From 737e9852e49dd0e5478c9fe7a6d6fc33ee1d4fca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Pierzcha=C5=82a?= <thymikee@gmail.com>
Date: Thu, 8 Oct 2026 10:40:26 +0200
Subject: [PATCH 1/6] refactor(graph): use shared engine for gate traversals

---
 scripts/depgraph/import-graph.ts              |  34 +++-
 scripts/depgraph/model.ts                     |   3 +-
 scripts/fuzz/envelope.test.ts                 |  37 ++--
 .../daemon-platform-runtime-inventory.ts      |  24 +--
 scripts/layering/model.ts                     | 172 +++++-------------
 ...vider-snapshot-presentation-policy.test.ts |  35 ++++
 .../provider-snapshot-presentation-policy.ts  |  14 +-
 scripts/mutation/ownership.test.ts            |  10 +-
 scripts/mutation/ownership.ts                 |  70 +++----
 9 files changed, 197 insertions(+), 202 deletions(-)

diff --git a/scripts/depgraph/import-graph.ts b/scripts/depgraph/import-graph.ts
index b3cb50ffac..25a731b5ee 100644
--- a/scripts/depgraph/import-graph.ts
+++ b/scripts/depgraph/import-graph.ts
@@ -3,7 +3,8 @@
 // a graph built here, so a kind filter is the only thing that distinguishes their subgraphs.
 
 import { createGraph, type Graph } from '@statelyai/graph';
-import type { EdgeKind, GraphEdge } from './model.ts';
+
+export type EdgeKind = 'value' | 'type' | 'dynamic';
 
 /** The subgraph R4 keeps acyclic: what a module needs before it can evaluate. */
 export const VALUE_EDGES: ReadonlySet<EdgeKind> = new Set(['value']);
@@ -14,6 +15,7 @@ export const VALUE_EDGES: ReadonlySet<EdgeKind> = new Set(['value']);
  * dynamic edges would cut every handler chain at its root.
  */
 export const EXECUTABLE_EDGES: ReadonlySet<EdgeKind> = new Set(['value', 'dynamic']);
+export const STATIC_EDGES: ReadonlySet<EdgeKind> = new Set(['value', 'type']);
 
 /**
  * Every collapsed edge kind, for the structural question ("does anything reference this file at
@@ -24,6 +26,15 @@ export const EXECUTABLE_EDGES: ReadonlySet<EdgeKind> = new Set(['value', 'dynami
  */
 export const ALL_EDGES: ReadonlySet<EdgeKind> = new Set(['value', 'type', 'dynamic']);
 
+type ImportGraphEdge = { from: string; to: string; kind: EdgeKind };
+
+type ResolvedGraphEdge = {
+  file: string;
+  target: string;
+  dynamic: boolean;
+  typeOnly: boolean;
+};
+
 /**
  * Identity of one file pair, shared by `collapseEdges` and the graph's edge ids. NUL cannot occur
  * in a file path, so distinct pairs never share an id.
@@ -37,7 +48,7 @@ export function importEdgeId(from: string, to: string): string {
  * isolated modules still exist as nodes.
  */
 export function importGraph(
-  edges: readonly GraphEdge[],
+  edges: readonly ImportGraphEdge[],
   kinds: ReadonlySet<EdgeKind>,
   files: Iterable<string> = [],
 ): Graph {
@@ -56,3 +67,22 @@ export function importGraph(
     })),
   });
 }
+
+/** Build a traversal graph from the normalized edges produced by the layering model. */
+export function importGraphFromResolvedEdges(
+  edges: readonly ResolvedGraphEdge[],
+  kinds: ReadonlySet<EdgeKind>,
+  files: Iterable<string> = [],
+): Graph {
+  const seen = new Set<string>();
+  const graphEdges: ImportGraphEdge[] = [];
+  for (const edge of edges) {
+    const kind: EdgeKind = edge.dynamic ? 'dynamic' : edge.typeOnly ? 'type' : 'value';
+    if (!kinds.has(kind)) continue;
+    const id = importEdgeId(edge.file, edge.target);
+    if (seen.has(id)) continue;
+    seen.add(id);
+    graphEdges.push({ from: edge.file, to: edge.target, kind });
+  }
+  return importGraph(graphEdges, kinds, files);
+}
diff --git a/scripts/depgraph/model.ts b/scripts/depgraph/model.ts
index fe723a212a..63febf420b 100644
--- a/scripts/depgraph/model.ts
+++ b/scripts/depgraph/model.ts
@@ -17,8 +17,9 @@ import {
 import { ARCHITECTURE_OWNERSHIP, matchesDeclaredRoot } from '../layering/architecture-ownership.ts';
 import { genPostorder, getSuccessors, getTransitiveReduction } from '@statelyai/graph';
 import { importEdgeId, importGraph, VALUE_EDGES } from './import-graph.ts';
+import type { EdgeKind } from './import-graph.ts';
 
