui-component` 0.7.x pins | `gpui-pre =0.3.8` |
| `gpui-component` 0.8.0 pins | `gpui-pre =0.3.9` (0.8.0 published 2026-10-19) |
| This branch | moved 0.7.1 / 0.3.8 → 0.8 / 0.3.9 in `eb4fbb0` ("chore: update deps") |

The pins are mutually exclusive: with the app on `gpui-component` 0.8, cargo
cannot unify the graph — the connector would pull a second `gpui-pre` 0.3.8
and a second `gpui-component` 0.7.x, and `apply(.., cx)` would not even
type-check against the app's `App`. **The connector cannot be added on top of
gpui-component 0.8 today.**

### Decision

Revert the GPUI-side dependency bump on this branch and align with the
connector's supported closure (recommended):

```toml
# [workspace.dependencies]
gpui = { package = "gpui-pre", version = "0.3.8" }
gpui_platform = { package = "gpui-pre-platform", version = "0.3.8", features = ["font-kit", "x11", "wayland"] }
reqwest_client = { package = "gpui-pre-reqwest-client", version = "0.3.8" }

gpui-component = { version = "0.7.1", features = ["tree-sitter-languages"] }
gpui-base = "0.7.1"

native-theme = "0.6.1"
native-theme-gpui = "0.6.1"
```

- This is exactly the state of `master` before `eb4fbb0`, which is also the
  version set the connector was verified against (2026-10-08 stamp) and that
  its nightly dependency canary exercises. `"0.7.1"` is a caret requirement;
  it resolves the newest 0.7.x (currently 0.7.3). Pin `=0.7.1` instead if
  strict reproducibility is preferred.
- The three `gpui-pre-*` family crates are published in lockstep; all three
  move back to 0.3.8 together.
- The cost of the revert is the two one-line tweaks `eb4fbb0` made for 0.8
  (the `Deref` removal in `crates/dock/src/dock_area.rs`; verify it compiles
  either way). The nostr changes in that commit are unrelated and stay.
- When `native-theme-gpui` releases gpui-component 0.8 support (upstream has
  bumped within days of each gpui-component release so far), bump both sides
  together in one commit.

Alternative, rejected for now: staying on gpui-component 0.8 and waiting for
upstream 0.8 support. Nothing in this migration depends on 0.8-only APIs, and
0.8.0 shipped two days before this plan, so the revert is the cheaper path.

Note: the connector's README quick-start shows the `gpui-kit` facade crate;
this project depends on `gpui-component` + `gpui-base` directly, which is
equivalent — no `gpui-kit` dependency is needed.

## 4. Target design

### 4.1 Theme source

The native OS theme becomes the primary source. The bundled `signed.json`
registry stays as the fallback when the OS theme cannot be read (unsupported
Linux desktop, headless, etc.). This keeps the existing startup code as the
fallback branch instead of deleting a working safety net.

### 4.2 Startup flow (`desktop/src/main.rs`)

Order is load-bearing:

1. `gpui_component::init(cx)` and `theme::init(cx)` — must run before
   `apply` (connector requirement).
2. `SettingsStore` load — already before any theme work.
3. `ThemeRegistry` load from `Assets.themes()` — kept, feeds the fallback.
4. Apply the native theme:

```rust
let prefs = native_theme_gpui::AccessibilityPreferences::from_system();
match native_theme::SystemTheme::from_system() {
    Ok(system) => native_theme_gpui::apply_system_theme(&system, cx),
    Err(error) => {
        tracing::warn!("native theme unavailable ({error}); using bundled themes");
        // existing path: registry lookups + Theme::global_mut field setup
    }
}
// shared: the existing `match settings.appearance { .. }` block stays,
// now driving native palettes per mode on the native path.
```

`apply_system_theme` installs both the light and dark variants plus their
configs, so the subsequent `Theme::change` / `sync_system_appearance` for the
user's `AppearanceMode` picks the right native palette.

On the native path, do **not** set `radius` / `font_size` / `light_theme` /
`dark_theme` etc. on `Theme::global_mut` — the connector owns those fields,
and overwriting them fights its observer.

### 4.3 Appearance switching (no changes)

- `AppearanceMode::System | Light | Dark` and `apply_appearance()` in
  `settings_dialog.rs` work as-is.
- `workspace.rs`'s `observe_window_appearance` → `sync_system_appearance`
  keeps following the OS while in `System` mode.
- `Theme::change(mode, None, cx)` reproduces the native palette for the mode
  because the connector installed a `ThemeConfig` per variant.

Known gap (not addressed here): gpui-component's system-appearance follow is
driven by window-activation events. A live OS theme change while the window
is focused may not propagate on Linux until the window is re-focused;
native-theme's `watch` feature (a theme-change watcher) is a possible
follow-up, out of scope.

