Feature: Git sync, set-tracking, and push divergence handling (#796)

apps/server/src/routes/worktree/index.ts

@@ -67,6 +67,8 @@ import { createAbortOperationHandler } from './routes/abort-operation.js';
 import { createContinueOperationHandler } from './routes/continue-operation.js';
 import { createStageFilesHandler } from './routes/stage-files.js';
 import { createCheckChangesHandler } from './routes/check-changes.js';
+import { createSetTrackingHandler } from './routes/set-tracking.js';
+import { createSyncHandler } from './routes/sync.js';
 import type { SettingsService } from '../../services/settings-service.js';
 
 export function createWorktreeRoutes(
@@ -118,6 +120,18 @@ export function createWorktreeRoutes(
     requireValidWorktree,
     createPullHandler()
   );
+  router.post(
+    '/sync',
+    validatePathParams('worktreePath'),
+    requireValidWorktree,
+    createSyncHandler()
+  );
+  router.post(
+    '/set-tracking',
+    validatePathParams('worktreePath'),
+    requireValidWorktree,
+    createSetTrackingHandler()
+  );
   router.post(
     '/checkout-branch',
     validatePathParams('worktreePath'),

apps/server/src/routes/worktree/routes/push.ts

@@ -1,24 +1,24 @@
 /**
  * POST /push endpoint - Push a worktree branch to remote
  *
+ * Git business logic is delegated to push-service.ts.
+ *
  * Note: Git repository validation (isGitRepo, hasCommits) is handled by
  * the requireValidWorktree middleware in index.ts
  */
 
 import type { Request, Response } from 'express';
-import { exec } from 'child_process';
-import { promisify } from 'util';
 import { getErrorMessage, logError } from '../common.js';
-
-const execAsync = promisify(exec);
+import { performPush } from '../../../services/push-service.js';
 
 export function createPushHandler() {
   return async (req: Request, res: Response): Promise<void> => {
     try {
-      const { worktreePath, force, remote } = req.body as {
+      const { worktreePath, force, remote, autoResolve } = req.body as {
         worktreePath: string;
         force?: boolean;
         remote?: string;
+        autoResolve?: boolean;
       };
 
       if (!worktreePath) {
@@ -29,34 +29,28 @@ export function createPushHandler() {
         return;
       }
 
-      // Get branch name
-      const { stdout: branchOutput } = await execAsync('git rev-parse --abbrev-ref HEAD', {
-        cwd: worktreePath,
-      });
-      const branchName = branchOutput.trim();
+      const result = await performPush(worktreePath, { remote, force, autoResolve });
 
-      // Use specified remote or default to 'origin'
-      const targetRemote = remote || 'origin';
-
-      // Push the branch
-      const forceFlag = force ? '--force' : '';
-      try {
-        await execAsync(`git push -u ${targetRemote} ${branchName} ${forceFlag}`, {
-          cwd: worktreePath,
-        });
-      } catch {
-        // Try setting upstream
-        await execAsync(`git push --set-upstream ${targetRemote} ${branchName} ${forceFlag}`, {
-          cwd: worktreePath,
+      if (!result.success) {
+        const statusCode = isClientError(result.error ?? '') ? 400 : 500;
+        res.status(statusCode).json({
+          success: false,
+          error: result.error,
+          diverged: result.diverged,
+          hasConflicts: result.hasConflicts,
+          conflictFiles: result.conflictFiles,
         });
+        return;
       }
 
       res.json({
         success: true,
         result: {
-          branch: branchName,
-          pushed: true,
-          message: `Successfully pushed ${branchName} to ${targetRemote}`,
+          branch: result.branch,
+          pushed: result.pushed,
+          diverged: result.diverged,
+          autoResolved: result.autoResolved,
+          message: result.message,
         },
       });
     } catch (error) {
@@ -65,3 +59,15 @@ export function createPushHandler() {
     }
   };
 }
+
+/**
+ * Determine whether an error message represents a client error (400)
+ * vs a server error (500).
+ */
+function isClientError(errorMessage: string): boolean {
+  return (
+    errorMessage.includes('detached HEAD') ||
+    errorMessage.includes('rejected') ||
+    errorMessage.includes('diverged')
+  );
+}