-export type EdgeKind = 'value' | 'type' | 'dynamic';
+export type { EdgeKind } from './import-graph.ts';
 
 export const AUTHORITY_LABELS = [
   'vocabulary',
diff --git a/scripts/fuzz/envelope.test.ts b/scripts/fuzz/envelope.test.ts
index 94cdcb02eb..7d737af9aa 100644
--- a/scripts/fuzz/envelope.test.ts
+++ b/scripts/fuzz/envelope.test.ts
@@ -9,7 +9,10 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import { fileURLToPath } from 'node:url';
+import { genBFS } from '@statelyai/graph';
 import { describe, expect, it } from 'vitest';
+import { parseImports } from '../layering/model.ts';
+import { importGraphFromResolvedEdges, STATIC_EDGES } from '../depgraph/import-graph.ts';
 import { CASE_GENERATION_INPUTS, NON_GENERATING_MODULES } from './envelope.ts';
 
 const FUZZ_DIR = path.dirname(fileURLToPath(import.meta.url));
@@ -17,26 +20,34 @@ const FUZZ_DIR = path.dirname(fileURLToPath(import.meta.url));
 /** Roots of case generation: the arbitraries, the seeds, the loop, and the violation rule. */
 const ROOTS = ['arbitraries.ts', 'generate.ts', 'targets.ts', 'invariant.ts'] as const;
 
-function localImportsOf(file: string): string[] {
-  const source = fs.readFileSync(path.join(FUZZ_DIR, file), 'utf8');
-  return [...source.matchAll(/from '\.\/([\w-]+\.ts)'/g)].map((match) => match[1]!);
+function generationGraph() {
+  const sources = new Map(
+    fs
+      .readdirSync(FUZZ_DIR)
+      .filter((file) => file.endsWith('.ts'))
+      .map((file) => [file, fs.readFileSync(path.join(FUZZ_DIR, file), 'utf8')]),
+  );
+  const edges = [];
+  for (const [file, source] of sources) {
+    if (file in NON_GENERATING_MODULES) continue;
+    for (const edge of parseImports(source)) {
+      if (!edge.spec.startsWith('./')) continue;
+      const target = path.posix.normalize(path.posix.join(path.posix.dirname(file), edge.spec));
+      if (!sources.has(target)) continue;
+      edges.push({ file, target, dynamic: edge.dynamic, typeOnly: edge.typeOnly });
+    }
+  }
+  return importGraphFromResolvedEdges(edges, STATIC_EDGES, sources.keys());
 }
 
+const graph = generationGraph();
+
 /**
  * Walk stops at a waived module: what a non-generating module imports cannot reach a case either
  * (the runner imports the target registry, which would otherwise drag the whole harness in).
  */
 function generationClosure(): Set<string> {
-  const seen = new Set<string>();
-  const queue = [...ROOTS];
-  while (queue.length > 0) {
-    const file = queue.pop()!;
-    if (seen.has(file)) continue;
-    seen.add(file);
-    if (file in NON_GENERATING_MODULES) continue;
-    queue.push(...localImportsOf(file));
-  }
-  return seen;
+  return new Set([...genBFS(graph, { from: ROOTS })].map(({ id }) => id));
 }
 
 describe('configHash coverage', () => {
diff --git a/scripts/layering/daemon-platform-runtime-inventory.ts b/scripts/layering/daemon-platform-runtime-inventory.ts
index 2704c2573b..67cc9e1be5 100644
--- a/scripts/layering/daemon-platform-runtime-inventory.ts
+++ b/scripts/layering/daemon-platform-runtime-inventory.ts
@@ -1,5 +1,7 @@
+import { genDFS } from '@statelyai/graph';
 import { isProductionSourceFile } from './tracked-sources.ts';
 import type { LayeringViolation, ResolvedImportEdge } from './model.ts';
+import { ALL_EDGES, importGraphFromResolvedEdges } from '../depgraph/import-graph.ts';
 
