From 7352385cc63f12317b0b7603c912afa743926965 Mon Sep 17 00:00:00 2001
From: SivanCola <32437197+SivanCola@users.noreply.github.com>
Date: Wed, 28 Oct 2026 10:29:45 +0800
Subject: [PATCH 1/3] fix(delegation): reserve ancestor copy admission before
 publication

Problem: Competing continuations could create two copies of one ancestor in
the same parent session, leaving later continuation ambiguous.

Root cause: The source ref lock ended before a newly allocated copy published
metadata, and each preparation acquired a different destination ref lock.

Fix: Reserve the canonical nearest-source and target-parent pair before
searching for copies. Transfer the reservation to the returned run's existing
release lifetime, and release it on failed preparation. Preserve independent
parents, sources, current-reference locks and persisted formats.

Verification: Real TaskTool publication interleavings and Store regressions;
exact old-owner overlay fails 9 named events with 5 controls. Root 240-package
coverage, delegation/sessionstore race, vet, pinned lint, make check,
actionlint and Windows/Linux compile-only checks pass. Windows named-step
inventory validation rejects missing package completion and skipped cases.

Refs #14025
---
 .github/workflows/ci.yml                      |  37 +++
 docs/SUBAGENT_COPY_ADMISSION.md               |  56 +++++
 .../delegation/ancestor_copy_admission.go     |  58 +++++
 .../ancestor_copy_admission_test.go           | 235 ++++++++++++++++++
 internal/runtime/delegation/subagent_store.go |  11 +-
 .../task_ancestor_copy_admission_test.go      |  95 +++++++
 .../14025-ancestor-copy-admission.md          |  15 ++
 7 files changed, 500 insertions(+), 7 deletions(-)
 create mode 100644 docs/SUBAGENT_COPY_ADMISSION.md
 create mode 100644 internal/runtime/delegation/ancestor_copy_admission.go
 create mode 100644 internal/runtime/delegation/ancestor_copy_admission_test.go
 create mode 100644 internal/runtime/delegation/task_ancestor_copy_admission_test.go
 create mode 100644 release-notes/studio/unreleased/14025-ancestor-copy-admission.md

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cd1f56f8d0..1629740b3b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -170,6 +170,43 @@ jobs:
         shell: pwsh
         run: Get-CimInstance Win32_Processor | Select-Object -ExpandProperty Name
 