apps/server/src/routes/worktree/routes/set-tracking.ts

@@ -0,0 +1,76 @@
+/**
+ * POST /set-tracking endpoint - Set the upstream tracking branch for a worktree
+ *
+ * Sets `git branch --set-upstream-to=<remote>/<branch>` for the current branch.
+ *
+ * Note: Git repository validation (isGitRepo, hasCommits) is handled by
+ * the requireValidWorktree middleware in index.ts
+ */
+
+import type { Request, Response } from 'express';
+import { execGitCommand } from '@automaker/git-utils';
+import { getErrorMessage, logError } from '../common.js';
+import { getCurrentBranch } from '../../../lib/git.js';
+
+export function createSetTrackingHandler() {
+  return async (req: Request, res: Response): Promise<void> => {
+    try {
+      const { worktreePath, remote, branch } = req.body as {
+        worktreePath: string;
+        remote: string;
+        branch?: string;
+      };
+
+      if (!worktreePath) {
+        res.status(400).json({ success: false, error: 'worktreePath required' });
+        return;
+      }
+
+      if (!remote) {
+        res.status(400).json({ success: false, error: 'remote required' });
+        return;
+      }
+
+      // Get current branch if not provided
+      let targetBranch = branch;
+      if (!targetBranch) {
+        try {
+          targetBranch = await getCurrentBranch(worktreePath);
+        } catch (err) {
+          res.status(400).json({
+            success: false,
+            error: `Failed to get current branch: ${getErrorMessage(err)}`,
+          });
+          return;
+        }
+
+        if (targetBranch === 'HEAD') {
+          res.status(400).json({
+            success: false,
+            error: 'Cannot set tracking in detached HEAD state.',
+          });
+          return;
+        }
+      }
+
+      // Set upstream tracking (pass local branch name as final arg to be explicit)
+      await execGitCommand(
+        ['branch', '--set-upstream-to', `${remote}/${targetBranch}`, targetBranch],
+        worktreePath
+      );
+
+      res.json({
+        success: true,
+        result: {
+          branch: targetBranch,
+          remote,
+          upstream: `${remote}/${targetBranch}`,
+          message: `Set tracking branch to ${remote}/${targetBranch}`,
+        },
+      });
+    } catch (error) {
+      logError(error, 'Set tracking branch failed');
+      res.status(500).json({ success: false, error: getErrorMessage(error) });
+    }
+  };
+}

apps/server/src/routes/worktree/routes/sync.ts

@@ -0,0 +1,66 @@
+/**
+ * POST /sync endpoint - Pull then push a worktree branch
+ *
+ * Performs a full sync operation: pull latest from remote, then push
+ * local commits. Handles divergence automatically.
+ *
+ * Git business logic is delegated to sync-service.ts.
+ *
+ * Note: Git repository validation (isGitRepo, hasCommits) is handled by
+ * the requireValidWorktree middleware in index.ts
+ */
+
+import type { Request, Response } from 'express';
+import { getErrorMessage, logError } from '../common.js';
+import { performSync } from '../../../services/sync-service.js';
+
+export function createSyncHandler() {
+  return async (req: Request, res: Response): Promise<void> => {
+    try {
+      const { worktreePath, remote } = req.body as {
+        worktreePath: string;
+        remote?: string;
+      };
+
+      if (!worktreePath) {
+        res.status(400).json({
+          success: false,
+          error: 'worktreePath required',
+        });
+        return;
+      }
+
+      const result = await performSync(worktreePath, { remote });
+
+      if (!result.success) {
+        const statusCode = result.hasConflicts ? 409 : 500;
+        res.status(statusCode).json({
+          success: false,
+          error: result.error,
+          hasConflicts: result.hasConflicts,
+          conflictFiles: result.conflictFiles,
+          conflictSource: result.conflictSource,
+          pulled: result.pulled,
+          pushed: result.pushed,
+        });
+        return;
+      }
+
+      res.json({
+        success: true,
+        result: {
+          branch: result.branch,
+          pulled: result.pulled,
+          pushed: result.pushed,
+          isFastForward: result.isFastForward,
+          isMerge: result.isMerge,
+          autoResolved: result.autoResolved,
+          message: result.message,
+        },
+      });
+    } catch (error) {
+      logError(error, 'Sync worktree failed');
+      res.status(500).json({ success: false, error: getErrorMessage(error) });
+    }
+  };
+}