 // The classified inventory of every production daemon import that reaches the root platform-runtime
 // composition modules (#2278, ADR 0022, #2542). R65 already bans daemon imports of concrete platform
@@ -52,27 +54,19 @@ export function isRootPlatformRuntimeTarget(target: string): boolean {
 export function computePlatformMechanicsHubs(
   edges: readonly ResolvedImportEdge[],
 ): ReadonlySet<string> {
-  const importersByTarget = new Map<string, string[]>();
   const roots: string[] = [];
+  const rootSet = new Set<string>();
   for (const edge of edges) {
-    const importers = importersByTarget.get(edge.target);
-    if (importers === undefined) importersByTarget.set(edge.target, [edge.file]);
-    else importers.push(edge.file);
-    if (isRootPlatformRuntimeTarget(edge.target) && !roots.includes(edge.target)) {
+    if (isRootPlatformRuntimeTarget(edge.target) && !rootSet.has(edge.target)) {
+      rootSet.add(edge.target);
       roots.push(edge.target);
     }
   }
 
-  const hubs = new Set<string>(roots);
-  const seen = new Set<string>(roots);
-  const frontier = [...roots];
-  while (frontier.length > 0) {
-    for (const importer of importersByTarget.get(frontier.pop()!) ?? []) {
-      if (seen.has(importer)) continue;
-      seen.add(importer);
-      frontier.push(importer);
-      if (!importer.startsWith('src/daemon/')) hubs.add(importer);
-    }
+  const hubs = new Set<string>();
+  const graph = importGraphFromResolvedEdges(edges, ALL_EDGES, roots);
+  for (const { id: importer } of genDFS(graph, { from: roots, direction: 'incoming' })) {
+    if (!importer.startsWith('src/daemon/')) hubs.add(importer);
   }
   return hubs;
 }
diff --git a/scripts/layering/model.ts b/scripts/layering/model.ts
index 704c4afa7c..561cc60776 100644
--- a/scripts/layering/model.ts
+++ b/scripts/layering/model.ts
@@ -1,8 +1,14 @@
 import path from 'node:path';
 import { PLATFORMS } from '@agent-device/kernel/device';
+import { genCycles, getStronglyConnectedComponents } from '@statelyai/graph';
 import { parseSync } from 'oxc-parser';
 import { destructuredDynamicImportBindings, visitAst } from './layering-ast.ts';
 import { declaredRootModuleZone } from './root-module-zones.ts';
+import {
+  importGraphFromResolvedEdges,
+  STATIC_EDGES,
+  VALUE_EDGES,
+} from '../depgraph/import-graph.ts';
 
 export type ImportEdge = {
   spec: string;
@@ -397,91 +403,51 @@ export function resolveImportEdges(
 }
 
 export function findValueImportCycles(edges: readonly ResolvedImportEdge[]): string[][] {
-  const graph = new Map<string, Set<string>>();
-  for (const edge of edges) {
-    if (edge.dynamic || edge.typeOnly) continue;
-    const targets = graph.get(edge.file) ?? new Set<string>();
-    targets.add(edge.target);
-    graph.set(edge.file, targets);
-    if (!graph.has(edge.target)) graph.set(edge.target, new Set());
-  }
-
-  const indexByFile = new Map<string, number>();
-  const lowLinkByFile = new Map<string, number>();
-  const stack: string[] = [];
-  const onStack = new Set<string>();
-  const components: string[][] = [];
-  let nextIndex = 0;
-
-  function visit(file: string): void {
-    const index = nextIndex++;
-    indexByFile.set(file, index);
-    lowLinkByFile.set(file, index);
-    stack.push(file);
-    onStack.add(file);
-
-    for (const target of graph.get(file) ?? []) {
-      if (!indexByFile.has(target)) {
-        visit(target);
-        lowLinkByFile.set(file, Math.min(lowLinkByFile.get(file)!, lowLinkByFile.get(target)!));
-      } else if (onStack.has(target)) {
-        lowLinkByFile.set(file, Math.min(lowLinkByFile.get(file)!, indexByFile.get(target)!));
-      }
-    }
+  const graph = importGraphFromResolvedEdges(edges, VALUE_EDGES);
+  const componentByFile = new Map<string, number>();
+  const cyclicComponents = new Set<number>();
+  const membersByComponent = new Map<number, string[]>();
+  const components = getStronglyConnectedComponents(graph);
+  const selfCycleFiles = new Set(
+    graph.edges.filter((edge) => edge.sourceId === edge.targetId).map((edge) => edge.sourceId),
+  );
 