+      - name: test (Windows ancestor copy admission)
+        if: env.RUN_STEPS == 'true' && runner.os == 'Windows' && github.event_name == 'pull_request'
+        timeout-minutes: 5
+        shell: bash
+        run: |
+          set -o pipefail
+          go test -count=1 -timeout=3m -json -run '^(TestAncestorCopyAdmission|TestTaskAncestorCopyAdmission)' ./internal/runtime/delegation | tee "$RUNNER_TEMP/ancestor-copy-admission.jsonl"
+          jq -se '
+            [.[] | select(.Test == null and .Action == "pass") | .Package] as $packages |
+            [.[] | select(.Test != null and .Action == "pass") | .Test] as $tests |
+            all(.[]; .Action != "skip" and .Action != "fail") and
+            (["reasonix/internal/runtime/delegation"] - $packages | length) == 0 and
+            (["TestAncestorCopyAdmissionCoversUnpublishedRun",
+              "TestAncestorCopyAdmissionCoversUnpublishedRun/continue_then_continue",
+              "TestAncestorCopyAdmissionCoversUnpublishedRun/continue_then_legacy",
+              "TestAncestorCopyAdmissionCoversUnpublishedRun/legacy_then_continue",
+              "TestAncestorCopyAdmissionCoversUnpublishedRun/legacy_then_legacy",
+              "TestAncestorCopyAdmissionAllowsDifferentParents",
+              "TestAncestorCopyAdmissionReleasesAbandonedPreparation",
+              "TestAncestorCopyAdmissionReleasesAfterInvalidCopy",
+              "TestAncestorCopyAdmissionAllowsDifferentSources",
+              "TestAncestorCopyAdmissionUsesNearestSourceIdentity",
+              "TestAncestorCopyAdmissionReleasesAfterBusyCurrentReference",
+              "TestTaskAncestorCopyAdmissionBeforeRunningMetadata",
+              "TestTaskAncestorCopyAdmissionBeforeRunningMetadata/continue_from",
+              "TestTaskAncestorCopyAdmissionBeforeRunningMetadata/fork_from"] - $tests | length) == 0
+          ' "$RUNNER_TEMP/ancestor-copy-admission.jsonl"
+
+      - name: upload Windows ancestor copy admission inventory
+        if: always() && env.RUN_STEPS == 'true' && runner.os == 'Windows' && github.event_name == 'pull_request'
+        uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7
+        with:
+          name: ancestor-copy-admission-windows-${{ github.run_attempt }}
+          path: ${{ runner.temp }}/ancestor-copy-admission.jsonl
+          if-no-files-found: error
+          retention-days: 7
+
       - name: test
         if: env.RUN_STEPS == 'true' && runner.os != 'Windows'
         env:
diff --git a/docs/SUBAGENT_COPY_ADMISSION.md b/docs/SUBAGENT_COPY_ADMISSION.md
new file mode 100644
index 0000000000..ba6537395f
--- /dev/null
+++ b/docs/SUBAGENT_COPY_ADMISSION.md
@@ -0,0 +1,56 @@
+---
+owner: @esengine
+backup: @SivanCola
+status: active
+reviewed: 2026-10-28
+---
+
+# Ancestor continuation admission / 祖先续跑准入
+
+## Behavior / 行为
+
+1. Within one `SubagentStore`, continuing an ancestor transcript reserves its
+   canonical nearest source and target parent session before searching for a
+   current-session copy. The reservation lasts until the returned run releases.
+2. A competing continuation for that pair is refused as already in progress,
+   including before the first copy publishes its `running` metadata. It MUST
+   NOT create another copy or make another provider request.
+3. `continue_from` and the accepted legacy `fork_from` input share this owner.
+   Referring to an older ancestor or its nearest lineage copy uses the same
+   reservation. Different target parents and different sources remain separate.
+4. Failed preparation and abandoned unpublished runs release their reservation.
+   After a completed run releases, another continuation reuses its persisted
+   copy. Direct current-reference continuation keeps its existing ref lock.
+
+1. 同一 `SubagentStore` 在查找当前会话副本前，按最近祖先来源和目标父会话预留续跑归属；预留随返回的 run 一起释放。
+2. 首份副本尚未发布 `running` 元数据时，同一组合的竞争续跑也会被拒绝；不得再创建副本或发起模型请求。
+3. `continue_from` 与兼容的旧 `fork_from` 输入共用此归属。较早祖先及其最近副本归一到同一来源；不同目标会话、不同来源保持独立。
+4. 准备失败或放弃未发布的 run 会释放预留。已完成 run 释放后，续跑复用原持久化副本；直接按当前副本引用续跑仍使用原引用锁。
+
+## Compatibility and limits / 兼容与边界
+
+| Boundary / 边界 | Contract / 合同 |
+| --- | --- |
+| Storage / 存储 | No metadata, transcript, status or schema change. / 不改变元数据、转录、状态或 schema。 |
+| Existing ambiguity / 既有歧义 | Multiple existing copies remain refused; no automatic selection or deletion. / 已有多个副本仍拒绝，不自动选择或删除。 |
+| Scope / 范围 | One Store instance; existing process-local locking contract. / 仅同一 Store 实例，沿用进程内锁合同。 |
+| Cross-version writers / 跨版本写入 | No cross-process or old-writer fence; old binaries retain their behavior. / 不提供跨进程或旧写入者隔离。 |
+| Recovery / 恢复 | No resume of failed/interrupted children, durable reservation or restart recovery. / 不恢复失败或中断子任务，不提供持久化预留与重启恢复。 |
+| Authority / 权限 | Tool permission, cancellation authority, provider prefix and tool schema are unchanged. / 工具权限、取消权限、模型前缀和工具 schema 不变。 |
+
+## Validation / 验证
+
+1. Store regressions hold an unpublished preparation, cover both input routes,
+   nearest-source aliases, independent parents/sources and release after errors.
+2. TaskTool regressions block the existing parent-destruction callback before
+   `MarkRunning` writes metadata. A competing call is refused; the first call
+   receives the real persisted source transcript and creates the only copy.
+3. These are local Store/TaskTool tests with a scripted provider, not a live
+   provider, full Boot, browser, crash/restart or physical-process-scope test.
+4. The Windows workflow requires every named regression and the package terminal
+   pass, with no skips. Local cross-compilation is not native Windows evidence.
+
+1. Store 回归保留未发布的准备结果，覆盖两种输入、最近来源别名、不同会话和来源，以及错误后的释放。
+2. TaskTool 回归在 `MarkRunning` 写元数据前阻塞既有父会话销毁检查回调。竞争调用被拒绝，首个调用读取真实持久化来源转录并创建唯一副本。
+3. 以上是本机 Store/TaskTool 与脚本 provider 验证，不是线上 provider、完整 Boot、浏览器、崩溃重启或物理进程范围验证。
+4. Windows 工作流要求全部指定测试及包终态通过且零跳过；本机交叉编译不等于 Windows 原生执行。
diff --git a/internal/runtime/delegation/ancestor_copy_admission.go b/internal/runtime/delegation/ancestor_copy_admission.go
new file mode 100644
index 0000000000..0238d26921
--- /dev/null
+++ b/internal/runtime/delegation/ancestor_copy_admission.go
@@ -0,0 +1,58 @@
+package delegation
+
+import (
+	"fmt"
+	"strings"
+)
+
+type ancestorCopyKey struct {
+	parent string
+	source string
+}
+
+// A copied run has no durable metadata until its caller publishes it. Reserve
+// the target-parent/source pair before looking for an existing copy, and keep
+// that reservation for the returned run's ordinary lifetime. The ref lock alone
+// cannot protect this gap because each preparation would mint a different ref.
+func (s *SubagentStore) prepareContinueFromAncestor(ref string, spec SubagentSpec) (*SubagentRun, error) {
+	source, err := s.nearestLineageSource(ref, spec)
+	if err != nil {
+		return nil, err
+	}
+	releaseCopy, err := s.reserveAncestorCopy(ancestorCopyKey{
+		parent: strings.TrimSpace(spec.ParentSession), source: source,
+	})
+	if err != nil {
+		return nil, err
+	}
+	run, err := s.prepareContinueFromSource(source, spec)
+	if err != nil {
+		releaseCopy()
+		return nil, err
+	}
+	releaseRun := run.release
+	run.release = func() {
+		if releaseRun != nil {
+			releaseRun()
+		}
+		releaseCopy()
+	}
+	return run, nil
+}
+
+func (s *SubagentStore) reserveAncestorCopy(key ancestorCopyKey) (func(), error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.copying[key] {
+		return nil, fmt.Errorf("subagent reference %q is already being continued in parent session %q; retry after it finishes", key.source, key.parent)