### 4.4 Settings dialog (`settings_dialog.rs`)

Keep:

- the **Appearance** row (`System` / `Light` / `Dark`) and its handler.

Remove (the native theme now owns all of these):

- **Light Theme** / **Dark Theme** pickers and `theme_options()` — colors are
  chosen by the OS. This is also the only way to avoid the connector's
  registry trap: selecting a registry theme would overwrite the connector's
  per-mode configs on the next `Theme::change` and silently drop native
  colors until restart.
- **Font size**, **Mono font size**, **Radius**, **Large radius**,
  **Focus ring**, **Shadows** rows and their handlers — the resolved theme
  provides geometry, and the connector already scales fonts by the OS text
  size. Keeping manual overrides would require re-applying them after every
  upstream rebuild, a permanent fight with the connector.

`apply_theme()` shrinks to the fallback-only body (registry lookups + global
field setup), called only when native detection failed at startup and by the
Appearance handler's fallback branch.

`ThemeSettings` keeps its fields and serde shape — the fallback branch still
reads them, existing settings files keep parsing, and the tests in
`settings.rs` stay valid. They become fallback-only tuning (editable via
`settings.json`). Deleting the fields is a possible follow-up cleanup if the
fallback ever moves to native-theme presets.

### 4.5 Syntax highlighting (known trade-off)

`signed.json` carries a `highlight` section (editor and syntax colors) used by
code and markdown rendering (`TextView` in the files view and elsewhere). The
connector's installed per-mode configs carry upstream's default highlighter
styles, so on the native path the active syntax palette is upstream's, not
Signed's.

Decision for this pass: accept upstream's defaults — zero code. If the Signed
syntax palette must be kept later, investigate whether gpui-component 0.7
exposes a syntax-theme setter that survives `Theme::change`; do not build an
override mechanism now.

### 4.6 Features

Use the connector with narrowed features; the app uses its own SVG icons and
gpui-component widgets:

```toml
native-theme-gpui = { version = "0.6.1", default-features = false, features = ["system-fonts"] }
```

`system-fonts` keeps a theme font family the system lacks drawing in the
platform's substitute. `widgets` (theme-drawn checkbox/switch/etc.),
`material-icons`, `lucide-icons`, `system-icons`, `svg-rasterize` are all
unused here and each carries build weight (the icon bundles are ~2 MB).
Adopting any of them is a separate, deliberate follow-up.

## 5. Change list

| File | Change |
| --- | --- |
| `Cargo.toml` | Revert gpui-side pins to 0.3.8 / 0.7.1 (Gate 0); add `native-theme` and `native-theme-gpui` workspace deps |
| `desktop/Cargo.toml` | Add `native-theme`, `native-theme-gpui` |
| `desktop/src/main.rs` | Native apply with bundled fallback (§4.2); move the settings-field setup into the fallback branch |
| `crates/workspace/src/views/sidebar/settings_dialog.rs` | Remove theme picker + font/radius/focus/shadow rows; shrink `apply_theme` to fallback-only (§4.4) |
| `CHANGELOG.md` | Added: native OS theme via `native-theme`; Removed: manual theme/font/radius settings |

Unchanged:

- every `cx.theme()` consumer in `dock`, `signed_ui`, `workspace` — including
  the dock/tab skins and window controls, which keep reading tokens;
- `crates/workspace/src/workspace.rs` appearance observer;
- `crates/settings` (fields stay), `crates/assets` (`signed.json` stays as
  the fallback), `crates/dock`.

## 6. Validation

1. `cargo check`, `cargo test`, `cargo clippy` across the workspace (toolchain
   1.96 satisfies the connector's 1.95 MSRV).
2. Manual matrix, per platform available (macOS first; KDE and GNOME Linux;
   Windows):
   - cold start matches the OS theme and accent; radius, fonts and controls
     read as native;
   - switching Appearance `System ↔ Light ↔ Dark` in settings switches native
     palettes;
   - with `System`, changing the OS theme and re-focusing the window updates
     the app;
   - settings dialog, dock tabs, diffs, files view, markdown rendering look
     correct; the syntax palette difference from §4.5 is reviewed and
     accepted;
   - `cargo run` once with native detection forced to fail (e.g. temporarily
     return early in the match) to prove the bundled fallback still works.
3. `cargo tree -i gpui-pre` and `cargo tree -i gpui-component` must each show
   exactly one version — the whole point of Gate 0.

## 7. Explicitly out of scope

- native-theme icon sets / `CustomIconName` mapping — the app keeps its own
  SVG assets.
- theme-drawn widgets (`widgets` feature).
- a preset-picker UI (`from_preset`) in settings.
- runtime OS-theme watching (`watch` feature).
- per-field user overrides layered on the native theme.
- migrating `signed.json` into a native-theme `Theme` definition.