fix: make file browser selection stateless and add browser regression coverage

README.md

@@ -47,7 +47,7 @@ Global shortcuts:
 - `J` or `ArrowDown`: scroll the active file view down one line when the file tree is hidden
 - `K` or `ArrowUp`: scroll the active file view up one line when the file tree is hidden
 - `Shift+L`: toggle file tree
-- `Y`: copy the current file's absolute path
+- `Y`: copy the current file's absolute path when the file tree is hidden
 - `R`: reload the current file
 - `Shift+T`: toggle table of contents for Markdown
 - `Shift+P`: switch Markdown raw/preview pane
@@ -69,6 +69,7 @@ File tree shortcuts:
 - `S`: sort by size descending
 - `H` or `ArrowLeft`: go to parent directory
 - `L`, `ArrowRight`, `Enter`: open or confirm selection
+- `Y`: copy the selected file or directory absolute path, or the current directory path when no row is selected
 - `Ctrl+M`: same as `Enter` in the filter field
 
 Video preview:
@@ -129,6 +130,17 @@ The repository is set up for `nix develop`, which provides Bun, Cargo, Tauri-rel
 nix develop
 ```
 
+### Linux GDK / GTK environment constraints
+
+On Linux, `chilla` depends on the GTK/WebKitGTK runtime prepared by `flake.nix`. In practice, that means:
+
+- Prefer running the app from `nix develop`, `task dev`, or `nix run .` so the wrapped GTK/GIO/GStreamer environment is applied.
+- Do not mix host GTK-related overrides into the dev shell. In particular, `GTK_PATH`, `GI_TYPELIB_PATH`, `GTK_IM_MODULE`, `QT_IM_MODULE`, and `XMODIFIERS` are intentionally unset to avoid loading incompatible host modules.
+- The Linux WebKitGTK renderer is currently run with `WEBKIT_DISABLE_DMABUF_RENDERER=1` because DMA-BUF rendering is not treated as stable for this app's environment.
+- If Linux media playback behaves differently from macOS, assume the Linux path is constrained by the WebKitGTK + GStreamer stack rather than the frontend alone.
+
+If you launch Tauri commands outside the Nix shell, you are responsible for providing a compatible GTK/WebKitGTK/GStreamer runtime yourself.
+
 ### Common commands
 
 ```bash

e2e/file-browser-keyboard.pw.ts

@@ -0,0 +1,69 @@
+import { expect, test } from "@playwright/test";
+
+const harnessPath = "/?harness=file-browser";
+
+test.describe("file browser keyboard navigation", () => {
+  test("moves focus and selection with j/k and confirms with l", async ({ page }) => {
+    await page.goto(harnessPath);
+
+    await page.waitForSelector('[data-testid="selected-path"]');
+    await expect(page.getByTestId("selected-path")).toHaveText(
+      "/workspace/bravo.md",
+    );
+    await expect(page.getByTestId("selected-index")).toHaveText("2");
+    await expect(page.locator(".file-browser__button:focus")).toHaveAttribute(
+      "data-path",
+      "/workspace/bravo.md",
+    );
+
+    await page.keyboard.press("j");
+    await expect(page.getByTestId("selected-path")).toHaveText(
+      "/workspace/delta.md",
+    );
+    await expect(page.locator(".file-browser__button:focus")).toHaveAttribute(
+      "data-path",
+      "/workspace/delta.md",
+    );
+
+    await page.keyboard.press("j");
+    await expect(page.getByTestId("selected-path")).toHaveText(
+      "/workspace/echo.txt",
+    );
+    await expect(page.locator(".file-browser__button:focus")).toHaveAttribute(
+      "data-path",
+      "/workspace/echo.txt",
+    );
+
+    await page.keyboard.press("k");
+    await expect(page.getByTestId("selected-path")).toHaveText(
+      "/workspace/delta.md",
+    );
+    await expect(page.locator(".file-browser__button:focus")).toHaveAttribute(
+      "data-path",
+      "/workspace/delta.md",
+    );
+
+    await page.keyboard.press("l");
+    await expect(page.getByTestId("confirmed-path")).toHaveText(
+      "/workspace/delta.md",
+    );
+  });
+
+  test("h triggers parent navigation while preserving list keyboard handling", async ({
+    page,
+  }) => {
+    await page.goto(harnessPath);
+    await expect(page.locator(".file-browser__button:focus")).toHaveAttribute(
+      "data-path",
+      "/workspace/bravo.md",
+    );
+
+    await page.keyboard.press("h");
+    await expect(page.getByTestId("parent-count")).toHaveText("1");
+
+    await page.keyboard.press("j");
+    await expect(page.getByTestId("selected-path")).toHaveText(
+      "/workspace/delta.md",
+    );
+  });
+});