apps/server/src/services/push-service.ts

@@ -0,0 +1,258 @@
+/**
+ * PushService - Push git operations without HTTP
+ *
+ * Encapsulates the full git push workflow including:
+ * - Branch name and detached HEAD detection
+ * - Safe array-based command execution (no shell interpolation)
+ * - Divergent branch detection and auto-resolution via pull-then-retry
+ * - Structured result reporting
+ *
+ * Mirrors the pull-service.ts pattern for consistency.
+ */
+
+import { createLogger, getErrorMessage } from '@automaker/utils';
+import { execGitCommand } from '@automaker/git-utils';
+import { getCurrentBranch } from '../lib/git.js';
+import { performPull } from './pull-service.js';
+
+const logger = createLogger('PushService');
+
+// ============================================================================
+// Types
+// ============================================================================
+
+export interface PushOptions {
+  /** Remote name to push to (defaults to 'origin') */
+  remote?: string;
+  /** Force push */
+  force?: boolean;
+  /** When true and push is rejected due to divergence, pull then retry push */
+  autoResolve?: boolean;
+}
+
+export interface PushResult {
+  success: boolean;
+  error?: string;
+  branch?: string;
+  pushed?: boolean;
+  /** Whether the push was initially rejected because the branches diverged */
+  diverged?: boolean;
+  /** Whether divergence was automatically resolved via pull-then-retry */
+  autoResolved?: boolean;
+  /** Whether the auto-resolve pull resulted in merge conflicts */
+  hasConflicts?: boolean;
+  /** Files with merge conflicts (only when hasConflicts is true) */
+  conflictFiles?: string[];
+  message?: string;
+}
+
+// ============================================================================
+// Helper Functions
+// ============================================================================
+
+/**
+ * Detect whether push error output indicates a diverged/non-fast-forward rejection.
+ */
+function isDivergenceError(errorOutput: string): boolean {
+  const lower = errorOutput.toLowerCase();
+  // Require specific divergence indicators rather than just 'rejected' alone,
+  // which could match pre-receive hook rejections or protected branch errors.
+  const hasNonFastForward = lower.includes('non-fast-forward');
+  const hasFetchFirst = lower.includes('fetch first');
+  const hasFailedToPush = lower.includes('failed to push some refs');
+  const hasRejected = lower.includes('rejected');
+  return hasNonFastForward || hasFetchFirst || (hasRejected && hasFailedToPush);
+}
+
+// ============================================================================
+// Main Service Function
+// ============================================================================
+
+/**
+ * Perform a git push on the given worktree.
+ *
+ * The workflow:
+ * 1. Get current branch name (detect detached HEAD)
+ * 2. Attempt `git push <remote> <branch>` with safe array args
+ * 3. If push fails with divergence and autoResolve is true:
+ *    a. Pull from the same remote (with stash support)
+ *    b. If pull succeeds without conflicts, retry push
+ * 4. If push fails with "no upstream" error, retry with --set-upstream
+ * 5. Return structured result
+ *
+ * @param worktreePath - Path to the git worktree
+ * @param options - Push options (remote, force, autoResolve)
+ * @returns PushResult with detailed status information
+ */
+export async function performPush(
+  worktreePath: string,
+  options?: PushOptions
+): Promise<PushResult> {
+  const targetRemote = options?.remote || 'origin';
+  const force = options?.force ?? false;
+  const autoResolve = options?.autoResolve ?? false;
+
+  // 1. Get current branch name
+  let branchName: string;
+  try {
+    branchName = await getCurrentBranch(worktreePath);
+  } catch (err) {
+    return {
+      success: false,
+      error: `Failed to get current branch: ${getErrorMessage(err)}`,
+    };
+  }
+
+  // 2. Check for detached HEAD state
+  if (branchName === 'HEAD') {
+    return {
+      success: false,
+      error: 'Cannot push in detached HEAD state. Please checkout a branch first.',
+    };
+  }
+
+  // 3. Build push args (no -u flag; upstream is set in the fallback path only when needed)
+  const pushArgs = ['push', targetRemote, branchName];
+  if (force) {
+    pushArgs.push('--force');
+  }
+
+  // 4. Attempt push
+  try {
+    await execGitCommand(pushArgs, worktreePath);
+
+    return {
+      success: true,
