feat(dev): move restart logic out to start script

Previously, if there was a syntax error or some other exception stopping the dev server from starting up, the file change listener would not get registered and the dev server would not restart.

In this new version, the dev server will restart even after a previous run failed to parse or threw an exception.

packages/app-dev/bin/start-development-server.js

@@ -6,6 +6,8 @@ import { installSourcemapsSupport } from "vite-node/source-map"
 
 const log = console.info
 
+const DEVELOPMENT_SERVER_ENTRYPOINT = "packages/app-dev/src/backend/start.ts"
+
 const createViteServer = async () => {
   const viteServer = await createServer({
     logLevel: "error",
@@ -70,21 +72,62 @@ const getStartModule = async (
   /** @type import("../src/backend/start") */
   // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
   const startModule = await viteNodeRunner.executeFile(
-    "packages/app-dev/src/backend/start.ts",
+    DEVELOPMENT_SERVER_ENTRYPOINT,
   )
 
   return startModule.default
 }
 
+const isWithinBoundary = (
+  /** @type import('vite').ModuleNode */ node,
+  /** @type Set<import('vite').ModuleNode> */ traversedModules,
+  /** @type Set<import('vite').ModuleNode> */ boundaryModules,
+) => {
+  if (traversedModules.has(node)) {
+    return false
+  }
+  traversedModules.add(node)
+
+  if (boundaryModules.has(node)) {
+    return true
+  }
+
+  for (const importer of node.importers) {
+    if (isWithinBoundary(importer, traversedModules, boundaryModules)) {
+      return true
+    }
+  }
+
+  return false
+}
+
 log(chalk.bold(`  Dassie${chalk.green("//dev")}\n`))
 log("  Starting development server...\n")
 
 const { viteServer, viteNodeServer } = await createViteServer()
 
 const start = await getStartModule(viteServer, viteNodeServer)
-let reactorPromise = start({ viteServer, viteNodeServer, restart })
+let reactorPromise = start({ viteServer, viteNodeServer })
 let isRestartInProgress = false
 
+viteServer.watcher.on("change", (/** @type string */ file) => {
+  const { moduleGraph } = viteServer
+
+  const entrypoint = `${process.cwd()}/${DEVELOPMENT_SERVER_ENTRYPOINT}`
+
+  const changedModules = moduleGraph.getModulesByFile(file)
+  const boundaryModules = moduleGraph.getModulesByFile(entrypoint)
+  if (!changedModules || !boundaryModules) return
+
+  /**@type Set<import('vite').ModuleNode> */
+  const traversedModules = new Set()
+  for (const module of changedModules) {
+    if (isWithinBoundary(module, traversedModules, boundaryModules)) {
+      restart()
+    }
+  }
+})
+
 function restart() {
   if (isRestartInProgress) return
   isRestartInProgress = true
@@ -97,9 +140,12 @@ function restart() {
     viteNodeServer.fetchCache = new Map()
 
     const start = await getStartModule(viteServer, viteNodeServer)
-    reactorPromise = start({ viteServer, viteNodeServer, restart })
-    isRestartInProgress = false
-  })().catch((/** @type unknown */ error) => {
-    console.error("error in development server", { error })
-  })
+    reactorPromise = start({ viteServer, viteNodeServer })
+  })()
+    .catch((/** @type unknown */ error) => {
+      console.error("error in development server", { error })
+    })
+    .finally(() => {
+      isRestartInProgress = false
+    })
 }

packages/app-dev/src/backend/actors/handle-file-change.ts

@@ -11,7 +11,6 @@ import {
 } from "../constants/entrypoints"
 import { vite as logger } from "../logger/instances"
 import { PeeringStateStore } from "../stores/peering-state"
-import { RestartCallbackUnconstructable } from "../unconstructables/restart-callback"
 import { ViteNodeServer } from "../unconstructables/vite-node-server"
 import { ViteServer } from "../unconstructables/vite-server"
 import { RunNodesActor } from "./run-nodes"
@@ -61,7 +60,6 @@ const areModulesWithinBoundary = (
 export const HandleFileChangeActor = (reactor: Reactor) => {
   const viteServer = reactor.use(ViteServer)
   const viteNodeServer = reactor.use(ViteNodeServer)
-  const restart = reactor.use(RestartCallbackUnconstructable)
   const peeringStateStore = reactor.use(PeeringStateStore)
   const runNodesActor = reactor.use(RunNodesActor)
 
@@ -86,7 +84,6 @@ export const HandleFileChangeActor = (reactor: Reactor) => {
           developmentServerBoundaryModules,
         )
       ) {
-        restart()
         return
       }
 

packages/app-dev/src/backend/start.ts

@@ -12,14 +12,12 @@ import { RegisterReactiveLoggerActor } from "./actors/register-reactive-logger"
 import { RunNodesActor } from "./actors/run-nodes"
 import { DebugUiServerActor } from "./actors/serve-debug-ui"
 import { ListenForRpcWebSocketActor } from "./actors/serve-rpc"
-import { RestartCallbackUnconstructable } from "./unconstructables/restart-callback"
 import { ViteNodeServer } from "./unconstructables/vite-node-server"
 import { ViteServer } from "./unconstructables/vite-server"
 
 export interface StartParameters {
   viteServer: ViteDevServer
   viteNodeServer: ViteNodeServerType
-  restart: () => void
 }
 
 const RootActor = () =>
@@ -39,15 +37,10 @@ const RootActor = () =>
     sig.run(CloseViteServerOnShutdownActor)
   })
 
-const start = async ({
-  viteServer,
-  viteNodeServer,
-  restart,
-}: StartParameters) => {
+const start = async ({ viteServer, viteNodeServer }: StartParameters) => {
   const reactor = createReactor()
   reactor.set(ViteServer, viteServer)
   reactor.set(ViteNodeServer, viteNodeServer)
-  reactor.set(RestartCallbackUnconstructable, restart)
   const startActor = reactor.use(RootActor)
   await startActor.run(reactor)
   return reactor