+	}
+	if s.copying == nil {
+		s.copying = make(map[ancestorCopyKey]bool)
+	}
+	s.copying[key] = true
+	return func() {
+		s.mu.Lock()
+		delete(s.copying, key)
+		s.mu.Unlock()
+	}, nil
+}
diff --git a/internal/runtime/delegation/ancestor_copy_admission_test.go b/internal/runtime/delegation/ancestor_copy_admission_test.go
new file mode 100644
index 0000000000..c0f8a01286
--- /dev/null
+++ b/internal/runtime/delegation/ancestor_copy_admission_test.go
@@ -0,0 +1,235 @@
+package delegation
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"reasonix/internal/contract/provider"
+	"reasonix/internal/state/sessionstore"
+)
+
+func ancestorCopyFixture(t *testing.T) (*SubagentStore, string, SubagentSpec) {
+	t.Helper()
+	dir := t.TempDir()
+	s := NewSubagentStore(filepath.Join(dir, "subagents"))
+	spec := testSubagentSpec(t, "review")
+	spec.ParentSession = "root"
+	source, err := s.PrepareFresh(spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer source.Release()
+	source.Session.Add(provider.Message{Role: provider.RoleUser, Content: "original transcript bytes"})
+	if err := s.SaveCompleted(source); err != nil {
+		t.Fatal(err)
+	}
+	saveTestBranchMeta(t, dir, "root", "")
+	saveTestBranchMeta(t, dir, "child", "root")
+	saveTestBranchMeta(t, dir, "sibling", "root")
+	spec.ParentSession = "child"
+	return s, source.Ref, spec
+}
+
+func TestAncestorCopyAdmissionCoversUnpublishedRun(t *testing.T) {
+	for _, firstLegacy := range []bool{false, true} {
+		for _, secondLegacy := range []bool{false, true} {
+			firstName, secondName := "continue", "continue"
+			if firstLegacy {
+				firstName = "legacy"
+			}
+			if secondLegacy {
+				secondName = "legacy"
+			}
+			t.Run(firstName+"_then_"+secondName, func(t *testing.T) {
+				s, source, spec := ancestorCopyFixture(t)
+				prepare := func(legacy bool) (*SubagentRun, error) {
+					if legacy {
+						return s.PrepareLegacyForkFrom(source, spec)
+					}
+					return s.PrepareContinue(source, spec)
+				}
+				first, err := prepare(firstLegacy)
+				if err != nil {
+					t.Fatal(err)
+				}
+				defer first.Release()
+				if _, err := os.Stat(s.metaPath(first.Ref)); !os.IsNotExist(err) {
+					t.Fatalf("preparation published metadata: %v", err)
+				}
+				second, err := prepare(secondLegacy)
+				if second != nil {
+					second.Release()
+				}
+				if err == nil || !strings.Contains(err.Error(), "already") {
+					t.Fatalf("second admission = %v; first copy has not been published", err)
+				}
+				if err := s.SaveCompleted(first); err != nil {
+					t.Fatal(err)
+				}
+				first.Release()
+				reused, err := prepare(secondLegacy)
+				if err != nil {
+					t.Fatal(err)
+				}
+				defer reused.Release()
+				if reused.Ref != first.Ref {
+					t.Fatalf("continued %s instead of original copy %s", reused.Ref, first.Ref)
+				}
+			})
+		}
+	}
+}
+
+func TestAncestorCopyAdmissionAllowsDifferentParents(t *testing.T) {
+	s, source, spec := ancestorCopyFixture(t)
+	first, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer first.Release()
+	spec.ParentSession = "sibling"
+	second, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatalf("independent target parent blocked: %v", err)
+	}
+	defer second.Release()
+	if first.Ref == second.Ref || second.Meta.ParentSession != "sibling" {
+		t.Fatal("independent target parent did not get its own copy")
+	}
+}
+
+func TestAncestorCopyAdmissionReleasesAbandonedPreparation(t *testing.T) {
+	s, source, spec := ancestorCopyFixture(t)
+	first, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	first.Release()
+	first.Release()
+	second, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatalf("abandoned preparation retained admission: %v", err)
+	}
+	defer second.Release()
+	if second.Ref == first.Ref {
+		t.Fatal("unpublished preparation was adopted as persisted state")
+	}
+}
+
+func TestAncestorCopyAdmissionReleasesAfterInvalidCopy(t *testing.T) {
+	s, source, spec := ancestorCopyFixture(t)
+	copy, err := s.PrepareFresh(spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	copy.Meta.ForkedFrom = source
+	if err := s.SaveFailed(copy); err != nil {
+		t.Fatal(err)
+	}
+	copy.Release()
+	if run, err := s.PrepareContinue(source, spec); err == nil || !strings.Contains(err.Error(), "failed") {
+		if run != nil {
+			run.Release()
+		}
+		t.Fatalf("failed existing copy admission = %v", err)
+	}
+	// Repair only the fixture, to check that the failed lookup released its
+	// transient reservation. Production does not recover failed transcripts.
+	meta, err := s.LoadMeta(copy.Ref)
+	if err != nil {
+		t.Fatal(err)
+	}
+	meta.Status = sessionstore.SubagentCompleted
+	if err := s.saveMeta(meta); err != nil {
+		t.Fatal(err)
+	}
+	run, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatalf("failed preparation retained admission: %v", err)
+	}
+	run.Release()
+}
+
+func TestAncestorCopyAdmissionAllowsDifferentSources(t *testing.T) {
+	s, source, spec := ancestorCopyFixture(t)
+	otherSpec := spec
+	otherSpec.ParentSession = "root"
+	other, err := s.PrepareFresh(otherSpec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := s.SaveCompleted(other); err != nil {
+		t.Fatal(err)
+	}
+	other.Release()
+	first, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer first.Release()
+	second, err := s.PrepareContinue(other.Ref, spec)
+	if err != nil {
+		t.Fatalf("different ancestor source was blocked: %v", err)
+	}
+	second.Release()
+}
+
+func TestAncestorCopyAdmissionUsesNearestSourceIdentity(t *testing.T) {
+	s, source, spec := ancestorCopyFixture(t)
+	child, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := s.SaveCompleted(child); err != nil {
+		t.Fatal(err)
+	}
+	child.Release()
+	saveTestBranchMeta(t, filepath.Dir(s.dir), "grandchild", "child")
+	spec.ParentSession = "grandchild"
+	first, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer first.Release()
+	second, err := s.PrepareContinue(child.Ref, spec)
+	if second != nil {
+		second.Release()
+	}
+	if err == nil || !strings.Contains(err.Error(), "already") {
+		t.Fatalf("alias of nearest ancestor bypassed admission: %v", err)
+	}
+}
+
+func TestAncestorCopyAdmissionReleasesAfterBusyCurrentReference(t *testing.T) {
+	s, source, spec := ancestorCopyFixture(t)
+	copy, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := s.SaveCompleted(copy); err != nil {
+		t.Fatal(err)
+	}
+	copy.Release()
+	direct, err := s.PrepareContinue(copy.Ref, spec)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer direct.Release()
+	if run, err := s.PrepareContinue(source, spec); err == nil || !strings.Contains(err.Error(), "already") {
+		if run != nil {
+			run.Release()
+		}
+		t.Fatalf("busy current copy admission = %v", err)
+	}
+	direct.Release()
+	viaAncestor, err := s.PrepareContinue(source, spec)
+	if err != nil {
+		t.Fatalf("busy-ref failure retained ancestor reservation: %v", err)
+	}
+	defer viaAncestor.Release()
+	if viaAncestor.Ref != copy.Ref {
+		t.Fatal("ancestor retry created another copy")
+	}
+}
diff --git a/internal/runtime/delegation/subagent_store.go b/internal/runtime/delegation/subagent_store.go
index cb60c5f93a..843706b498 100644
--- a/internal/runtime/delegation/subagent_store.go
+++ b/internal/runtime/delegation/subagent_store.go
@@ -85,8 +85,9 @@ type SubagentStore struct {
 	// cleanupBeforeReread is a test seam for deterministic lease interleavings.
 	cleanupBeforeReread func(parentSession, ref string)
 
