Add git worktree support

app/src/lib/app-state.ts

@@ -196,6 +196,9 @@ export interface IAppState {
   /** The width of the resizable branch drop down button in the toolbar. */
   readonly branchDropdownWidth: IConstrainedValue
 
+  /** The width of the resizable worktree drop down button in the toolbar. */
+  readonly worktreeDropdownWidth: IConstrainedValue
+
   /** The width of the resizable push/pull button in the toolbar. */
   readonly pushPullButtonWidth: IConstrainedValue
 
@@ -310,6 +313,9 @@ export interface IAppState {
   /** Whether or not recent repositories should be shown in the repo list */
   readonly showRecentRepositories: boolean
 
+  /** Whether or not the worktrees dropdown should be shown in the toolbar */
+  readonly showWorktrees: boolean
+
   /**
    * A map keyed on a user account (GitHub.com or GitHub Enterprise)
    * containing an object with repositories that the authenticated
@@ -411,6 +417,7 @@ export enum FoldoutType {
   AppMenu,
   AddMenu,
   PushPull,
+  Worktree,
 }
 
 export type AppMenuFoldout = {
@@ -434,6 +441,7 @@ export type Foldout =
   | BranchFoldout
   | AppMenuFoldout
   | { type: FoldoutType.PushPull }
+  | { type: FoldoutType.Worktree }
 
 export enum RepositorySectionTab {
   Changes,

app/src/lib/git/index.ts

@@ -33,3 +33,4 @@ export * from './gitignore'
 export * from './rebase'
 export * from './format-patch'
 export * from './tag'
+export * from './worktree'

app/src/lib/git/worktree.ts

@@ -0,0 +1,155 @@
+import * as Path from 'path'
+import * as Fs from 'fs'
+import type { Repository } from '../../models/repository'
+import type { WorktreeEntry, WorktreeType } from '../../models/worktree'
+import { git } from './core'
+
+export function parseWorktreePorcelainOutput(
+  stdout: string
+): ReadonlyArray<WorktreeEntry> {
+  if (stdout.trim().length === 0) {
+    return []
+  }
+
+  const blocks = stdout.trim().split('\n\n')
+  const entries: WorktreeEntry[] = []
+
+  for (let i = 0; i < blocks.length; i++) {
+    const lines = blocks[i].split('\n')
+    let path = ''
+    let head = ''
+    let branch: string | null = null
+    let isDetached = false
+    let isLocked = false
+    let isPrunable = false
+
+    for (const line of lines) {
+      if (line.startsWith('worktree ')) {
+        path = line.substring('worktree '.length)
+      } else if (line.startsWith('HEAD ')) {
+        head = line.substring('HEAD '.length)
+      } else if (line.startsWith('branch ')) {
+        branch = line.substring('branch '.length)
+      } else if (line === 'detached') {
+        isDetached = true
+      } else if (line === 'locked' || line.startsWith('locked ')) {
+        isLocked = true
+      } else if (line === 'prunable' || line.startsWith('prunable ')) {
+        isPrunable = true
+      }
+    }
+
+    const type: WorktreeType = i === 0 ? 'main' : 'linked'
+    entries.push({ path, head, branch, isDetached, type, isLocked, isPrunable })
+  }
+
+  return entries
+}
+
+export async function listWorktrees(
+  repository: Repository
+): Promise<ReadonlyArray<WorktreeEntry>> {
+  const result = await git(
+    ['worktree', 'list', '--porcelain'],
+    repository.path,
+    'listWorktrees'
+  )
+
+  return parseWorktreePorcelainOutput(result.stdout)
+}
+
+export async function addWorktree(
+  repository: Repository,
+  path: string,
+  options: {
+    readonly branch?: string
+    readonly createBranch?: string
+    readonly detach?: boolean
+    readonly commitish?: string
+  } = {}
+): Promise<void> {
+  const args = ['worktree', 'add']
+
+  if (options.detach) {
+    args.push('--detach')
+  }
+
+  if (options.createBranch) {
+    args.push('-b', options.createBranch)
+  }
+
+  args.push(path)
+
+  if (options.branch) {
+    args.push(options.branch)
+  } else if (options.commitish) {
+    args.push(options.commitish)
+  }
+
+  await git(args, repository.path, 'addWorktree')
+}
+
+export async function removeWorktree(
+  repository: Repository,
+  path: string,
+  force: boolean = false
+): Promise<void> {
+  const args = ['worktree', 'remove']
+  if (force) {
+    args.push('--force')
+  }
+  args.push(path)
+
+  await git(args, repository.path, 'removeWorktree')
+}
+
+export async function moveWorktree(
+  repository: Repository,
+  oldPath: string,
+  newPath: string
+): Promise<void> {
+  await git(
+    ['worktree', 'move', oldPath, newPath],
+    repository.path,
+    'moveWorktree'
+  )
+}
+
+export async function isLinkedWorktree(
+  repository: Repository
+): Promise<boolean> {
+  const worktrees = await listWorktrees(repository)
+  const repoPath = repository.path
+
+  return worktrees.some(
+    wt =>
+      wt.type === 'linked' && normalizePath(wt.path) === normalizePath(repoPath)
+  )
+}
+
+export async function getMainWorktreePath(
+  repository: Repository
+): Promise<string | null> {
+  const worktrees = await listWorktrees(repository)
+  const main = worktrees.find(wt => wt.type === 'main')
+  return main?.path ?? null
+}
+
+/**
+ * Synchronously checks if a repository path is a linked worktree by examining
+ * whether `.git` is a file (linked worktree) or directory (main worktree).
+ */
+export function isLinkedWorktreeSync(repositoryPath: string): boolean {
+  try {
+    const dotGit = Path.join(repositoryPath, '.git')
+    // eslint-disable-next-line no-sync
+    const stats = Fs.statSync(dotGit)
+    return stats.isFile()
+  } catch {
+    return false
+  }
+}
+
+function normalizePath(p: string): string {
+  return p.replace(/\/+$/, '')
+}