+      branch: branchName,
+      pushed: true,
+      message: `Successfully pushed ${branchName} to ${targetRemote}`,
+    };
+  } catch (pushError: unknown) {
+    const err = pushError as { stderr?: string; stdout?: string; message?: string };
+    const errorOutput = `${err.stderr || ''} ${err.stdout || ''} ${err.message || ''}`;
+
+    // 5. Check if the error is a divergence rejection
+    if (isDivergenceError(errorOutput)) {
+      if (!autoResolve) {
+        return {
+          success: false,
+          branch: branchName,
+          pushed: false,
+          diverged: true,
+          error: `Push rejected: remote has changes not present locally. Use sync or pull first, or enable auto-resolve.`,
+          message: `Push to ${targetRemote} was rejected because the remote branch has diverged.`,
+        };
+      }
+
+      // 6. Auto-resolve: pull then retry push
+      logger.info('Push rejected due to divergence, attempting auto-resolve via pull', {
+        worktreePath,
+        remote: targetRemote,
+        branch: branchName,
+      });
+
+      try {
+        const pullResult = await performPull(worktreePath, {
+          remote: targetRemote,
+          stashIfNeeded: true,
+        });
+
+        if (!pullResult.success) {
+          return {
+            success: false,
+            branch: branchName,
+            pushed: false,
+            diverged: true,
+            autoResolved: false,
+            error: `Auto-resolve failed during pull: ${pullResult.error}`,
+          };
+        }
+
+        if (pullResult.hasConflicts) {
+          return {
+            success: false,
+            branch: branchName,
+            pushed: false,
+            diverged: true,
+            autoResolved: false,
+            hasConflicts: true,
+            conflictFiles: pullResult.conflictFiles,
+            error:
+              'Auto-resolve pull resulted in merge conflicts. Resolve conflicts and push again.',
+          };
+        }
+
+        // 7. Retry push after successful pull
+        try {
+          await execGitCommand(pushArgs, worktreePath);
+
+          return {
+            success: true,
+            branch: branchName,
+            pushed: true,
+            diverged: true,
+            autoResolved: true,
+            message: `Push succeeded after auto-resolving divergence (pulled from ${targetRemote} first).`,
+          };
+        } catch (retryError: unknown) {
+          const retryErr = retryError as { stderr?: string; message?: string };
+          return {
+            success: false,
+            branch: branchName,
+            pushed: false,
+            diverged: true,
+            autoResolved: false,
+            error: `Push failed after auto-resolve pull: ${retryErr.stderr || retryErr.message || 'Unknown error'}`,
+          };
+        }
+      } catch (pullError) {
+        return {
+          success: false,
+          branch: branchName,
+          pushed: false,
+          diverged: true,
+          autoResolved: false,
+          error: `Auto-resolve pull failed: ${getErrorMessage(pullError)}`,
+        };
+      }
+    }
+
+    // 6b. Non-divergence error (e.g. no upstream configured) - retry with --set-upstream
+    const isNoUpstreamError =
+      errorOutput.toLowerCase().includes('no upstream') ||
+      errorOutput.toLowerCase().includes('has no upstream branch') ||
+      errorOutput.toLowerCase().includes('set-upstream');
+    if (isNoUpstreamError) {
+      try {
+        const setUpstreamArgs = ['push', '--set-upstream', targetRemote, branchName];
+        if (force) {
+          setUpstreamArgs.push('--force');
+        }
+        await execGitCommand(setUpstreamArgs, worktreePath);
+
+        return {
+          success: true,
+          branch: branchName,
+          pushed: true,
+          message: `Successfully pushed ${branchName} to ${targetRemote} (set upstream)`,
+        };
+      } catch (upstreamError: unknown) {
+        const upstreamErr = upstreamError as { stderr?: string; message?: string };
+        return {
+          success: false,
+          branch: branchName,
+          pushed: false,
+          error: upstreamErr.stderr || upstreamErr.message || getErrorMessage(pushError),
+        };
+      }
+    }
+
+    // 6c. Other push error - return as-is
+    return {
+      success: false,
+      branch: branchName,
+      pushed: false,
+      error: err.stderr || err.message || getErrorMessage(pushError),
+    };
+  }
+}