-	mu     sync.Mutex
-	locked map[string]bool
+	mu      sync.Mutex
+	locked  map[string]bool
+	copying map[ancestorCopyKey]bool
 	// live holds the conversation of every run this process is executing, so a
 	// reader sees a child while it works: its file is written only at the end.
 	live  map[string]*liveRun
@@ -376,11 +377,7 @@ func (s *SubagentStore) PrepareLegacyForkFrom(ref string, spec SubagentSpec) (*S
 	return s.PrepareContinue(ref, spec)
 }
 
-func (s *SubagentStore) prepareContinueFromAncestor(sourceRef string, spec SubagentSpec) (*SubagentRun, error) {
-	sourceRef, err := s.nearestLineageSource(sourceRef, spec)
-	if err != nil {
-		return nil, err
-	}
+func (s *SubagentStore) prepareContinueFromSource(sourceRef string, spec SubagentSpec) (*SubagentRun, error) {
 	copies, err := s.compatibleCopiesFromSource(sourceRef, spec)
 	if err != nil {
 		return nil, err
diff --git a/internal/runtime/delegation/task_ancestor_copy_admission_test.go b/internal/runtime/delegation/task_ancestor_copy_admission_test.go
new file mode 100644
index 0000000000..bb34e40cde
--- /dev/null
+++ b/internal/runtime/delegation/task_ancestor_copy_admission_test.go
@@ -0,0 +1,95 @@
+package delegation
+
+import (
+	"context"
+	"path/filepath"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"reasonix/internal/contract/provider"
+	"reasonix/internal/contract/tool"
+	"reasonix/internal/runtime/agent"
+	"reasonix/internal/state/sessionstore"
+)
+
+func TestTaskAncestorCopyAdmissionBeforeRunningMetadata(t *testing.T) {
+	for _, route := range []string{"continue_from", "fork_from"} {
+		t.Run(route, func(t *testing.T) {
+			dir := t.TempDir()
+			store := NewSubagentStore(filepath.Join(dir, "subagents"))
+			prov := &mockProvider{name: "sub", chunks: []provider.Chunk{
+				{Type: provider.ChunkText, Text: "persisted source answer"},
+				{Type: provider.ChunkDone},
+			}}
+			task := NewTaskTool(prov, nil, tool.NewRegistry(), 20, 0, 0, 0, 0, "", "sys", nil, 0, "", "", nil).
+				WithTranscripts(store, t.TempDir(), "base-model", "base-effort")
+			rootCtx := agent.WithParentSession(context.Background(), "root")
+			out, err := task.Execute(rootCtx, []byte(`{"prompt":"source task"}`))
+			if err != nil {
+				t.Fatal(err)
+			}
+			source := subagentRefFromOutput(t, out)
+			saveTestBranchMeta(t, dir, "root", "")
+			saveTestBranchMeta(t, dir, "child", "root")
+
+			entered, release := make(chan struct{}), make(chan struct{})
+			var once sync.Once
+			unblock := func() { once.Do(func() { close(release) }) }
+			var probes atomic.Int32
+			// This existing host callback is consulted by MarkRunning before it
+			// publishes metadata, after the real TaskTool prepared its transcript.
+			store.WithDestroyedChecker(func(parent string) bool {
+				if parent == "child" && probes.Add(1) == 1 {
+					close(entered)
+					<-release
+				}
+				return false
+			})
+			childCtx := agent.WithParentSession(context.Background(), "child")
+			type result struct {
+				output string
+				err    error
+			}
+			done := make(chan result, 1)
+			go func() {
+				output, err := task.Execute(childCtx, []byte(`{"prompt":"first child","continue_from":"`+source+`"}`))
+				done <- result{output, err}
+			}()
+			defer unblock()
+			select {
+			case <-entered:
+			case <-time.After(10 * time.Second):
+				t.Fatal("first TaskTool call did not reach metadata publication")
+			}
+			_, secondErr := task.Execute(childCtx, []byte(`{"prompt":"competing child","`+route+`":"`+source+`"}`))
+			unblock()
+			first := <-done
+			if first.err != nil {
+				t.Fatalf("first TaskTool: %v", first.err)
+			}
+			if secondErr == nil || !strings.Contains(secondErr.Error(), "already") {
+				t.Errorf("second TaskTool admission = %v; want busy refusal", secondErr)
+			}
+			copies, err := sessionstore.ListSubagentsByParent(dir, "child")
+			if err != nil {
+				t.Fatal(err)
+			}
+			if len(copies) != 1 || copies[0].Ref != subagentRefFromOutput(t, first.output) {
+				t.Errorf("current-parent copies = %d; want only the first admitted run", len(copies))
+			}
+			if len(prov.requests) != 2 {
+				t.Errorf("provider requests = %d; want source and first child only", len(prov.requests))
+			}
+			found := false
+			for _, message := range prov.lastReq.Messages {
+				found = found || message.Content == "persisted source answer"
+			}
+			if !found {
+				t.Fatal("child did not receive the persisted source transcript")
+			}
+		})
+	}
+}
diff --git a/release-notes/studio/unreleased/14025-ancestor-copy-admission.md b/release-notes/studio/unreleased/14025-ancestor-copy-admission.md
new file mode 100644
index 0000000000..b6b0c0e569
--- /dev/null
+++ b/release-notes/studio/unreleased/14025-ancestor-copy-admission.md
@@ -0,0 +1,15 @@
+同一会话并发续跑祖先子任务时，不再重复创建尚未发布的转录副本。
+
+## 修复
+
+- 在现有 Store 内预留目标会话与祖先来源，覆盖首次复制到发布元数据之间的窗口。关联 #14025。
+- 竞争续跑返回忙碌提示；不同会话和来源仍独立，已完成副本继续复用，不改变存储格式或工具权限。关联 #14025。
+
+---
+
+<!-- lang:en -->
+
+## Fixed
+
+- Reserve ancestor continuation copies within one Store before metadata publication, preventing competing calls from creating duplicate transcripts. Refs #14025.
+- Busy continuations are refused; independent parents and sources remain separate. Completed copies are reused without storage-format or permission changes. Refs #14025.

From 8378f0834cad8e23c75843578c43bef5bab0ecfc Mon Sep 17 00:00:00 2001
From: SivanCola <32437197+SivanCola@users.noreply.github.com>
Date: Wed, 28 Oct 2026 11:03:31 +0800
Subject: [PATCH 2/3] fix(delegation): identify busy ancestor continuations and
 share Windows checks

---
 .../ancestor-copy-admission.json              | 24 ++++++
 .github/workflows/ci.yml                      | 32 ++------
 docs/SUBAGENT_COPY_ADMISSION.md               | 21 +++++
 .../delegation/ancestor_copy_admission.go     |  7 +-
 .../ancestor_copy_admission_test.go           |  6 +-
 internal/runtime/delegation/task.go           |  3 +
 .../task_ancestor_copy_admission_test.go      | 49 ++++++++++-
 .../14025-ancestor-copy-admission.md          |  2 +
 scripts/windows-concurrency-tests.mjs         | 81 +++++++++++++++++++
 scripts/windows-concurrency-tests.test.mjs    | 43 ++++++++++
 10 files changed, 238 insertions(+), 30 deletions(-)
 create mode 100644 .github/windows-concurrency/ancestor-copy-admission.json
 create mode 100644 scripts/windows-concurrency-tests.mjs
 create mode 100644 scripts/windows-concurrency-tests.test.mjs