app/src/lib/stores/app-store.ts

@@ -390,6 +390,9 @@ const pullRequestFileListConfigKey: string = 'pull-request-files-width'
 const defaultBranchDropdownWidth: number = 230
 const branchDropdownWidthConfigKey: string = 'branch-dropdown-width'
 
+const defaultWorktreeDropdownWidth: number = 230
+const worktreeDropdownWidthConfigKey: string = 'worktree-dropdown-width'
+
 const defaultPushPullButtonWidth: number = 230
 const pushPullButtonWidthConfigKey: string = 'push-pull-button-width'
 
@@ -442,6 +445,7 @@ const tabSizeKey: string = 'tab-size'
 const shellKey = 'shell'
 
 const showRecentRepositoriesKey = 'show-recent-repositories'
+const showWorktreesKey = 'show-worktrees'
 const repositoryIndicatorsEnabledKey = 'enable-repository-indicators'
 
 // background fetching should occur hourly when Desktop is active, but this
@@ -539,6 +543,7 @@ export class AppStore extends TypedBaseStore<IAppState> {
   private stashedFilesWidth = constrain(defaultStashedFilesWidth)
   private pullRequestFileListWidth = constrain(defaultPullRequestFileListWidth)
   private branchDropdownWidth = constrain(defaultBranchDropdownWidth)
+  private worktreeDropdownWidth = constrain(defaultWorktreeDropdownWidth)
   private pushPullButtonWidth = constrain(defaultPushPullButtonWidth)
 
   private windowState: WindowState | null = null
@@ -603,6 +608,7 @@ export class AppStore extends TypedBaseStore<IAppState> {
   private selectedTabSize = tabSizeDefault
   private titleBarStyle: TitleBarStyle = 'native'
   private showRecentRepositories: boolean = true
+  private showWorktrees: boolean = false
   private hideWindowOnQuit: boolean = false
 
   private useWindowsOpenSSH: boolean = false
@@ -711,6 +717,7 @@ export class AppStore extends TypedBaseStore<IAppState> {
       getBoolean(repositoryIndicatorsEnabledKey) ?? true
 
     this.showRecentRepositories = getBoolean(showRecentRepositoriesKey) ?? true
+    this.showWorktrees = getBoolean(showWorktreesKey) ?? false
 
     this.repositoryIndicatorUpdater = new RepositoryIndicatorUpdater(
       this.getRepositoriesForIndicatorRefresh,
@@ -1104,6 +1111,7 @@ export class AppStore extends TypedBaseStore<IAppState> {
       emoji: this.emoji,
       sidebarWidth: this.sidebarWidth,
       branchDropdownWidth: this.branchDropdownWidth,
+      worktreeDropdownWidth: this.worktreeDropdownWidth,
       pushPullButtonWidth: this.pushPullButtonWidth,
       commitSummaryWidth: this.commitSummaryWidth,
       stashedFilesWidth: this.stashedFilesWidth,
@@ -1146,6 +1154,7 @@ export class AppStore extends TypedBaseStore<IAppState> {
       selectedTabSize: this.selectedTabSize,
       titleBarStyle: this.titleBarStyle,
       showRecentRepositories: this.showRecentRepositories,
+      showWorktrees: this.showWorktrees,
       apiRepositories: this.apiRepositoriesStore.getState(),
       useWindowsOpenSSH: this.useWindowsOpenSSH,
       showCommitLengthWarning: this.showCommitLengthWarning,
@@ -2373,6 +2382,9 @@ export class AppStore extends TypedBaseStore<IAppState> {
     this.branchDropdownWidth = constrain(
       getNumber(branchDropdownWidthConfigKey, defaultBranchDropdownWidth)
     )
+    this.worktreeDropdownWidth = constrain(
+      getNumber(worktreeDropdownWidthConfigKey, defaultWorktreeDropdownWidth)
+    )
     this.pushPullButtonWidth = constrain(
       getNumber(pushPullButtonWidthConfigKey, defaultPushPullButtonWidth)
     )
@@ -2564,12 +2576,13 @@ export class AppStore extends TypedBaseStore<IAppState> {
    * dimensions change.
    */
   private updateResizableConstraints() {
-    // The combined width of the branch dropdown and the push/pull/fetch button
+    // The combined width of the toolbar buttons (worktree, branch, push/pull).
     // Since the repository list toolbar button width is tied to the width of
-    // the sidebar we can't let it push the branch, and push/pull/fetch button
-    // off screen.
+    // the sidebar we can't let it push these buttons off screen.
     const toolbarButtonsMinWidth =
-      defaultPushPullButtonWidth + defaultBranchDropdownWidth
+      defaultPushPullButtonWidth +
+      defaultBranchDropdownWidth +
+      defaultWorktreeDropdownWidth
 
