feat: show dynamic build number in status bar (bNNN format) (#163)

* feat: show dynamic build number in status bar (bNNN format)

Replace hardcoded v0.4.2 with a dynamic build number derived from
git rev-list --count HEAD at compile time. The count is embedded via
build.rs and exposed through a get_build_number Tauri command.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* design: add build-number-status-bar wireframes (status bar with dynamic b-number)

* fix: use runtime env var for BUILD_NUMBER (compile-time env! not available in CI)

* style: rustfmt format get_build_number

---------

Co-authored-by: Test <test@test.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

design/build-number-status-bar.pen

@@ -0,0 +1,96 @@
+{
+  "children": [
+    {
+      "type": "frame",
+      "id": "build_number_status_bar",
+      "name": "Build Number — Status Bar",
+      "x": 0,
+      "y": 0,
+      "width": 1200,
+      "height": 36,
+      "fill": "$--background",
+      "layout": "horizontal",
+      "gap": 12,
+      "padding": [
+        0,
+        16
+      ],
+      "theme": {
+        "Mode": "Light"
+      },
+      "children": [
+        {
+          "type": "text",
+          "id": "status_vault",
+          "content": "vault-name",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 12
+        },
+        {
+          "type": "text",
+          "id": "status_sep1",
+          "content": "|",
+          "fill": "$--border",
+          "fontFamily": "Inter",
+          "fontSize": 12
+        },
+        {
+          "type": "text",
+          "id": "status_build",
+          "content": "b223",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 12
+        },
+        {
+          "type": "text",
+          "id": "status_note",
+          "content": "← dynamic build number from package.json, replacing hardcoded v0.4.2",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 11,
+          "fontStyle": "italic"
+        }
+      ]
+    },
+    {
+      "type": "frame",
+      "id": "build_number_fallback",
+      "name": "Build Number — Fallback (no build info)",
+      "x": 0,
+      "y": 60,
+      "width": 400,
+      "height": 36,
+      "fill": "$--background",
+      "layout": "horizontal",
+      "gap": 12,
+      "padding": [
+        0,
+        16
+      ],
+      "theme": {
+        "Mode": "Light"
+      },
+      "children": [
+        {
+          "type": "text",
+          "id": "fallback_build",
+          "content": "b?",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 12
+        },
+        {
+          "type": "text",
+          "id": "fallback_note",
+          "content": "← shows b? when build number unavailable",
+          "fill": "$--muted-foreground",
+          "fontFamily": "Inter",
+          "fontSize": 11,
+          "fontStyle": "italic"
+        }
+      ]
+    }
+  ]
+}

src-tauri/build.rs

@@ -1,3 +1,14 @@
 fn main() {
+    let count = std::process::Command::new("git")
+        .args(["rev-list", "--count", "HEAD"])
+        .output()
+        .ok()
+        .filter(|o| o.status.success())
+        .and_then(|o| String::from_utf8(o.stdout).ok())
+        .map(|s| s.trim().to_string())
+        .unwrap_or_else(|| "DEV".to_string());
+
+    println!("cargo:rustc-env=BUILD_NUMBER={}", count);
+
     tauri_build::build()
 }

src-tauri/src/lib.rs

@@ -112,6 +112,14 @@ fn git_commit(vault_path: String, message: String) -> Result<String, String> {
     git::git_commit(&vault_path, &message)
 }
 
+#[tauri::command]
+fn get_build_number() -> String {
+    {
+        let n = std::env::var("BUILD_NUMBER").unwrap_or_else(|_| "0".to_string());
+        format!("b{}", n)
+    }
+}
+
 #[tauri::command]
 fn get_last_commit_info(vault_path: String) -> Result<Option<LastCommitInfo>, String> {
     let vault_path = expand_tilde(&vault_path);
@@ -435,6 +443,16 @@ mod tests {
         let result = expand_tilde("/home/~user/path");
         assert_eq!(result, "/home/~user/path");
     }
+
+    #[test]
+    fn get_build_number_returns_prefixed_value() {
+        let result = get_build_number();
+        assert!(
+            result.starts_with('b'),
+            "expected 'b' prefix, got: {}",
+            result
+        );
+    }
 }
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
@@ -498,6 +516,7 @@ pub fn run() {
             get_file_diff,
             get_file_diff_at_commit,
             git_commit,
+            get_build_number,
             get_last_commit_info,
             git_pull,
             git_push,