diff --git a/.github/windows-concurrency/ancestor-copy-admission.json b/.github/windows-concurrency/ancestor-copy-admission.json
new file mode 100644
index 0000000000..1276933c99
--- /dev/null
+++ b/.github/windows-concurrency/ancestor-copy-admission.json
@@ -0,0 +1,24 @@
+[
+  {
+    "package": "reasonix/internal/runtime/delegation",
+    "tests": [
+      "TestAncestorCopyAdmissionCoversUnpublishedRun",
+      "TestAncestorCopyAdmissionCoversUnpublishedRun/continue_then_continue",
+      "TestAncestorCopyAdmissionCoversUnpublishedRun/continue_then_legacy",
+      "TestAncestorCopyAdmissionCoversUnpublishedRun/legacy_then_continue",
+      "TestAncestorCopyAdmissionCoversUnpublishedRun/legacy_then_legacy",
+      "TestAncestorCopyAdmissionAllowsDifferentParents",
+      "TestAncestorCopyAdmissionReleasesAbandonedPreparation",
+      "TestAncestorCopyAdmissionReleasesAfterInvalidCopy",
+      "TestAncestorCopyAdmissionAllowsDifferentSources",
+      "TestAncestorCopyAdmissionUsesNearestSourceIdentity",
+      "TestAncestorCopyAdmissionReleasesAfterBusyCurrentReference",
+      "TestTaskAncestorCopyAdmissionBeforeRunningMetadata",
+      "TestTaskAncestorCopyAdmissionBeforeRunningMetadata/continue_from",
+      "TestTaskAncestorCopyAdmissionBeforeRunningMetadata/fork_from",
+      "TestTaskAncestorCopyAdmissionReleasesUnstartedBackground",
+      "TestTaskAncestorCopyAdmissionReleasesUnstartedBackground/continue_from",
+      "TestTaskAncestorCopyAdmissionReleasesUnstartedBackground/fork_from"
+    ]
+  }
+]
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1629740b3b..2b4f2f8544 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -170,40 +170,20 @@ jobs:
         shell: pwsh
         run: Get-CimInstance Win32_Processor | Select-Object -ExpandProperty Name
 
-      - name: test (Windows ancestor copy admission)
+      - name: test (Windows concurrency contracts)
         if: env.RUN_STEPS == 'true' && runner.os == 'Windows' && github.event_name == 'pull_request'
         timeout-minutes: 5
         shell: bash
         run: |
-          set -o pipefail
-          go test -count=1 -timeout=3m -json -run '^(TestAncestorCopyAdmission|TestTaskAncestorCopyAdmission)' ./internal/runtime/delegation | tee "$RUNNER_TEMP/ancestor-copy-admission.jsonl"
-          jq -se '
-            [.[] | select(.Test == null and .Action == "pass") | .Package] as $packages |
-            [.[] | select(.Test != null and .Action == "pass") | .Test] as $tests |
-            all(.[]; .Action != "skip" and .Action != "fail") and
-            (["reasonix/internal/runtime/delegation"] - $packages | length) == 0 and
-            (["TestAncestorCopyAdmissionCoversUnpublishedRun",
-              "TestAncestorCopyAdmissionCoversUnpublishedRun/continue_then_continue",
-              "TestAncestorCopyAdmissionCoversUnpublishedRun/continue_then_legacy",
-              "TestAncestorCopyAdmissionCoversUnpublishedRun/legacy_then_continue",
-              "TestAncestorCopyAdmissionCoversUnpublishedRun/legacy_then_legacy",
-              "TestAncestorCopyAdmissionAllowsDifferentParents",
-              "TestAncestorCopyAdmissionReleasesAbandonedPreparation",
-              "TestAncestorCopyAdmissionReleasesAfterInvalidCopy",
-              "TestAncestorCopyAdmissionAllowsDifferentSources",
-              "TestAncestorCopyAdmissionUsesNearestSourceIdentity",
-              "TestAncestorCopyAdmissionReleasesAfterBusyCurrentReference",
-              "TestTaskAncestorCopyAdmissionBeforeRunningMetadata",
-              "TestTaskAncestorCopyAdmissionBeforeRunningMetadata/continue_from",
-              "TestTaskAncestorCopyAdmissionBeforeRunningMetadata/fork_from"] - $tests | length) == 0
-          ' "$RUNNER_TEMP/ancestor-copy-admission.jsonl"
+          node --test scripts/windows-concurrency-tests.test.mjs
+          node scripts/windows-concurrency-tests.mjs "$RUNNER_TEMP/concurrency-windows.jsonl"
 
-      - name: upload Windows ancestor copy admission inventory
+      - name: upload Windows concurrency inventory
         if: always() && env.RUN_STEPS == 'true' && runner.os == 'Windows' && github.event_name == 'pull_request'
         uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7
         with:
-          name: ancestor-copy-admission-windows-${{ github.run_attempt }}
-          path: ${{ runner.temp }}/ancestor-copy-admission.jsonl
+          name: concurrency-windows-${{ github.run_attempt }}
+          path: ${{ runner.temp }}/concurrency-windows.jsonl
           if-no-files-found: error
           retention-days: 7
 
diff --git a/docs/SUBAGENT_COPY_ADMISSION.md b/docs/SUBAGENT_COPY_ADMISSION.md
index ba6537395f..0bc134643a 100644
--- a/docs/SUBAGENT_COPY_ADMISSION.md
+++ b/docs/SUBAGENT_COPY_ADMISSION.md
@@ -27,6 +27,13 @@ reviewed: 2026-10-28
 3. `continue_from` 与兼容的旧 `fork_from` 输入共用此归属。较早祖先及其最近副本归一到同一来源；不同目标会话、不同来源保持独立。
 4. 准备失败或放弃未发布的 run 会释放预留。已完成 run 释放后，续跑复用原持久化副本；直接按当前副本引用续跑仍使用原引用锁。
 
+`errors.Is(err, ErrAncestorCopyBusy)` identifies the refusal through wrapping.
+TaskTool uses the existing `subagent.settling` answer code and preserves that
+sentinel; callers do not classify error prose.
+
+包装后的错误仍可用 `errors.Is(err, ErrAncestorCopyBusy)` 识别；TaskTool 使用既有
+`subagent.settling` 回答码并保留此标识，不解析错误文案。
+
 ## Compatibility and limits / 兼容与边界
 
 | Boundary / 边界 | Contract / 合同 |
@@ -54,3 +61,17 @@ reviewed: 2026-10-28
 2. TaskTool 回归在 `MarkRunning` 写元数据前阻塞既有父会话销毁检查回调。竞争调用被拒绝，首个调用读取真实持久化来源转录并创建唯一副本。
 3. 以上是本机 Store/TaskTool 与脚本 provider 验证，不是线上 provider、完整 Boot、浏览器、崩溃重启或物理进程范围验证。
 4. Windows 工作流要求全部指定测试及包终态通过且零跳过；本机交叉编译不等于 Windows 原生执行。
+
+A second TaskTool regression requests background execution without a job manager.
+Preparation succeeds, then normal completion abandons the unstarted run.
+No test calls `Release` for it; a foreground retry proves admission was freed.
+
+另一 TaskTool 回归在没有 job manager 时请求后台执行：准备成功后由正常结束路径
+放弃尚未启动的 run；测试不调用其 `Release`，前台重试证明预留已释放。
+
+The shared `scripts/windows-concurrency-tests.mjs` step reads additive,
+package-qualified inventories under `.github/windows-concurrency/`. This suite
+requires 17 named passes including parents. The broad smoke remains.
+
+共享脚本读取 `.github/windows-concurrency/` 中按包限定的独立清单；此套件要求含
+父测试的 17 个指定测试通过，保留 broad smoke。
diff --git a/internal/runtime/delegation/ancestor_copy_admission.go b/internal/runtime/delegation/ancestor_copy_admission.go
index 0238d26921..028e379cbf 100644
--- a/internal/runtime/delegation/ancestor_copy_admission.go
+++ b/internal/runtime/delegation/ancestor_copy_admission.go
@@ -1,10 +1,15 @@
 package delegation
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 )
 