apps/server/src/services/sync-service.ts

@@ -0,0 +1,209 @@
+/**
+ * SyncService - Pull then push in a single operation
+ *
+ * Composes performPull() and performPush() to synchronize a branch
+ * with its remote. Always uses stashIfNeeded for the pull step.
+ * If push fails with divergence after pull, retries once.
+ *
+ * Follows the same pattern as pull-service.ts and push-service.ts.
+ */
+
+import { createLogger, getErrorMessage } from '@automaker/utils';
+import { performPull } from './pull-service.js';
+import { performPush } from './push-service.js';
+import type { PullResult } from './pull-service.js';
+import type { PushResult } from './push-service.js';
+
+const logger = createLogger('SyncService');
+
+// ============================================================================
+// Types
+// ============================================================================
+
+export interface SyncOptions {
+  /** Remote name (defaults to 'origin') */
+  remote?: string;
+}
+
+export interface SyncResult {
+  success: boolean;
+  error?: string;
+  branch?: string;
+  /** Whether the pull step was performed */
+  pulled?: boolean;
+  /** Whether the push step was performed */
+  pushed?: boolean;
+  /** Pull resulted in conflicts */
+  hasConflicts?: boolean;
+  /** Files with merge conflicts */
+  conflictFiles?: string[];
+  /** Source of conflicts ('pull' | 'stash') */
+  conflictSource?: 'pull' | 'stash';
+  /** Whether the pull was a fast-forward */
+  isFastForward?: boolean;
+  /** Whether the pull resulted in a merge commit */
+  isMerge?: boolean;
+  /** Whether push divergence was auto-resolved */
+  autoResolved?: boolean;
+  message?: string;
+}
+
+// ============================================================================
+// Main Service Function
+// ============================================================================
+
+/**
+ * Perform a sync operation (pull then push) on the given worktree.
+ *
+ * The workflow:
+ * 1. Pull from remote with stashIfNeeded: true
+ * 2. If pull has conflicts, stop and return conflict info
+ * 3. Push to remote
+ * 4. If push fails with divergence after pull, retry once
+ *
+ * @param worktreePath - Path to the git worktree
+ * @param options - Sync options (remote)
+ * @returns SyncResult with detailed status information
+ */
+export async function performSync(
+  worktreePath: string,
+  options?: SyncOptions
+): Promise<SyncResult> {
+  const targetRemote = options?.remote || 'origin';
+
+  // 1. Pull from remote
+  logger.info('Sync: starting pull', { worktreePath, remote: targetRemote });
+
+  let pullResult: PullResult;
+  try {
+    pullResult = await performPull(worktreePath, {
+      remote: targetRemote,
+      stashIfNeeded: true,
+    });
+  } catch (pullError) {
+    return {
+      success: false,
+      error: `Sync pull failed: ${getErrorMessage(pullError)}`,
+    };
+  }
+
+  if (!pullResult.success) {
+    return {
+      success: false,
+      branch: pullResult.branch,
+      pulled: false,
+      pushed: false,
+      error: `Sync pull failed: ${pullResult.error}`,
+      hasConflicts: pullResult.hasConflicts,
+      conflictFiles: pullResult.conflictFiles,
