fix(js-sdk): don't treat "detached" in a branch name as a detached HEAD

.changeset/js-git-status-detached-substring.md

@@ -0,0 +1,5 @@
+---
+"e2b": patch
+---
+
+Fix `parseGitStatus` so a branch or upstream whose name merely contains the substring `detached` (for example `main` tracking `origin/detached-work`) is no longer misreported as a detached HEAD. Detached-HEAD detection now keys off the `HEAD (detached at <sha>)` / `HEAD (no branch)` porcelain forms only, so `currentBranch` and `upstream` are preserved. This mirrors the Python SDK fix for the same defect (#1373).

packages/js-sdk/src/sandbox/git/utils.ts

@@ -381,9 +381,7 @@ export function parseGitStatus(output: string): GitStatus {
       aheadStart === -1 ? undefined : branchInfo.slice(aheadStart + 2, -1)
     const normalizedBranch = normalizeBranchName(branchPart)
     const rawBranch = branchPart
-    const isDetached =
-      rawBranch.startsWith('HEAD (detached at ') ||
-      rawBranch.includes('detached')
+    const isDetached = rawBranch.startsWith('HEAD (detached at ')
 
     if (isDetached || normalizedBranch.startsWith('HEAD')) {
       detached = true

packages/js-sdk/tests/git.parseStatus.test.ts

@@ -0,0 +1,31 @@
+import { expect, test } from 'vitest'
+
+import { parseGitStatus } from '../src/sandbox/git/utils'
+
+// Twin of the Python fix in PR #1374 (issue #1373): `parseGitStatus` used to flag
+// `detached: true` for any branch/upstream name merely containing the substring
+// "detached", dropping `currentBranch`/`upstream` for ordinary branches.
+
+test('upstream whose name contains "detached" is not a detached HEAD', () => {
+  // Branch 'main' tracking 'origin/detached-work': NOT a detached HEAD.
+  const status = parseGitStatus('## main...origin/detached-work\n')
+  expect(status.detached).toBe(false)
+  expect(status.currentBranch).toBe('main')
+  expect(status.upstream).toBe('origin/detached-work')
+})
+
+test('local branch whose name contains "detached" is not a detached HEAD', () => {
+  const status = parseGitStatus('## feature/detached-session-fix\n')
+  expect(status.detached).toBe(false)
+  expect(status.currentBranch).toBe('feature/detached-session-fix')
+})
+
+test('real detached HEAD ("## HEAD (no branch)") is still detected', () => {
+  const status = parseGitStatus('## HEAD (no branch)\n')
+  expect(status.detached).toBe(true)
+})
+
+test('real detached HEAD ("## HEAD (detached at <sha>)") is still detected', () => {
+  const status = parseGitStatus('## HEAD (detached at 1a2b3c4)\n')
+  expect(status.detached).toBe(true)
+})