     // Start with all the available width
     let available = window.innerWidth
@@ -2606,27 +2619,40 @@ export class AppStore extends TypedBaseStore<IAppState> {
     this.commitSummaryWidth = constrain(this.commitSummaryWidth, 100, filesMax)
     this.stashedFilesWidth = constrain(this.stashedFilesWidth, 100, filesMax)
 
-    // Update the maximum width available for the branch dropdown resizable.
-    // The branch dropdown can only be as wide as the available space after
-    // taking the sidebar and pull/push/fetch button widths. If the room
-    // available is less than the default width, we will split the difference
-    // between the branch dropdown and the push/pull/fetch button so they stay
-    // visible on the most zoomed view.
-    const branchDropdownMax = available - defaultPushPullButtonWidth
+    // Allocate branch first (highest priority), then worktree, then
+    // push-pull. Each subsequent allocation uses the clamped value of the
+    // previous to prevent the total from exceeding the available space.
+    const branchDropdownMax =
+      available - defaultWorktreeDropdownWidth - defaultPushPullButtonWidth
     const minimumBranchDropdownWidth =
-      defaultBranchDropdownWidth > available / 2
-        ? available / 2 - 10 // 10 is to give a little bit of space to see the fetch dropdown button
+      defaultBranchDropdownWidth > available / 3
+        ? available / 3 - 10
         : defaultBranchDropdownWidth
     this.branchDropdownWidth = constrain(
       this.branchDropdownWidth,
       minimumBranchDropdownWidth,
       branchDropdownMax
     )
 
-    const pushPullButtonMaxWidth = available - this.branchDropdownWidth.value
+    const worktreeDropdownMax =
+      available - clamp(this.branchDropdownWidth) - defaultPushPullButtonWidth
+    const minimumWorktreeDropdownWidth =
+      defaultWorktreeDropdownWidth > available / 3
+        ? available / 3 - 10
+        : defaultWorktreeDropdownWidth
+    this.worktreeDropdownWidth = constrain(
+      this.worktreeDropdownWidth,
+      minimumWorktreeDropdownWidth,
+      worktreeDropdownMax
+    )
+
+    const pushPullButtonMaxWidth =
+      available -
+      clamp(this.branchDropdownWidth) -
+      clamp(this.worktreeDropdownWidth)
     const minimumPushPullToolBarWidth =
-      defaultPushPullButtonWidth > available / 2
-        ? available / 2 + 30 // 30 to clip the fetch dropdown button in favor of seeing more of the words on the toolbar buttons
+      defaultPushPullButtonWidth > available / 3
+        ? available / 3
         : defaultPushPullButtonWidth
     this.pushPullButtonWidth = constrain(
       this.pushPullButtonWidth,
@@ -4022,6 +4048,15 @@ export class AppStore extends TypedBaseStore<IAppState> {
     this.emitUpdate()
   }
 
+  public _setShowWorktrees(showWorktrees: boolean) {
+    if (this.showWorktrees === showWorktrees) {
+      return
+    }
+    setBoolean(showWorktreesKey, showWorktrees)
+    this.showWorktrees = showWorktrees
+    this.emitUpdate()
+  }
+
   public _setCommitSpellcheckEnabled(commitSpellcheckEnabled: boolean) {
     if (this.commitSpellcheckEnabled === commitSpellcheckEnabled) {
       return
@@ -5763,6 +5798,30 @@ export class AppStore extends TypedBaseStore<IAppState> {
     return Promise.resolve()
   }
 
+  public _setWorktreeDropdownWidth(width: number): Promise<void> {
+    this.worktreeDropdownWidth = {
+      ...this.worktreeDropdownWidth,
+      value: width,
+    }
+    setNumber(worktreeDropdownWidthConfigKey, width)
+    this.updateResizableConstraints()
+    this.emitUpdate()
+
+    return Promise.resolve()
+  }
+
+  public _resetWorktreeDropdownWidth(): Promise<void> {
+    this.worktreeDropdownWidth = {
+      ...this.worktreeDropdownWidth,
+      value: defaultWorktreeDropdownWidth,
+    }
+    localStorage.removeItem(worktreeDropdownWidthConfigKey)
+    this.updateResizableConstraints()
+    this.emitUpdate()
+
+    return Promise.resolve()
+  }
+
   public _setPushPullButtonWidth(width: number): Promise<void> {
     this.pushPullButtonWidth = { ...this.pushPullButtonWidth, value: width }
     setNumber(pushPullButtonWidthConfigKey, width)