flake.nix

@@ -200,11 +200,23 @@
             postFixup = lib.optionalString pkgs.stdenv.isLinux ''
               wrapProgram $out/bin/chilla \
                 --prefix LD_LIBRARY_PATH : "${linuxRuntimeLibraryPath}" \
+                --set GIO_EXTRA_MODULES "${linuxGioModulePath}" \
+                --set XDG_DATA_DIRS "${linuxXdgDataDirs}" \
+                --set WEBKIT_DISABLE_DMABUF_RENDERER 1 \
                 --set GST_PLUGIN_SCANNER "${linuxGStreamerPluginScanner}" \
                 --set GST_PLUGIN_SYSTEM_PATH "${linuxGStreamerPluginPath}" \
                 --prefix GST_PLUGIN_SYSTEM_PATH_1_0 : "${linuxGStreamerPluginPath}" \
                 --set GST_PLUGIN_PATH "${linuxGStreamerPluginPath}" \
-                --set GST_PLUGIN_PATH_1_0 "${linuxGStreamerPluginPath}"
+                --set GST_PLUGIN_PATH_1_0 "${linuxGStreamerPluginPath}" \
+                --unset GTK_PATH \
+                --unset GI_TYPELIB_PATH \
+                --unset GTK_IM_MODULE \
+                --unset GTK_IM_MODULE_FILE \
+                --unset QT_IM_MODULE \
+                --unset XMODIFIERS \
+                --unset GIO_MODULE_DIR \
+                --unset GTK_EXE_PREFIX \
+                --unset GTK_DATA_PREFIX
             '';
           };
 

impl-plans/active/file-viewer-mode.md

@@ -218,6 +218,10 @@ export interface StartupContext {
 **Notes**: The current app is centered on a single Markdown startup path. The feature will be implemented by adding startup context plus separate directory-listing/file-preview commands, while preserving the existing Markdown editor flow for Markdown mode. Image and video previews are part of the file-view contract.
 
 ### Session: 2026-03-21 JST
+**Tasks Completed**: Refactored directory listing contract to keep selection frontend-owned
+**Tasks In Progress**: TASK-002 Rust viewer service, TASK-003 frontend file view mode
+**Blockers**: Runtime keyboard behavior still needs manual validation in the app
+**Notes**: Removed `selected_path` / `selected_index` from the `list_directory` Tauri contract so the backend acts as a stateless page query service over `path`, `offset`, `limit`, `query`, and `sort`. Frontend selection is now owned locally in `WorkspaceShell`, including page-boundary keyboard navigation. Verified with `bun run typecheck`, `bun test`, `CARGO_TERM_QUIET=true cargo check -p chilla`, and `CARGO_TERM_QUIET=true cargo test -p chilla`.
 **Tasks Completed**: Extended the directory-entry contract with file size and modified-time metadata; added frontend file-tree sort modes and keyboard shortcuts for name, mtime, and size.
 **Tasks In Progress**: TASK-002 Rust viewer service, TASK-003 frontend file view mode, TASK-004 verification
 **Blockers**: None
@@ -228,3 +232,15 @@ export interface StartupContext {
 **Tasks In Progress**: TASK-003 frontend file view mode, TASK-004 verification
 **Blockers**: None
 **Notes**: The play overlay remains keyboard reachable, and the autoplay request id is now consumed once per preview load so repeated reactive updates do not retrigger stale playback requests.
+
+### Session: 2026-03-21 JST
+**Tasks Completed**: Tuned large-directory file-tree rendering by virtualizing the visible rows, moving scrolling into a dedicated viewport, and removing per-row truncation measurement observers that scaled with entry count.
+**Tasks In Progress**: TASK-003 frontend file view mode, TASK-004 verification
+**Blockers**: None
+**Notes**: The file tree now renders only the visible slice plus overscan, which keeps navigation responsive for large directories while preserving existing keyboard and focus behavior.
+
+### Session: 2026-03-21 JST
+**Tasks Completed**: Moved file-tree sort and filter evaluation to Rust, changed the directory-list contract to return a paged window with total counts and selection metadata, and updated the frontend file browser to request new windows as scroll/keyboard navigation moves across large directories.
+**Tasks In Progress**: TASK-003 frontend file view mode, TASK-004 verification
+**Blockers**: None
+**Notes**: Large directories such as `/nix/store` no longer require sending the entire entry list over Tauri in one response. The frontend now treats the Rust response as a movable window over the full sorted directory.

