Add guarded dev restart handling

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/__tests__/dev-server-status.test.ts

@@ -0,0 +1,66 @@
+import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { afterEach, describe, expect, it } from "vitest";
+import { readPersistedDevServerStatus, toDevServerHealthStatus } from "../dev-server-status.js";
+
+const tempDirs = [];
+
+function createTempStatusFile(payload: unknown) {
+  const dir = mkdtempSync(path.join(os.tmpdir(), "paperclip-dev-status-"));
+  tempDirs.push(dir);
+  const filePath = path.join(dir, "dev-server-status.json");
+  writeFileSync(filePath, `${JSON.stringify(payload)}\n`, "utf8");
+  return filePath;
+}
+
+afterEach(() => {
+  for (const dir of tempDirs.splice(0)) {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+describe("dev server status helpers", () => {
+  it("reads and normalizes persisted supervisor state", () => {
+    const filePath = createTempStatusFile({
+      dirty: true,
+      lastChangedAt: "2026-03-20T12:00:00.000Z",
+      changedPathCount: 4,
+      changedPathsSample: ["server/src/app.ts", "packages/shared/src/index.ts"],
+      pendingMigrations: ["0040_restart_banner.sql"],
+      lastRestartAt: "2026-03-20T11:30:00.000Z",
+    });
+
+    expect(readPersistedDevServerStatus({ PAPERCLIP_DEV_SERVER_STATUS_FILE: filePath })).toEqual({
+      dirty: true,
+      lastChangedAt: "2026-03-20T12:00:00.000Z",
+      changedPathCount: 4,
+      changedPathsSample: ["server/src/app.ts", "packages/shared/src/index.ts"],
+      pendingMigrations: ["0040_restart_banner.sql"],
+      lastRestartAt: "2026-03-20T11:30:00.000Z",
+    });
+  });
+
+  it("derives waiting-for-idle health state", () => {
+    const health = toDevServerHealthStatus(
+      {
+        dirty: true,
+        lastChangedAt: "2026-03-20T12:00:00.000Z",
+        changedPathCount: 2,
+        changedPathsSample: ["server/src/app.ts"],
+        pendingMigrations: [],
+        lastRestartAt: "2026-03-20T11:30:00.000Z",
+      },
+      { autoRestartEnabled: true, activeRunCount: 3 },
+    );
+
+    expect(health).toMatchObject({
+      enabled: true,
+      restartRequired: true,
+      reason: "backend_changes",
+      autoRestartEnabled: true,
+      activeRunCount: 3,
+      waitingForIdle: true,
+    });
+  });
+});

server/src/__tests__/instance-settings-routes.test.ts

@@ -38,6 +38,7 @@ describe("instance settings routes", () => {
     });
     mockInstanceSettingsService.getExperimental.mockResolvedValue({
       enableIsolatedWorkspaces: false,
+      autoRestartDevServerWhenIdle: false,
     });
     mockInstanceSettingsService.updateGeneral.mockResolvedValue({
       id: "instance-settings-1",
@@ -49,6 +50,7 @@ describe("instance settings routes", () => {
       id: "instance-settings-1",
       experimental: {
         enableIsolatedWorkspaces: true,
+        autoRestartDevServerWhenIdle: false,
       },
     });
     mockInstanceSettingsService.listCompanyIds.mockResolvedValue(["company-1", "company-2"]);
@@ -64,7 +66,10 @@ describe("instance settings routes", () => {
 
     const getRes = await request(app).get("/api/instance/settings/experimental");
     expect(getRes.status).toBe(200);
-    expect(getRes.body).toEqual({ enableIsolatedWorkspaces: false });
+    expect(getRes.body).toEqual({
+      enableIsolatedWorkspaces: false,
+      autoRestartDevServerWhenIdle: false,
+    });
 
     const patchRes = await request(app)
       .patch("/api/instance/settings/experimental")
@@ -77,6 +82,24 @@ describe("instance settings routes", () => {
     expect(mockLogActivity).toHaveBeenCalledTimes(2);
   });
 
+  it("allows local board users to update guarded dev-server auto-restart", async () => {
+    const app = createApp({
+      type: "board",
+      userId: "local-board",
+      source: "local_implicit",
+      isInstanceAdmin: true,
+    });
+
+    await request(app)
+      .patch("/api/instance/settings/experimental")
+      .send({ autoRestartDevServerWhenIdle: true })
+      .expect(200);
+
+    expect(mockInstanceSettingsService.updateExperimental).toHaveBeenCalledWith({
+      autoRestartDevServerWhenIdle: true,
+    });
+  });
+
   it("allows local board users to read and update general settings", async () => {
     const app = createApp({
       type: "board",