src/App.tsx

@@ -29,6 +29,7 @@ import { useUpdater } from './hooks/useUpdater'
 import { useNavigationHistory } from './hooks/useNavigationHistory'
 import { useAutoSync } from './hooks/useAutoSync'
 import { useZoom } from './hooks/useZoom'
+import { useBuildNumber } from './hooks/useBuildNumber'
 import { useOnboarding } from './hooks/useOnboarding'
 import { useThemeManager } from './hooks/useThemeManager'
 import { UpdateBanner } from './components/UpdateBanner'
@@ -260,6 +261,7 @@ function App() {
 
   const { setViewMode, sidebarVisible, noteListVisible } = useViewMode()
   const zoom = useZoom()
+  const buildNumber = useBuildNumber()
 
   const commands = useAppCommands({
     activeTabPath: notes.activeTabPath, activeTabPathRef: notes.activeTabPathRef,
@@ -384,7 +386,7 @@ function App() {
         </div>
       </div>
       <UpdateBanner status={updateStatus} actions={updateActions} />
-      <StatusBar noteCount={vault.entries.length} modifiedCount={vault.modifiedFiles.length} vaultPath={vaultSwitcher.vaultPath} vaults={vaultSwitcher.allVaults} onSwitchVault={vaultSwitcher.switchVault} onOpenSettings={dialogs.openSettings} onOpenLocalFolder={vaultSwitcher.handleOpenLocalFolder} onConnectGitHub={dialogs.openGitHubVault} onClickPending={() => setSelection({ kind: 'filter', filter: 'changes' })} hasGitHub={!!settings.github_token} syncStatus={autoSync.syncStatus} lastSyncTime={autoSync.lastSyncTime} conflictCount={autoSync.conflictFiles.length} lastCommitInfo={autoSync.lastCommitInfo} onTriggerSync={autoSync.triggerSync} zoomLevel={zoom.zoomLevel} onZoomReset={zoom.zoomReset} />
+      <StatusBar noteCount={vault.entries.length} modifiedCount={vault.modifiedFiles.length} vaultPath={vaultSwitcher.vaultPath} vaults={vaultSwitcher.allVaults} onSwitchVault={vaultSwitcher.switchVault} onOpenSettings={dialogs.openSettings} onOpenLocalFolder={vaultSwitcher.handleOpenLocalFolder} onConnectGitHub={dialogs.openGitHubVault} onClickPending={() => setSelection({ kind: 'filter', filter: 'changes' })} hasGitHub={!!settings.github_token} syncStatus={autoSync.syncStatus} lastSyncTime={autoSync.lastSyncTime} conflictCount={autoSync.conflictFiles.length} lastCommitInfo={autoSync.lastCommitInfo} onTriggerSync={autoSync.triggerSync} zoomLevel={zoom.zoomLevel} onZoomReset={zoom.zoomReset} buildNumber={buildNumber} />
       <Toast message={toastMessage} onDismiss={() => setToastMessage(null)} />
       <QuickOpenPalette open={dialogs.showQuickOpen} entries={vault.entries} onSelect={notes.handleSelectNote} onClose={dialogs.closeQuickOpen} />
       <CommandPalette open={dialogs.showCommandPalette} commands={commands} onClose={dialogs.closeCommandPalette} />

src/components/StatusBar.test.tsx

@@ -25,9 +25,14 @@ describe('StatusBar', () => {
     expect(screen.getByText('9,200 notes')).toBeInTheDocument()
   })
 
-  it('displays version info', () => {
+  it('displays build number when provided', () => {
+    render(<StatusBar noteCount={100} vaultPath="/Users/luca/Laputa" vaults={vaults} onSwitchVault={vi.fn()} buildNumber="b223" />)
+    expect(screen.getByText('b223')).toBeInTheDocument()
+  })
+
+  it('displays fallback build number when not provided', () => {
     render(<StatusBar noteCount={100} vaultPath="/Users/luca/Laputa" vaults={vaults} onSwitchVault={vi.fn()} />)
-    expect(screen.getByText('v0.4.2')).toBeInTheDocument()
+    expect(screen.getByText('b?')).toBeInTheDocument()
   })
 
   it('does not display branch name', () => {

src/components/StatusBar.tsx

@@ -26,6 +26,7 @@ interface StatusBarProps {
   onTriggerSync?: () => void
   zoomLevel?: number
   onZoomReset?: () => void
+  buildNumber?: string
 }
 
 function VaultMenuItem({ vault, isActive, onSelect }: { vault: VaultOption; isActive: boolean; onSelect: () => void }) {
@@ -155,7 +156,7 @@ function CommitBadge({ info }: { info: LastCommitInfo }) {
   )
 }
 
