refactor(server): centralize task graph readiness (#840)

packages/server/src/tasks/execution-order.ts

@@ -1,5 +1,11 @@
 import type { Task, TaskStore } from "./types.js";
-import { buildChildrenMap, loadScopedTaskGraph, sortByPriorityThenCreated } from "./task-graph.js";
+import {
+  buildChildrenMap,
+  getTasksById,
+  isTaskExecutableInOrder,
+  loadScopedTaskGraph,
+  sortByPriorityThenCreated,
+} from "./task-graph.js";
 
 export interface ExecutionOrderResult {
   /** Tasks in execution order (done first, then pending) */
@@ -24,24 +30,13 @@ export async function computeExecutionOrder(
 ): Promise<ExecutionOrderResult> {
   const graph = await loadScopedTaskGraph(store, scopeId);
 
-  const simDone = new Set(graph.allTasks.filter((t) => t.status === "done").map((t) => t.id));
+  const simDone = new Set(graph.doneTaskIds);
   const remaining = new Set(
     graph.candidates
       .filter((t) => t.status === "open" || t.status === "in_progress")
       .map((t) => t.id),
   );
 
-  const isReady = (taskId: string): boolean => {
-    const task = graph.taskMap.get(taskId);
-    if (!task) return false;
-    const depsOk = task.deps.every((depId) => simDone.has(depId));
-    const children = (graph.childrenMap.get(taskId) ?? []).filter((c) =>
-      graph.candidateIds.has(c.id),
-    );
-    const childrenOk = children.every((c) => simDone.has(c.id));
-    return depsOk && childrenOk;
-  };
-
   const timeline: Task[] = [];
   const orderMap = new Map<string, number>();
   let orderIdx = 0;
@@ -56,9 +51,8 @@ export async function computeExecutionOrder(
 
   // Then pending tasks in execution order
   while (remaining.size > 0) {
-    const readyNow = [...remaining]
-      .filter(isReady)
-      .map((tid) => graph.taskMap.get(tid)!)
+    const readyNow = getTasksById(graph, remaining)
+      .filter((task) => isTaskExecutableInOrder(graph, task.id, simDone))
       .sort(sortByPriorityThenCreated);
 
     if (readyNow.length === 0) break;

packages/server/src/tasks/task-graph.ts

@@ -6,6 +6,7 @@ export interface TaskGraph {
   taskMap: Map<string, Task>;
   childrenMap: Map<string, Task[]>;
   candidateIds: Set<string>;
+  doneTaskIds: Set<string>;
 }
 
 type TaskGraphStore = Pick<TaskStore, "list" | "get" | "getDescendants">;
@@ -35,6 +36,47 @@ export function buildChildrenMap(tasks: Task[]): Map<string, Task[]> {
   return childrenMap;
 }
 
+export function isReadyTask(graph: TaskGraph, task: Task): boolean {
+  return (
+    task.status === "open" &&
+    areTaskDepsDone(graph, task, graph.doneTaskIds) &&
+    areTaskChildrenDone(graph, task.id, graph.doneTaskIds)
+  );
+}
+
+export function isBlockedTask(graph: TaskGraph, task: Task): boolean {
+  return (
+    task.status !== "draft" &&
+    task.status !== "done" &&
+    task.deps.length > 0 &&
+    !areTaskDepsDone(graph, task, graph.doneTaskIds)
+  );
+}
+
+export function isTaskExecutableInOrder(
+  graph: TaskGraph,
+  taskId: string,
+  completedTaskIds: Set<string>,
+): boolean {
+  const task = graph.taskMap.get(taskId);
+  return (
+    task !== undefined &&
+    areTaskDepsDone(graph, task, completedTaskIds) &&
+    areTaskChildrenDone(graph, task.id, completedTaskIds, { scoped: true })
+  );
+}
+
+export function getTasksById(graph: TaskGraph, taskIds: Iterable<string>): Task[] {
+  const tasks: Task[] = [];
+  for (const taskId of taskIds) {
+    const task = graph.taskMap.get(taskId);
+    if (task) {
+      tasks.push(task);
+    }
+  }
+  return tasks;
+}
+
 export async function loadScopedTaskGraph(
   store: TaskGraphStore,
   scopeId?: string,
@@ -48,9 +90,32 @@ export async function loadScopedTaskGraph(
     taskMap: buildTaskMap(allTasks),
     childrenMap: buildChildrenMap(allTasks),
     candidateIds: new Set(candidates.map((task) => task.id)),
+    doneTaskIds: new Set(allTasks.filter((task) => task.status === "done").map((task) => task.id)),
   };
 }
 
+function areTaskDepsDone(graph: TaskGraph, task: Task, completedTaskIds: Set<string>): boolean {
+  return task.deps.every((depId) => {
+    const dep = graph.taskMap.get(depId);
+    return dep !== undefined && completedTaskIds.has(depId);
+  });
+}
+
+function areTaskChildrenDone(
+  graph: TaskGraph,
+  taskId: string,
+  completedTaskIds: Set<string>,
+  options?: { scoped: boolean },
+): boolean {
+  const children = graph.childrenMap.get(taskId) ?? [];
+  return children.every((child) => {
+    if (options?.scoped === true && !graph.candidateIds.has(child.id)) {
+      return true;
+    }
+    return completedTaskIds.has(child.id);
+  });
+}
+
 async function loadScopedCandidates(
   store: TaskGraphStore,
   allTasks: Task[],

packages/server/src/tasks/task-store.ts

@@ -2,7 +2,12 @@ import { readdir, readFile, writeFile, mkdir, unlink } from "node:fs/promises";
 import { join } from "node:path";
 import { randomBytes } from "node:crypto";
 import type { Task, TaskStore, CreateTaskOptions, TaskStatus } from "./types.js";
-import { loadScopedTaskGraph, sortByPriorityThenCreated } from "./task-graph.js";
+import {
+  isBlockedTask,
+  isReadyTask,
+  loadScopedTaskGraph,
+  sortByPriorityThenCreated,
+} from "./task-graph.js";
 
 function generateId(): string {
   return randomBytes(4).toString("hex");
@@ -253,34 +258,14 @@ export class FileTaskStore implements TaskStore {
 
   async getReady(scopeId?: string): Promise<Task[]> {
     const graph = await loadScopedTaskGraph(this, scopeId);
-
-    const isReady = (task: Task): boolean => {
-      if (task.status !== "open") return false;
-      const depsReady = task.deps.every((depId) => {
-        const dep = graph.taskMap.get(depId);
-        return dep?.status === "done";
-      });
-      if (!depsReady) return false;
-      const children = graph.childrenMap.get(task.id) ?? [];
-      return children.every((c) => c.status === "done");
-    };
-
-    return graph.candidates.filter(isReady).sort(sortByPriorityThenCreated);
+    return graph.candidates
+      .filter((task) => isReadyTask(graph, task))
+      .sort(sortByPriorityThenCreated);
   }
 
   async getBlocked(scopeId?: string): Promise<Task[]> {
     const graph = await loadScopedTaskGraph(this, scopeId);
-
-    const isBlocked = (task: Task): boolean => {
-      if (task.status === "draft" || task.status === "done") return false;
-      if (task.deps.length === 0) return false;
-      return task.deps.some((depId) => {
-        const dep = graph.taskMap.get(depId);
-        return dep?.status !== "done";
-      });
-    };
-
-    return graph.candidates.filter(isBlocked);
+    return graph.candidates.filter((task) => isBlockedTask(graph, task));
   }
 
   async getClosed(scopeId?: string): Promise<Task[]> {