-    if (lowLinkByFile.get(file) !== indexByFile.get(file)) return;
-    const component: string[] = [];
-    let member: string;
-    do {
-      member = stack.pop()!;
-      onStack.delete(member);
-      component.push(member);
-    } while (member !== file);
-    const selfCycle = component.length === 1 && graph.get(file)?.has(file);
-    if (component.length > 1 || selfCycle) components.push(component);
+  for (const [index, component] of components.entries()) {
+    const memberIds = component.map(({ id }) => id);
+    if (memberIds.length < 2 && !selfCycleFiles.has(memberIds[0]!)) continue;
+    cyclicComponents.add(index);
+    membersByComponent.set(index, memberIds);
+    for (const id of memberIds) componentByFile.set(id, index);
   }
 
-  for (const file of graph.keys()) {
-    if (!indexByFile.has(file)) visit(file);
+  if (cyclicComponents.size === 0) return [];
+
+  const edgesByComponent = new Map<number, ResolvedImportEdge[]>();
+  for (const edge of edges) {
+    if (edge.dynamic || edge.typeOnly) continue;
+    const component = componentByFile.get(edge.file);
+    if (component === undefined || componentByFile.get(edge.target) !== component) continue;
+    const componentEdges = edgesByComponent.get(component) ?? [];
+    componentEdges.push(edge);
+    edgesByComponent.set(component, componentEdges);
   }
-  return components
-    .map((component) => findCyclePath(component, graph))
-    .sort((left, right) => left[0]!.localeCompare(right[0]!));
-}
 
-function findCyclePath(
-  component: readonly string[],
-  graph: ReadonlyMap<string, Set<string>>,
-): string[] {
-  const members = new Set(component);
-  const visited = new Set<string>();
-  const active = new Map<string, number>();
-  const stack: string[] = [];
-
-  function visit(file: string): string[] | null {
-    visited.add(file);
-    active.set(file, stack.length);
-    stack.push(file);
-    for (const target of graph.get(file) ?? []) {
-      if (!members.has(target)) continue;
-      const activeIndex = active.get(target);
-      if (activeIndex !== undefined) return [...stack.slice(activeIndex), target];
-      if (!visited.has(target)) {
-        const path = visit(target);
-        if (path) return path;
-      }
+  const cycles = [...cyclicComponents].map((component) => {
+    const componentGraph = importGraphFromResolvedEdges(
+      edgesByComponent.get(component) ?? [],
+      VALUE_EDGES,
+      membersByComponent.get(component),
+    );
+    const firstCycle = genCycles(componentGraph).next();
+    if (firstCycle.done) {
+      throw new Error(
+        `Expected a cycle inside strongly connected component: ${membersByComponent.get(component)!.join(', ')}`,
+      );
     }
-    stack.pop();
-    active.delete(file);
-    return null;
-  }
+    return [firstCycle.value.source.id, ...firstCycle.value.steps.map(({ node }) => node.id)];
+  });
 
-  for (const file of [...component].sort()) {
-    if (visited.has(file)) continue;
-    const path = visit(file);
-    if (path) return path;
-  }
-  throw new Error(`Expected a cycle inside strongly connected component: ${component.join(', ')}`);
+  return cycles.sort((left, right) => left[0]!.localeCompare(right[0]!));
 }
 
 function spineInversionPair(edge: ResolvedImportEdge): string | null {
@@ -566,48 +532,10 @@ export function largestTypeCycleSize(edges: readonly ResolvedImportEdge[]): numb
 
