feat(arr): sequential merge and track pr linking

apps/cli/package.json

@@ -10,7 +10,6 @@
     "build": "bun build ./src/index.ts --outdir ./dist --target bun",
     "dev": "bun run ./bin/arr.ts",
     "typecheck": "tsc --noEmit",
-    "test": "bun test --concurrent tests/unit tests/e2e/cli.test.ts",
     "test:pty": "vitest run tests/e2e/pty.test.ts"
   },
   "devDependencies": {

apps/cli/src/commands/merge.ts

@@ -12,7 +12,6 @@ import {
   formatSuccess,
   hint,
   message,
-  status,
   warning,
 } from "../utils/output";
 import { unwrap } from "../utils/run";
@@ -24,8 +23,6 @@ interface MergeFlags {
 }
 
 export async function merge(flags: MergeFlags, ctx: ArrContext): Promise<void> {
-  const trunk = ctx.trunk;
-
   const prsResult = await getMergeablePrs();
 
   if (!prsResult.ok) {
@@ -62,25 +59,22 @@ export async function merge(flags: MergeFlags, ctx: ArrContext): Promise<void> {
   if (flags.merge) method = "merge";
   if (flags.rebase) method = "rebase";
 
-  message(`Merging ${prs.length} PR${prs.length > 1 ? "s" : ""} from stack...`);
+  message(`Merging ${prs.length} PR${prs.length > 1 ? "s" : ""}...`);
   blank();
 
   const result = await mergeCmd(prs, {
     method,
     engine: ctx.engine,
-    onMerging: (pr: PRToMerge, nextPr?: PRToMerge) => {
-      message(`Merging PR #${cyan(String(pr.prNumber))}: ${pr.prTitle}`);
-      hint(`Branch: ${pr.bookmarkName} → ${pr.baseRefName}`);
-      if (nextPr) {
-        hint(`Rebasing PR #${nextPr.prNumber} onto ${trunk}...`);
-      }
+    onWaitingForCI: (pr: PRToMerge) => {
+      message(`PR #${cyan(String(pr.prNumber))}: ${pr.prTitle}`);
+      message(dim("  Waiting for CI checks..."));
     },
-    onWaiting: () => {
-      process.stdout.write(dim("  Waiting for GitHub..."));
+    onMerging: (_pr: PRToMerge) => {
+      message(dim("  Merging..."));
     },
     onMerged: (pr: PRToMerge) => {
-      process.stdout.write(`\r${" ".repeat(30)}\r`);
-      message(formatSuccess(`Merged PR #${pr.prNumber}`));
+      message(formatSuccess(`  Merged PR #${pr.prNumber}`));
+      blank();
     },
   });
 
@@ -89,7 +83,10 @@ export async function merge(flags: MergeFlags, ctx: ArrContext): Promise<void> {
     process.exit(1);
   }
 
-  blank();
-  status("Syncing to update local state...");
-  message(formatSuccess("Done! All PRs merged and synced."));
+  message(
+    formatSuccess(
+      `Merged ${result.value.merged.length} PR${result.value.merged.length > 1 ? "s" : ""}!`,
+    ),
+  );
+  hint("Run 'arr sync' to update local state.");
 }

apps/cli/src/commands/track.ts

@@ -16,4 +16,7 @@ export async function track(
 
   message(formatSuccess(`Now tracking ${cyan(result.bookmark)}`));
   indent(`${dim("Parent:")} ${result.parent}`);
+  if (result.linkedPr) {
+    indent(`${dim("Linked:")} PR #${result.linkedPr}`);
+  }
 }

packages/core/src/commands/merge.ts

@@ -7,8 +7,8 @@ import type { Command } from "./types";
 interface MergeOptions {
   method?: "merge" | "squash" | "rebase";
   engine: Engine;
-  onMerging?: (pr: PRToMerge, nextPr?: PRToMerge) => void;
-  onWaiting?: () => void;
+  onWaitingForCI?: (pr: PRToMerge) => void;
+  onMerging?: (pr: PRToMerge) => void;
   onMerged?: (pr: PRToMerge) => void;
 }
 
@@ -20,7 +20,8 @@ export async function getMergeablePrs(): Promise<Result<PRToMerge[]>> {
 }
 
