Fix sandbox sync rollback on stash conflicts

Author: nicoalbanese

packages/sandbox/git.test.ts

@@ -46,6 +46,7 @@ describe("syncToRemotePreservingChanges", () => {
     const sandbox = createSandbox([
       result(),
       result({ stdout: " M file.ts\n" }),
+      result({ stdout: "original-head\n" }),
       result(),
       result(),
       result(),
@@ -57,6 +58,7 @@ describe("syncToRemotePreservingChanges", () => {
     expect(sandbox.commands).toEqual([
       "git fetch origin feature:refs/remotes/origin/feature",
       "git status --porcelain",
+      "git rev-parse HEAD",
       "git stash push --include-untracked -m open-agents-pre-commit-sync",
       "git reset --hard origin/feature",
       "git branch --set-upstream-to=origin/feature feature",
@@ -79,4 +81,42 @@ describe("syncToRemotePreservingChanges", () => {
       "git fetch origin feature:refs/remotes/origin/feature",
     ]);
   });
+
+  test("rolls back and restores local changes when stash restore conflicts after sync", async () => {
+    const sandbox = createSandbox([
+      result(),
+      result({ stdout: " M file.ts\n" }),
+      result({ stdout: "original-head\n" }),
+      result(),
+      result(),
+      result(),
+      result({
+        success: false,
+        exitCode: 1,
+        stderr: "CONFLICT (content): Merge conflict in file.ts\n",
+      }),
+      result(),
+      result(),
+      result(),
+    ]) as Sandbox & { commands: string[] };
+
+    await expect(
+      syncToRemotePreservingChanges(sandbox, "feature"),
+    ).rejects.toThrow(
+      "Failed to restore local changes after syncing remote branch",
+    );
+
+    expect(sandbox.commands).toEqual([
+      "git fetch origin feature:refs/remotes/origin/feature",
+      "git status --porcelain",
+      "git rev-parse HEAD",
+      "git stash push --include-untracked -m open-agents-pre-commit-sync",
+      "git reset --hard origin/feature",
+      "git branch --set-upstream-to=origin/feature feature",
+      "git stash pop",
+      "git reset --hard original-head",
+      "git clean -fd",
+      "git stash pop",
+    ]);
+  });
 });

packages/sandbox/git.ts

@@ -95,6 +95,33 @@ async function resetToFetchedRemoteBranch(
   }
 }
 
+async function getCurrentHead(sandbox: Sandbox): Promise<string> {
+  const headResult = await exec(sandbox, "git rev-parse HEAD", 10000);
+  if (!headResult.success) {
+    throw new Error(
+      `Failed to inspect current HEAD: ${commandOutput(headResult)}`,
+    );
+  }
+
+  return headResult.stdout.trim();
+}
+
+async function resetToCommit(sandbox: Sandbox, commit: string): Promise<void> {
+  const resetResult = await exec(sandbox, `git reset --hard ${commit}`, 10000);
+  if (!resetResult.success) {
+    throw new Error(
+      `Failed to restore original HEAD after sync failure: ${commandOutput(resetResult)}`,
+    );
+  }
+
+  const cleanResult = await exec(sandbox, "git clean -fd", 10000);
+  if (!cleanResult.success) {
+    throw new Error(
+      `Failed to clean worktree after sync failure: ${commandOutput(cleanResult)}`,
+    );
+  }
+}
+
 // ---- public functions ----
 
 /**
@@ -343,6 +370,8 @@ export async function syncToRemotePreservingChanges(
     return;
   }
 
+  const originalHead = await getCurrentHead(sandbox);
+
   const stashResult = await exec(
     sandbox,
     "git stash push --include-untracked -m open-agents-pre-commit-sync",
@@ -357,12 +386,21 @@ export async function syncToRemotePreservingChanges(
   try {
     await resetToFetchedRemoteBranch(sandbox, branch);
   } catch (error) {
+    await resetToCommit(sandbox, originalHead);
     await exec(sandbox, "git stash pop", 30000).catch(() => {});
     throw error;
   }
 
   const popResult = await exec(sandbox, "git stash pop", 30000);
   if (!popResult.success) {
+    await resetToCommit(sandbox, originalHead);
+    const restoreResult = await exec(sandbox, "git stash pop", 30000);
+    if (!restoreResult.success) {
+      throw new Error(
+        `Failed to restore local changes after rolling back sync failure: ${commandOutput(restoreResult)}`,
+      );
+    }
+
     throw new Error(
       `Failed to restore local changes after syncing remote branch: ${commandOutput(popResult)}`,
     );