 /** Members of the largest value+type strongly-connected component, sorted. */
 export function largestTypeCycleMembers(edges: readonly ResolvedImportEdge[]): string[] {
-  const successors = new Map<string, string[]>();
-  for (const edge of edges) {
-    if (edge.dynamic) continue;
-    const list = successors.get(edge.file) ?? [];
-    list.push(edge.target);
-    successors.set(edge.file, list);
-  }
-
-  const index = new Map<string, number>();
-  const lowLink = new Map<string, number>();
-  const stack: string[] = [];
-  const onStack = new Set<string>();
-  let next = 0;
-  let biggest: string[] = [];
-
-  function visit(file: string): void {
-    index.set(file, next);
-    lowLink.set(file, next);
-    next++;
-    stack.push(file);
-    onStack.add(file);
-
-    for (const target of successors.get(file) ?? []) {
-      if (!index.has(target)) {
-        visit(target);
-        lowLink.set(file, Math.min(lowLink.get(file)!, lowLink.get(target)!));
-      } else if (onStack.has(target)) {
-        lowLink.set(file, Math.min(lowLink.get(file)!, index.get(target)!));
-      }
-    }
-
-    if (lowLink.get(file) !== index.get(file)) return;
-    const component: string[] = [];
-    let member: string;
-    do {
-      member = stack.pop()!;
-      onStack.delete(member);
-      component.push(member);
-    } while (member !== file);
-    if (component.length > biggest.length) biggest = component;
-  }
-
-  for (const file of successors.keys()) if (!index.has(file)) visit(file);
-  return biggest.sort();
+  return getStronglyConnectedComponents(importGraphFromResolvedEdges(edges, STATIC_EDGES))
+    .reduce<string[]>((largest, component) => {
+      if (component.length > largest.length) largest = component.map(({ id }) => id);
+      return largest;
+    }, [])
+    .sort();
 }
diff --git a/scripts/layering/provider-snapshot-presentation-policy.test.ts b/scripts/layering/provider-snapshot-presentation-policy.test.ts
index 1d0bb8a082..df0b5808e5 100644
--- a/scripts/layering/provider-snapshot-presentation-policy.test.ts
+++ b/scripts/layering/provider-snapshot-presentation-policy.test.ts
@@ -77,6 +77,41 @@ test('R73 rejects a provider import of the capture-kit presentation runtime subp
   );
 });
 
+test('R73 preserves breadth-first origin and finding order through a shared import graph', () => {
+  const provider = 'packages/provider-webdriver/src/provider.ts';
+  const first = 'src/graph-first.ts';
+  const second = 'src/graph-second.ts';
+  const join = 'src/graph-join.ts';
+  const firstPresentation = 'packages/capture-kit/src/snapshot/first.ts';
+  const secondPresentation = 'packages/capture-kit/src/snapshot/second.ts';
+  const joinedPresentation = 'packages/capture-kit/src/snapshot/joined.ts';
+  const sources = new Map([
+    [provider, "import '../../../src/graph-first.ts';\nimport '../../../src/graph-second.ts';\n"],
+    [first, "import '../packages/capture-kit/src/snapshot/first.ts';\nimport './graph-join.ts';\n"],
+    [second, "import '../packages/capture-kit/src/snapshot/second.ts';\n"],
+    [join, "import '../packages/capture-kit/src/snapshot/joined.ts';\n"],
+    [firstPresentation, 'export const first = true;\n'],
+    [secondPresentation, 'export const second = true;\n'],
+    [joinedPresentation, 'export const joined = true;\n'],
+  ]);
+  const result = providerSnapshotPresentationViolations(
+    sources,
+    resolveImportEdges(sources, workspaceSpecifierTargets(repoRoot)),
+  );
+
+  assert.deepEqual(
+    result.map(({ line, message }) => ({
+      line,
+      target: /reaches (.+?) before/.exec(message)?.[1],
+    })),
+    [
+      { line: 1, target: firstPresentation },
+      { line: 2, target: secondPresentation },
+      { line: 1, target: joinedPresentation },
+    ],
+  );
+});
+
 for (const planted of [
   {
     name: 'a planted provider residue discard',
diff --git a/scripts/layering/provider-snapshot-presentation-policy.ts b/scripts/layering/provider-snapshot-presentation-policy.ts
index 45a9902ea6..8dd9690792 100644
--- a/scripts/layering/provider-snapshot-presentation-policy.ts
+++ b/scripts/layering/provider-snapshot-presentation-policy.ts
@@ -11,9 +11,11 @@
 //   exports map cannot replace it: it restricts external specifiers, not the transitive walk
 //   into packages/capture-kit/src/snapshot/ or a provider-local `residue` property or assignment.
 
+import { genBFS } from '@statelyai/graph';
 import { parseSync } from 'oxc-parser';
 import type { LayeringViolation, ResolvedImportEdge } from './model.ts';
 import { memberPath, propertyName, visitAst } from './layering-ast.ts';
+import { ALL_EDGES, importGraphFromResolvedEdges } from '../depgraph/import-graph.ts';
 
 export const PROVIDER_SNAPSHOT_PRESENTATION_RULE = 'R73 provider-snapshot-presentation-ownership';
 export const IOS_SNAPSHOT_ACQUISITION_ENTRYPOINT =
@@ -52,11 +54,16 @@ function presentationImportViolations(
 ): LayeringViolation[] {
   const origins = new Map<string, ResolvedImportEdge>();
   const visited = new Set([providerFile]);
-  const queue = [providerFile];
   const violations: LayeringViolation[] = [];
+  const reachableEdges = [...edgesByFile.values()].flat();
+  const graph = importGraphFromResolvedEdges(
+    reachableEdges.filter((edge) => !isPresentationTarget(edge.file)),
+    ALL_EDGES,
+    [providerFile],
+  );
 