 /**
- * Merge the stack of PRs.
+ * Merge the stack of PRs sequentially.
+ * Waits for CI to pass on each PR before merging, then updates the next PR's base.
  * Untracks merged bookmarks from the engine.
  */
 export async function merge(
@@ -31,8 +32,8 @@ export async function merge(
     prs,
     { method: options.method ?? "squash", engine: options.engine },
     {
+      onWaitingForCI: options.onWaitingForCI,
       onMerging: options.onMerging,
-      onWaiting: options.onWaiting,
       onMerged: options.onMerged,
     },
   );

packages/core/src/commands/track.ts

@@ -1,4 +1,5 @@
 import type { Engine } from "../engine";
+import { getPRForBranch } from "../github/pr-status";
 import { ensureBookmark, getTrunk, list, resolveChange } from "../jj";
 import { createError, err, ok, type Result } from "../result";
 import { datePrefixedLabel } from "../slugify";
@@ -7,6 +8,8 @@ import type { Command } from "./types";
 interface TrackResult {
   bookmark: string;
   parent: string;
+  /** PR number if an existing PR was found and linked */
+  linkedPr?: number;
 }
 
 interface TrackOptions {
@@ -126,7 +129,14 @@ export async function track(
     return refreshResult;
   }
 
-  return ok({ bookmark, parent: parentBranch });
+  // Check if this bookmark has an existing PR on GitHub
+  let linkedPr: number | undefined;
+  const prResult = await getPRForBranch(bookmark);
+  if (prResult.ok && prResult.value && prResult.value.state === "OPEN") {
+    linkedPr = prResult.value.number;
+  }
+
+  return ok({ bookmark, parent: parentBranch, linkedPr });
 }
 
 export const trackCommand: Command<TrackResult, [TrackOptions]> = {

packages/core/src/github/pr-actions.ts

@@ -194,19 +194,31 @@ export async function updatePRBranch(
   }
 }
 
+export interface WaitForMergeableOptions {
+  timeoutMs?: number;
+  pollIntervalMs?: number;
+  /** Callback when status changes, for UI updates */
+  onStatusChange?: (status: {
+    mergeable: boolean | null;
+    state: string;
+    checksComplete: boolean;
+  }) => void;
+}
+
 export function waitForMergeable(
   prNumber: number,
-  options?: { timeoutMs?: number; pollIntervalMs?: number },
+  options?: WaitForMergeableOptions,
   cwd = process.cwd(),
 ): Promise<Result<{ mergeable: boolean; reason?: string }>> {
-  const timeoutMs = options?.timeoutMs ?? 30000;
-  const pollIntervalMs = options?.pollIntervalMs ?? 2000;
+  const timeoutMs = options?.timeoutMs ?? 300000; // 5 minutes default
+  const pollIntervalMs = options?.pollIntervalMs ?? 5000;
 
   return withGitHub(
     cwd,
     "check mergeable status",
     async ({ octokit, owner, repo }) => {
       const startTime = Date.now();
+      let lastState = "";
 
       while (Date.now() - startTime < timeoutMs) {
         const { data: pr } = await octokit.pulls.get({
@@ -215,23 +227,58 @@ export function waitForMergeable(
           pull_number: prNumber,
         });
 
-        if (pr.mergeable === true) {
+        // mergeable_state values:
+        // - "clean": can merge, all checks passed
+        // - "blocked": checks pending or required reviews missing
+        // - "dirty": has conflicts
+        // - "unstable": has failing checks but can still merge
+        // - "unknown": GitHub is computing
+        const state = pr.mergeable_state || "unknown";
+        const checksComplete = state !== "blocked" && state !== "unknown";
+
+        // Notify caller of status change
+        if (state !== lastState) {
+          options?.onStatusChange?.({
+            mergeable: pr.mergeable,
+            state,
+            checksComplete,
+          });
+          lastState = state;
+        }
+
+        // "clean" means mergeable AND all required checks passed
+        if (state === "clean" && pr.mergeable === true) {
           return { mergeable: true };
         }
 
-        if (pr.mergeable === false) {
+        // "unstable" means checks failed but PR is still mergeable (non-required checks)
+        if (state === "unstable" && pr.mergeable === true) {
+          return { mergeable: true };
+        }
+
+        // Has conflicts
+        if (state === "dirty") {
+          return {
+            mergeable: false,
+            reason: "Has merge conflicts",
+          };
+        }
+
+        // Explicit not mergeable
+        if (pr.mergeable === false && state !== "unknown") {
           return {
             mergeable: false,
-            reason: pr.mergeable_state || "Has conflicts or other issues",
+            reason: state || "Not mergeable",
           };
         }
 
+        // "blocked" or "unknown" - keep waiting
         await new Promise((resolve) => setTimeout(resolve, pollIntervalMs));
       }
 
       return {
         mergeable: false,
-        reason: "Timeout waiting for merge status",
+        reason: "Timeout waiting for CI checks",
       };
     },
   );

packages/core/src/result.ts

@@ -33,6 +33,7 @@ export type JJErrorCode =
   | "ALREADY_MERGED"
   | "NOT_FOUND"
   | "EMPTY_CHANGE"
+  | "CI_FAILED"
   | "UNKNOWN";
 
 export function createError(