+      conflictSource: pullResult.conflictSource,
+    };
+  }
+
+  // 2. If pull had conflicts, stop and return conflict info
+  if (pullResult.hasConflicts) {
+    return {
+      success: false,
+      branch: pullResult.branch,
+      pulled: true,
+      pushed: false,
+      hasConflicts: true,
+      conflictFiles: pullResult.conflictFiles,
+      conflictSource: pullResult.conflictSource,
+      isFastForward: pullResult.isFastForward,
+      isMerge: pullResult.isMerge,
+      error: 'Sync stopped: pull resulted in merge conflicts. Resolve conflicts and try again.',
+      message: pullResult.message,
+    };
+  }
+
+  // 3. Push to remote
+  logger.info('Sync: pull succeeded, starting push', { worktreePath, remote: targetRemote });
+
+  let pushResult: PushResult;
+  try {
+    pushResult = await performPush(worktreePath, {
+      remote: targetRemote,
+    });
+  } catch (pushError) {
+    return {
+      success: false,
+      branch: pullResult.branch,
+      pulled: true,
+      pushed: false,
+      isFastForward: pullResult.isFastForward,
+      isMerge: pullResult.isMerge,
+      error: `Sync push failed: ${getErrorMessage(pushError)}`,
+    };
+  }
+
+  if (!pushResult.success) {
+    // 4. If push diverged after pull, retry once with autoResolve
+    if (pushResult.diverged) {
+      logger.info('Sync: push diverged after pull, retrying with autoResolve', {
+        worktreePath,
+        remote: targetRemote,
+      });
+
+      try {
+        const retryResult = await performPush(worktreePath, {
+          remote: targetRemote,
+          autoResolve: true,
+        });
+
+        if (retryResult.success) {
+          return {
+            success: true,
+            branch: retryResult.branch,
+            pulled: true,
+            pushed: true,
+            autoResolved: true,
+            isFastForward: pullResult.isFastForward,
+            isMerge: pullResult.isMerge,
+            message: 'Sync completed (push required auto-resolve).',
+          };
+        }
+
+        return {
+          success: false,
+          branch: retryResult.branch,
+          pulled: true,
+          pushed: false,
+          hasConflicts: retryResult.hasConflicts,
+          conflictFiles: retryResult.conflictFiles,
+          error: retryResult.error,
+        };
+      } catch (retryError) {
+        return {
+          success: false,
+          branch: pullResult.branch,
+          pulled: true,
+          pushed: false,
+          error: `Sync push retry failed: ${getErrorMessage(retryError)}`,
+        };
+      }
+    }
+
+    return {
+      success: false,
+      branch: pushResult.branch,
+      pulled: true,
+      pushed: false,
+      isFastForward: pullResult.isFastForward,
+      isMerge: pullResult.isMerge,
+      error: `Sync push failed: ${pushResult.error}`,
+    };
+  }
+
+  return {
+    success: true,
+    branch: pushResult.branch,
+    pulled: pullResult.pulled ?? true,
+    pushed: true,
+    isFastForward: pullResult.isFastForward,
+    isMerge: pullResult.isMerge,
+    message: pullResult.pulled
+      ? 'Sync completed: pulled latest changes and pushed.'
+      : 'Sync completed: already up to date, pushed local commits.',
+  };
+}