+// ErrAncestorCopyBusy means this store already holds a continuation of the
+// same canonical source in the target parent. Callers may retry after release.
+var ErrAncestorCopyBusy = errors.New("ancestor continuation is already in progress")
+
 type ancestorCopyKey struct {
 	parent string
 	source string
@@ -44,7 +49,7 @@ func (s *SubagentStore) reserveAncestorCopy(key ancestorCopyKey) (func(), error)
 	s.mu.Lock()
 	defer s.mu.Unlock()
 	if s.copying[key] {
-		return nil, fmt.Errorf("subagent reference %q is already being continued in parent session %q; retry after it finishes", key.source, key.parent)
+		return nil, fmt.Errorf("%w: subagent reference %q in parent session %q; retry after it finishes", ErrAncestorCopyBusy, key.source, key.parent)
 	}
 	if s.copying == nil {
 		s.copying = make(map[ancestorCopyKey]bool)
diff --git a/internal/runtime/delegation/ancestor_copy_admission_test.go b/internal/runtime/delegation/ancestor_copy_admission_test.go
index c0f8a01286..a6fc98a073 100644
--- a/internal/runtime/delegation/ancestor_copy_admission_test.go
+++ b/internal/runtime/delegation/ancestor_copy_admission_test.go
@@ -1,6 +1,8 @@
 package delegation
 
 import (
+	"errors"
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -62,7 +64,7 @@ func TestAncestorCopyAdmissionCoversUnpublishedRun(t *testing.T) {
 				if second != nil {
 					second.Release()
 				}
-				if err == nil || !strings.Contains(err.Error(), "already") {
+				if !errors.Is(fmt.Errorf("caller: %w", err), ErrAncestorCopyBusy) {
 					t.Fatalf("second admission = %v; first copy has not been published", err)
 				}
 				if err := s.SaveCompleted(first); err != nil {
@@ -197,7 +199,7 @@ func TestAncestorCopyAdmissionUsesNearestSourceIdentity(t *testing.T) {
 	if second != nil {
 		second.Release()
 	}
-	if err == nil || !strings.Contains(err.Error(), "already") {
+	if !errors.Is(err, ErrAncestorCopyBusy) {
 		t.Fatalf("alias of nearest ancestor bypassed admission: %v", err)
 	}
 }
diff --git a/internal/runtime/delegation/task.go b/internal/runtime/delegation/task.go
index 61ee938e90..3090e256ee 100644
--- a/internal/runtime/delegation/task.go
+++ b/internal/runtime/delegation/task.go
@@ -593,6 +593,9 @@ func (t *TaskTool) runProfileSpec(ctx context.Context, spec ProfileExecSpec, exi
 	agent.AttachReviewReport(subReg, grant)
 	run, err := t.prepareTranscriptRunWithPrompt(withUpstream(ctx, spec.Context.Upstream), subReg, modelRef, effortRef, spec.Context.parentSession(ctx), execution, spec.Context.executionParent(execution), spec.Context.ContinueFrom, spec.Context.ForkFrom, spec.Worker.SystemPrompt, spec.Worker.Kind, spec.Worker.Name)
 	if err != nil {
+		if errors.Is(err, ErrAncestorCopyBusy) {
+			return "", fmt.Errorf("%s: %w", steerCode(ErrSubagentSettling), err)
+		}
 		return "", err
 	}
 	exit.run = run
diff --git a/internal/runtime/delegation/task_ancestor_copy_admission_test.go b/internal/runtime/delegation/task_ancestor_copy_admission_test.go
index bb34e40cde..dc5bced31e 100644
--- a/internal/runtime/delegation/task_ancestor_copy_admission_test.go
+++ b/internal/runtime/delegation/task_ancestor_copy_admission_test.go
@@ -2,6 +2,7 @@ package delegation
 
 import (
 	"context"
+	"errors"
 	"path/filepath"
 	"strings"
 	"sync"
@@ -70,7 +71,7 @@ func TestTaskAncestorCopyAdmissionBeforeRunningMetadata(t *testing.T) {
 			if first.err != nil {
 				t.Fatalf("first TaskTool: %v", first.err)
 			}
-			if secondErr == nil || !strings.Contains(secondErr.Error(), "already") {
+			if !errors.Is(secondErr, ErrAncestorCopyBusy) || !strings.HasPrefix(secondErr.Error(), "subagent.settling: ") {
 				t.Errorf("second TaskTool admission = %v; want busy refusal", secondErr)
 			}
 			copies, err := sessionstore.ListSubagentsByParent(dir, "child")
@@ -93,3 +94,49 @@ func TestTaskAncestorCopyAdmissionBeforeRunningMetadata(t *testing.T) {
 		})
 	}
 }
+
+func TestTaskAncestorCopyAdmissionReleasesUnstartedBackground(t *testing.T) {
+	for _, route := range []string{"continue_from", "fork_from"} {
+		t.Run(route, func(t *testing.T) {
+			dir := t.TempDir()
+			store := NewSubagentStore(filepath.Join(dir, "subagents"))
+			prov := &mockProvider{name: "sub", chunks: []provider.Chunk{
+				{Type: provider.ChunkText, Text: "persisted source answer"},
+				{Type: provider.ChunkDone},
+			}}
+			task := NewTaskTool(prov, nil, tool.NewRegistry(), 20, 0, 0, 0, 0, "", "sys", nil, 0, "", "", nil).
+				WithTranscripts(store, t.TempDir(), "base-model", "base-effort")
+			root := agent.WithParentSession(context.Background(), "root")
+			out, err := task.Execute(root, []byte(`{"prompt":"source task"}`))
+			if err != nil {
+				t.Fatal(err)
+			}
+			source := subagentRefFromOutput(t, out)
+			saveTestBranchMeta(t, dir, "root", "")
+			saveTestBranchMeta(t, dir, "child", "root")
+			child := agent.WithParentSession(context.Background(), "child")
+			// TaskTool prepares the transcript before looking up the job manager.
+			// With no manager, its normal completion owner abandons that run before
+			// MarkRunning or a provider call. The test never calls run.Release.
+			_, err = task.Execute(child, []byte(`{"prompt":"unstarted child","run_in_background":true,"`+route+`":"`+source+`"}`))
+			if err == nil || err.Error() != "background execution is not available in this context" {
+				t.Fatalf("unstarted background result = %v", err)
+			}
+			if len(prov.requests) != 1 {
+				t.Fatal("abandoned child reached the provider")
+			}
+			copies, err := sessionstore.ListSubagentsByParent(dir, "child")
+			if err != nil || len(copies) != 0 {
+				t.Fatalf("abandoned run published metadata: %v, %v", copies, err)
+			}
+			out, err = task.Execute(child, []byte(`{"prompt":"retry in foreground","`+route+`":"`+source+`"}`))
+			if err != nil {
+				t.Fatalf("normal abandonment retained the reservation: %v", err)
+			}
+			copies, err = sessionstore.ListSubagentsByParent(dir, "child")
+			if err != nil || len(copies) != 1 || copies[0].Ref != subagentRefFromOutput(t, out) || len(prov.requests) != 2 {
+				t.Fatalf("foreground retry: copies=%v error=%v requests=%d", copies, err, len(prov.requests))
+			}
+		})
+	}
+}
diff --git a/release-notes/studio/unreleased/14025-ancestor-copy-admission.md b/release-notes/studio/unreleased/14025-ancestor-copy-admission.md
index b6b0c0e569..3f0f7a3321 100644
--- a/release-notes/studio/unreleased/14025-ancestor-copy-admission.md
+++ b/release-notes/studio/unreleased/14025-ancestor-copy-admission.md
@@ -4,6 +4,7 @@
 