package.json

@@ -18,8 +18,9 @@
     "solid-js": "^1.9.3"
   },
   "devDependencies": {
-    "@types/bun": "^1.3.3",
+    "@playwright/test": "^1.58.2",
     "@tauri-apps/cli": "^2",
+    "@types/bun": "^1.3.3",
     "typescript": "~5.6.2",
     "vite": "^6.0.3",
     "vite-plugin-solid": "^2.11.0"

playwright.config.ts

@@ -0,0 +1,40 @@
+import { execSync } from "node:child_process";
+import { defineConfig } from "@playwright/test";
+
+function resolveChromiumExecutablePath(): string | undefined {
+  if (process.env.PLAYWRIGHT_CHROMIUM_EXECUTABLE) {
+    return process.env.PLAYWRIGHT_CHROMIUM_EXECUTABLE;
+  }
+
+  try {
+    const value = execSync("which chromium", {
+      stdio: ["ignore", "pipe", "ignore"],
+    })
+      .toString()
+      .trim();
+    return value === "" ? undefined : value;
+  } catch {
+    return undefined;
+  }
+}
+
+const chromiumExecutablePath = resolveChromiumExecutablePath();
+
+export default defineConfig({
+  testDir: "./e2e",
+  testMatch: "**/*.pw.ts",
+  timeout: 30_000,
+  use: {
+    baseURL: "http://localhost:1420",
+    headless: true,
+    launchOptions: chromiumExecutablePath
+      ? { executablePath: chromiumExecutablePath }
+      : undefined,
+  },
+  webServer: {
+    command: "bun run dev -- --host localhost",
+    url: "http://localhost:1420",
+    reuseExistingServer: true,
+    timeout: 120_000,
+  },
+});

src-tauri/Cargo.toml

@@ -22,7 +22,7 @@ syntect = { version = "5.3", default-features = false, features = [
   "html",
   "dump-load",
 ] }
-tauri = { version = "2", features = ["protocol-asset"] }
+tauri = { version = "2", features = ["custom-protocol", "protocol-asset"] }
 tauri-plugin-opener = "2.5.3"
 thiserror = "2"
 tree_magic_mini = "3.2.2"

src-tauri/src/commands/document.rs

@@ -7,7 +7,7 @@ use crate::{
     document::types::{DocumentSnapshot, HeadingNode},
     markdown::render_markdown,
     syntax_highlight::SyntaxUiTheme,
-    viewer::types::{DirectorySnapshot, FilePreview, StartupContext},
+    viewer::types::{DirectorySnapshot, DirectorySort, FilePreview, StartupContext},
 };
 
 fn format_command_error(error: impl std::fmt::Display) -> String {
@@ -48,12 +48,21 @@ pub fn get_startup_context(state: State<'_, AppState>) -> Result<StartupContext,
 #[tauri::command]
 pub fn list_directory(
     path: String,
-    selected_path: Option<String>,
+    offset: Option<usize>,
+    limit: Option<usize>,
+    query: Option<String>,
+    sort: Option<DirectorySort>,
     state: State<'_, AppState>,
 ) -> Result<DirectorySnapshot, String> {
     state
         .viewer_service()
-        .list_directory(Path::new(&path), selected_path.as_deref().map(Path::new))
+        .list_directory(
+            Path::new(&path),
+            offset,
+            limit,
+            query.as_deref(),
+            sort,
+        )
         .map_err(format_command_error)
 }