-export function StatusBar({ noteCount, modifiedCount = 0, vaultPath, vaults, onSwitchVault, onOpenSettings, onOpenLocalFolder, onConnectGitHub, onClickPending, hasGitHub, syncStatus = 'idle', lastSyncTime = null, conflictCount = 0, lastCommitInfo, onTriggerSync, zoomLevel = 100, onZoomReset }: StatusBarProps) {
+export function StatusBar({ noteCount, modifiedCount = 0, vaultPath, vaults, onSwitchVault, onOpenSettings, onOpenLocalFolder, onConnectGitHub, onClickPending, hasGitHub, syncStatus = 'idle', lastSyncTime = null, conflictCount = 0, lastCommitInfo, onTriggerSync, zoomLevel = 100, onZoomReset, buildNumber }: StatusBarProps) {
   // Force re-render every 30s to keep relative time label fresh
   const [, setTick] = useState(0)
   useEffect(() => {
@@ -171,7 +172,7 @@ export function StatusBar({ noteCount, modifiedCount = 0, vaultPath, vaults, onS
       <div style={{ display: 'flex', alignItems: 'center', gap: 12 }}>
         <VaultMenu vaults={vaults} vaultPath={vaultPath} onSwitchVault={onSwitchVault} onOpenLocalFolder={onOpenLocalFolder} onConnectGitHub={onConnectGitHub} hasGitHub={hasGitHub} />
         <span style={SEP_STYLE}>|</span>
-        <span style={ICON_STYLE}><Package size={13} />v0.4.2</span>
+        <span style={ICON_STYLE} data-testid="status-build-number"><Package size={13} />{buildNumber ?? 'b?'}</span>
         <span style={SEP_STYLE}>|</span>
         <span
           role="button"

src/hooks/useBuildNumber.test.ts

@@ -0,0 +1,25 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { renderHook, waitFor } from '@testing-library/react'
+import { useBuildNumber } from './useBuildNumber'
+
+vi.mock('@tauri-apps/api/core', () => ({ invoke: vi.fn() }))
+vi.mock('../mock-tauri', () => ({
+  isTauri: () => false,
+  mockInvoke: vi.fn().mockResolvedValue('b223'),
+}))
+
+beforeEach(() => { vi.clearAllMocks() })
+
+describe('useBuildNumber', () => {
+  it('returns build number from mock invoke', async () => {
+    const { result } = renderHook(() => useBuildNumber())
+    await waitFor(() => expect(result.current).toBe('b223'))
+  })
+
+  it('returns fallback on error', async () => {
+    const { mockInvoke } = await import('../mock-tauri')
+    vi.mocked(mockInvoke).mockRejectedValueOnce(new Error('fail'))
+    const { result } = renderHook(() => useBuildNumber())
+    await waitFor(() => expect(result.current).toBe('b?'))
+  })
+})

src/hooks/useBuildNumber.ts

@@ -0,0 +1,19 @@
+import { useState, useEffect } from 'react'
+import { invoke } from '@tauri-apps/api/core'
+import { isTauri, mockInvoke } from '../mock-tauri'
+
+function tauriCall<T>(cmd: string): Promise<T> {
+  return isTauri() ? invoke<T>(cmd) : mockInvoke<T>(cmd)
+}
+
+export function useBuildNumber(): string | undefined {
+  const [buildNumber, setBuildNumber] = useState<string>()
+
+  useEffect(() => {
+    tauriCall<string>('get_build_number').then(setBuildNumber).catch(() => {
+      setBuildNumber('b?')
+    })
+  }, [])
+
+  return buildNumber
+}

src/mock-tauri/mock-handlers.ts

@@ -162,6 +162,7 @@ export const mockHandlers: Record<string, (args: any) => any> = {
     mockSavedSinceCommit.clear()
     return `[main abc1234] ${args.message}\n ${count} files changed`
   },
+  get_build_number: () => 'bDEV',
   get_last_commit_info: (): LastCommitInfo => ({ shortHash: 'a1b2c3d', commitUrl: 'https://github.com/lucaong/laputa-vault/commit/a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0' }),
   git_pull: (): GitPullResult => ({ status: 'up_to_date', message: 'Already up to date', updatedFiles: [], conflictFiles: [] }),
   git_push: () => 'Everything up-to-date',