 - 在现有 Store 内预留目标会话与祖先来源，覆盖首次复制到发布元数据之间的窗口。关联 #14025。
 - 竞争续跑返回忙碌提示；不同会话和来源仍独立，已完成副本继续复用，不改变存储格式或工具权限。关联 #14025。
+- 忙碌拒绝保留可识别的错误标识；尚未启动的后台准备被放弃后，正常退出路径释放预留，允许前台重试。关联 #14025。
 
 ---
 
@@ -13,3 +14,4 @@
 
 - Reserve ancestor continuation copies within one Store before metadata publication, preventing competing calls from creating duplicate transcripts. Refs #14025.
 - Busy continuations are refused; independent parents and sources remain separate. Completed copies are reused without storage-format or permission changes. Refs #14025.
+- Busy refusals retain a typed error identity; normal exit releases an abandoned, unstarted background preparation so a foreground retry can proceed. Refs #14025.
diff --git a/scripts/windows-concurrency-tests.mjs b/scripts/windows-concurrency-tests.mjs
new file mode 100644
index 0000000000..7185a1028e
--- /dev/null
+++ b/scripts/windows-concurrency-tests.mjs
@@ -0,0 +1,81 @@
+// Focused Windows concurrency contracts live in additive, package-qualified
+// inventories. New regressions do not need another workflow step or verifier.
+import assert from 'node:assert/strict';
+import { closeSync, mkdirSync, openSync, readFileSync, readdirSync } from 'node:fs';
+import { dirname, join, resolve } from 'node:path';
+import { spawnSync } from 'node:child_process';
+import { fileURLToPath } from 'node:url';
+
+export function readInventory(directory) {
+  const files = readdirSync(directory).filter(name => name.endsWith('.json')).sort();
+  assert(files.length > 0, 'no Windows concurrency inventories');
+  const required = new Map();
+  for (const file of files) {
+    const groups = JSON.parse(readFileSync(join(directory, file), 'utf8'));
+    assert(Array.isArray(groups) && groups.length > 0, `${file}: empty inventory`);
+    for (const group of groups) {
+      assert(group && /^reasonix\/internal\/(?:[a-z0-9_]+\/)*[a-z0-9_]+$/.test(group.package), `${file}: invalid package`);
+      assert(Array.isArray(group.tests) && group.tests.length > 0, `${file}: empty tests`);
+      const tests = required.get(group.package) ?? new Set();
+      for (const test of group.tests) {
+        assert(typeof test === 'string' && /^Test[A-Za-z0-9_]+(?:\/[^\s]+)*$/.test(test), `${file}: invalid test`);
+        tests.add(test);
+      }
+      required.set(group.package, tests);
+    }
+  }
+  for (const tests of required.values()) {
+    for (const test of tests) assert(tests.has(test.split('/')[0]), `missing parent for ${test}`);
+  }
+  return required;
+}
+
+export function verifyInventory(required, raw) {
+  const passed = new Map();
+  const packages = new Set();
+  for (const line of raw.split(/\r?\n/).filter(line => line.trim())) {
+    const event = JSON.parse(line);
+    assert(required.has(event.Package), `unexpected package: ${event.Package}`);
+    assert(!['skip', 'fail'].includes(event.Action), `${event.Package}: ${event.Action}: ${event.Test ?? '(package)'}`);
+    if (event.Action !== 'pass') continue;
+    if (!event.Test) {
+      packages.add(event.Package);
+      continue;
+    }
+    const tests = passed.get(event.Package) ?? new Set();
+    assert(!tests.has(event.Test), `duplicate pass: ${event.Package}/${event.Test}`);
+    tests.add(event.Test);
+    passed.set(event.Package, tests);
+  }
+  let count = 0;
+  for (const [pkg, tests] of required) {
+    assert(packages.has(pkg), `missing package terminal: ${pkg}`);
+    for (const test of tests) {
+      assert(passed.get(pkg)?.has(test), `missing test: ${pkg}/${test}`);
+      count++;
+    }
+  }
+  return { requiredTests: count, packages: required.size };
+}
+
+function main() {
+  const root = resolve(dirname(fileURLToPath(import.meta.url)), '..');
+  const required = readInventory(join(root, '.github/windows-concurrency'));
+  const roots = [...new Set([...required.values()].flatMap(tests => [...tests].map(test => test.split('/')[0])))].sort();
+  const output = resolve(process.argv[2] ?? join(process.env.RUNNER_TEMP ?? '.', 'concurrency-windows.jsonl'));
+  mkdirSync(dirname(output), { recursive: true });
+  const fd = openSync(output, 'w');
+  let result;
+  try {
+    result = spawnSync('go', ['test', '-count=1', '-timeout=3m', '-json', '-run', `^(${roots.join('|')})$`, ...required.keys()], {
+      cwd: root, stdio: ['ignore', fd, 'inherit'],
+    });
+  } finally {
+    closeSync(fd);
+  }
+  assert(!result.error, result.error?.message);
+  assert.equal(result.status, 0, `go test failed (${result.signal ?? result.status}); see ${output}`);
+  console.log(JSON.stringify({ ...verifyInventory(required, readFileSync(output, 'utf8')), output }));
+}
+
+if (process.argv[1] && resolve(process.argv[1]) === fileURLToPath(import.meta.url)) main();
diff --git a/scripts/windows-concurrency-tests.test.mjs b/scripts/windows-concurrency-tests.test.mjs
new file mode 100644
index 0000000000..e774a2d389
--- /dev/null
+++ b/scripts/windows-concurrency-tests.test.mjs
@@ -0,0 +1,43 @@
+import assert from 'node:assert/strict';
+import { mkdtempSync, rmSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import test from 'node:test';
+import { readInventory, verifyInventory } from './windows-concurrency-tests.mjs';
+
+test('additive manifests keep package-qualified requirements', () => {
+  const dir = mkdtempSync(join(tmpdir(), 'concurrency-inventory-'));
+  try {
+    const a = 'reasonix/internal/first', b = 'reasonix/internal/second';
+    writeFileSync(join(dir, 'one.json'), JSON.stringify([{ package: a, tests: ['TestShared', 'TestShared/case'] }]));
+    writeFileSync(join(dir, 'two.json'), JSON.stringify([{ package: b, tests: ['TestShared'] }]));
+    const required = readInventory(dir);
+    const events = [
+      { Package: a, Action: 'pass', Test: 'TestShared/case' },
+      { Package: a, Action: 'pass', Test: 'TestShared' },
+      { Package: a, Action: 'pass' },
+      { Package: b, Action: 'pass', Test: 'TestShared' },
+      { Package: b, Action: 'pass' },
+    ];
+    const raw = values => values.map(value => JSON.stringify(value)).join('\r\n');
+    assert.deepEqual(verifyInventory(required, raw(events)), { requiredTests: 3, packages: 2 });
+    for (let i = 0; i < events.length; i++) {
+      assert.throws(() => verifyInventory(required, raw(events.filter((_, index) => index !== i))));
+      assert.throws(() => verifyInventory(required, raw(events.map((event, index) => index === i ? { ...event, Action: 'skip' } : event))));
+    }
+    assert.throws(() => verifyInventory(required, raw([...events, { Package: a, Action: 'fail' }])));
+    assert.throws(() => verifyInventory(required, raw([...events, events[0]])));
+    assert.throws(() => verifyInventory(required, '{'));
+    writeFileSync(join(dir, 'two.json'), JSON.stringify([{ package: b, tests: ['TestOrphan/case'] }]));
+    assert.throws(() => readInventory(dir));
+    writeFileSync(join(dir, 'two.json'), JSON.stringify([{ package: '../other', tests: ['TestShared'] }]));
+    assert.throws(() => readInventory(dir));
+    writeFileSync(join(dir, 'two.json'), '[]');
+    assert.throws(() => readInventory(dir));
+    rmSync(join(dir, 'one.json'));
+    rmSync(join(dir, 'two.json'));
+    assert.throws(() => readInventory(dir));
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});