server/src/dev-server-status.ts

@@ -0,0 +1,103 @@
+import { existsSync, readFileSync } from "node:fs";
+
+export type PersistedDevServerStatus = {
+  dirty: boolean;
+  lastChangedAt: string | null;
+  changedPathCount: number;
+  changedPathsSample: string[];
+  pendingMigrations: string[];
+  lastRestartAt: string | null;
+};
+
+export type DevServerHealthStatus = {
+  enabled: true;
+  restartRequired: boolean;
+  reason: "backend_changes" | "pending_migrations" | "backend_changes_and_pending_migrations" | null;
+  lastChangedAt: string | null;
+  changedPathCount: number;
+  changedPathsSample: string[];
+  pendingMigrations: string[];
+  autoRestartEnabled: boolean;
+  activeRunCount: number;
+  waitingForIdle: boolean;
+  lastRestartAt: string | null;
+};
+
+function normalizeStringArray(value: unknown): string[] {
+  if (!Array.isArray(value)) return [];
+  return value
+    .filter((entry): entry is string => typeof entry === "string")
+    .map((entry) => entry.trim())
+    .filter((entry) => entry.length > 0);
+}
+
+function normalizeTimestamp(value: unknown): string | null {
+  if (typeof value !== "string") return null;
+  const trimmed = value.trim();
+  return trimmed.length > 0 ? trimmed : null;
+}
+
+export function readPersistedDevServerStatus(
+  env: NodeJS.ProcessEnv = process.env,
+): PersistedDevServerStatus | null {
+  const filePath = env.PAPERCLIP_DEV_SERVER_STATUS_FILE?.trim();
+  if (!filePath || !existsSync(filePath)) return null;
+
+  try {
+    const raw = JSON.parse(readFileSync(filePath, "utf8")) as Record<string, unknown>;
+    const changedPathsSample = normalizeStringArray(raw.changedPathsSample).slice(0, 5);
+    const pendingMigrations = normalizeStringArray(raw.pendingMigrations);
+    const changedPathCountRaw = raw.changedPathCount;
+    const changedPathCount =
+      typeof changedPathCountRaw === "number" && Number.isFinite(changedPathCountRaw)
+        ? Math.max(0, Math.trunc(changedPathCountRaw))
+        : changedPathsSample.length;
+    const dirtyRaw = raw.dirty;
+    const dirty =
+      typeof dirtyRaw === "boolean"
+        ? dirtyRaw
+        : changedPathCount > 0 || pendingMigrations.length > 0;
+
+    return {
+      dirty,
+      lastChangedAt: normalizeTimestamp(raw.lastChangedAt),
+      changedPathCount,
+      changedPathsSample,
+      pendingMigrations,
+      lastRestartAt: normalizeTimestamp(raw.lastRestartAt),
+    };
+  } catch {
+    return null;
+  }
+}
+
+export function toDevServerHealthStatus(
+  persisted: PersistedDevServerStatus,
+  opts: { autoRestartEnabled: boolean; activeRunCount: number },
+): DevServerHealthStatus {
+  const hasPathChanges = persisted.changedPathCount > 0;
+  const hasPendingMigrations = persisted.pendingMigrations.length > 0;
+  const reason =
+    hasPathChanges && hasPendingMigrations
+      ? "backend_changes_and_pending_migrations"
+      : hasPendingMigrations
+        ? "pending_migrations"
+        : hasPathChanges
+          ? "backend_changes"
+          : null;
+  const restartRequired = persisted.dirty || reason !== null;
+
+  return {
+    enabled: true,
+    restartRequired,
+    reason,
+    lastChangedAt: persisted.lastChangedAt,
+    changedPathCount: persisted.changedPathCount,
+    changedPathsSample: persisted.changedPathsSample,
+    pendingMigrations: persisted.pendingMigrations,
+    autoRestartEnabled: opts.autoRestartEnabled,
+    activeRunCount: opts.activeRunCount,
+    waitingForIdle: restartRequired && opts.autoRestartEnabled && opts.activeRunCount > 0,
+    lastRestartAt: persisted.lastRestartAt,
+  };
+}

server/src/routes/health.ts

@@ -1,8 +1,10 @@
 import { Router } from "express";
 import type { Db } from "@paperclipai/db";
-import { and, count, eq, gt, isNull, sql } from "drizzle-orm";
-import { instanceUserRoles, invites } from "@paperclipai/db";
+import { and, count, eq, gt, inArray, isNull, sql } from "drizzle-orm";
+import { heartbeatRuns, instanceUserRoles, invites } from "@paperclipai/db";
 import type { DeploymentExposure, DeploymentMode } from "@paperclipai/shared";
+import { readPersistedDevServerStatus, toDevServerHealthStatus } from "../dev-server-status.js";
+import { instanceSettingsService } from "../services/instance-settings.js";
 import { serverVersion } from "../version.js";
 
 export function healthRoutes(
@@ -55,6 +57,23 @@ export function healthRoutes(
       }
     }
 
+    const persistedDevServerStatus = readPersistedDevServerStatus();
+    let devServer: ReturnType<typeof toDevServerHealthStatus> | undefined;
+    if (persistedDevServerStatus) {
+      const instanceSettings = instanceSettingsService(db);
+      const experimentalSettings = await instanceSettings.getExperimental();
+      const activeRunCount = await db
+        .select({ count: count() })
+        .from(heartbeatRuns)
+        .where(inArray(heartbeatRuns.status, ["queued", "running"]))
+        .then((rows) => Number(rows[0]?.count ?? 0));
+
+      devServer = toDevServerHealthStatus(persistedDevServerStatus, {
+        autoRestartEnabled: experimentalSettings.autoRestartDevServerWhenIdle ?? false,
+        activeRunCount,
+      });
+    }
+
     res.json({
       status: "ok",
       version: serverVersion,
@@ -66,6 +85,7 @@ export function healthRoutes(
       features: {
         companyDeletionEnabled: opts.companyDeletionEnabled,
       },
+      ...(devServer ? { devServer } : {}),
     });
   });
 

server/src/services/instance-settings.ts

@@ -30,10 +30,12 @@ function normalizeExperimentalSettings(raw: unknown): InstanceExperimentalSettin
   if (parsed.success) {
     return {
       enableIsolatedWorkspaces: parsed.data.enableIsolatedWorkspaces ?? false,
+      autoRestartDevServerWhenIdle: parsed.data.autoRestartDevServerWhenIdle ?? false,
     };
   }
   return {
     enableIsolatedWorkspaces: false,
+    autoRestartDevServerWhenIdle: false,
   };
 }