From 382016dfe116aa8a14c923ac49bcc4f2e0f258bd Mon Sep 17 00:00:00 2001
From: SivanCola <32437197+SivanCola@users.noreply.github.com>
Date: Wed, 28 Oct 2026 14:18:44 +0800
Subject: [PATCH 3/3] fix(ci): avoid backtracking in concurrency inventory
 names

Problem: CodeQL reports exponential backtracking in the shared Windows
inventory test-name parser.
Root cause: repeated suffix groups can partition the same slash sequence.
Fix: accept the entire optional non-whitespace suffix once, preserving the
previous accepted language. Cover nested names and a long malformed suffix.
Verification: two Node tests pass; the original regex fails the bounded
regression while the existing contract test passes. Go and inventory bytes
are unchanged; prior exact-head Go qualification remains separate.
---
 scripts/windows-concurrency-tests.mjs      |  2 +-
 scripts/windows-concurrency-tests.test.mjs | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/scripts/windows-concurrency-tests.mjs b/scripts/windows-concurrency-tests.mjs
index 7185a1028e..0c39d21277 100644
--- a/scripts/windows-concurrency-tests.mjs
+++ b/scripts/windows-concurrency-tests.mjs
@@ -18,7 +18,7 @@ export function readInventory(directory) {
       assert(Array.isArray(group.tests) && group.tests.length > 0, `${file}: empty tests`);
       const tests = required.get(group.package) ?? new Set();
       for (const test of group.tests) {
-        assert(typeof test === 'string' && /^Test[A-Za-z0-9_]+(?:\/[^\s]+)*$/.test(test), `${file}: invalid test`);
+        assert(typeof test === 'string' && /^Test[A-Za-z0-9_]+(?:\/[^\s]+)?$/.test(test), `${file}: invalid test`);
         tests.add(test);
       }
       required.set(group.package, tests);
diff --git a/scripts/windows-concurrency-tests.test.mjs b/scripts/windows-concurrency-tests.test.mjs
index e774a2d389..fab3f327db 100644
--- a/scripts/windows-concurrency-tests.test.mjs
+++ b/scripts/windows-concurrency-tests.test.mjs
@@ -2,9 +2,30 @@ import assert from 'node:assert/strict';
 import { mkdtempSync, rmSync, writeFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
+import { spawnSync } from 'node:child_process';
 import test from 'node:test';
 import { readInventory, verifyInventory } from './windows-concurrency-tests.mjs';
 
+test('long invalid subtest suffix is rejected without repeated slash partitioning', () => {
+  const dir = mkdtempSync(join(tmpdir(), 'concurrency-inventory-'));
+  try {
+    const inventory = tests => JSON.stringify([{ package: 'reasonix/internal/example', tests }]);
+    const file = join(dir, 'names.json');
+    const valid = ['Test0', 'Test0/a/b', 'Test0/!/', 'Test0//'];
+    writeFileSync(file, inventory(valid));
+    assert.deepEqual([...readInventory(dir).values()][0], new Set(valid));
+    writeFileSync(file, inventory(['Test0', `Test0/${'!/'.repeat(10000)} `]));
+    const script = `import assert from 'node:assert/strict';
+      import { readInventory } from ${JSON.stringify(new URL('./windows-concurrency-tests.mjs', import.meta.url).href)};
+      assert.throws(() => readInventory(process.argv[1]), /invalid test/);`;
+    const result = spawnSync(process.execPath, ['--input-type=module', '-e', script, dir], { timeout: 5000, encoding: 'utf8' });
+    assert.ifError(result.error);
+    assert.equal(result.status, 0, result.stderr);
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
 test('additive manifests keep package-qualified requirements', () => {
   const dir = mkdtempSync(join(tmpdir(), 'concurrency-inventory-'));
   try {