-  while (queue.length > 0) {
-    const file = queue.shift()!;
+  for (const { id: file } of genBFS(graph, providerFile)) {
+    if (isPresentationTarget(file)) continue;
     for (const edge of edgesByFile.get(file) ?? []) {
       const origin = origins.get(file) ?? edge;
       if (isPresentationTarget(edge.target)) {
@@ -72,7 +79,6 @@ function presentationImportViolations(
       if (visited.has(edge.target)) continue;
       visited.add(edge.target);
       origins.set(edge.target, origin);
-      queue.push(edge.target);
     }
   }
   return violations;
diff --git a/scripts/mutation/ownership.test.ts b/scripts/mutation/ownership.test.ts
index af966cbf90..9d3299eb3b 100644
--- a/scripts/mutation/ownership.test.ts
+++ b/scripts/mutation/ownership.test.ts
@@ -43,9 +43,15 @@ test('a kernel is owned by tests that reach it indirectly', () => {
   );
 });
 
+test('reachability includes its query root when the file is absent from the tracked graph', () => {
+  assert.deepEqual(
+    [...reachableFrom('src/untracked-fixture.ts', repoRoot)],
+    ['src/untracked-fixture.ts'],
+  );
+});
+
 test('ownership is complete: every test reaching a kernel owns it', () => {
   const owned = ownedTestFiles(repoRoot);
-  const cache = new Map<string, string[]>();
   for (const module of KERNEL_MODULES) {
     const sources = mutatedSources(module, repoRoot);
     assert.ok(sources.length > 0, `${module.id} mutates nothing`);
@@ -55,7 +61,7 @@ test('ownership is complete: every test reaching a kernel owns it', () => {
       `${module.id} has no owning tests — its score cannot be attributed`,
     );
     for (const testFile of files) {
-      const reachable = reachableFrom(testFile, repoRoot, cache);
+      const reachable = reachableFrom(testFile, repoRoot);
       assert.ok(
         sources.some((source) => reachable.has(source)),
         `${testFile} owns ${module.id} without reaching it`,
diff --git a/scripts/mutation/ownership.ts b/scripts/mutation/ownership.ts
index ecd3d7379b..b24db35b13 100644
--- a/scripts/mutation/ownership.ts
+++ b/scripts/mutation/ownership.ts
@@ -20,11 +20,15 @@
 
 import fs from 'node:fs';
 import path from 'node:path';
+import { genBFS, type Graph } from '@statelyai/graph';
 import {
   readWorkspacePackages,
   workspaceSpecifierTargets,
 } from '../layering/package-boundaries.ts';
+import { resolveImportEdges } from '../layering/model.ts';
+import { listTrackedTypeScriptFiles } from '../layering/tracked-sources.ts';
 import { walkFiles } from '../lib/walk-files.ts';
+import { ALL_EDGES, importGraphFromResolvedEdges } from '../depgraph/import-graph.ts';
 import {
   affectedModules,
   isKernelTestFile,
@@ -55,52 +59,32 @@ function exportTargetsFor(repoRoot: string): Map<string, string> {
   return cachedExportTargets.targets;
 }
 
-/**
- * Repository-relative modules a file imports: relative specifiers plus
- * workspace package specifiers resolved through their `exports` maps.
- */
-function importsOf(file: string, repoRoot: string, cache: Map<string, string[]>): string[] {
-  const cached = cache.get(file);
+const graphByRepository = new Map<string, Graph>();
+
+function ownershipGraph(repoRoot: string): Graph {
+  const cached = graphByRepository.get(repoRoot);
   if (cached) return cached;
-  const absolute = path.join(repoRoot, file);
-  const text = fs.existsSync(absolute) ? fs.readFileSync(absolute, 'utf8') : '';
-  const specifiers = [...text.matchAll(/(?:from|import)\s*\(?\s*'(?<spec>[.@][^']+)'/g)].map(
-    (match) => match.groups!.spec,
+  const files = listTrackedTypeScriptFiles(repoRoot);
+  const sources = new Map(
+    files.map((file) => [file, fs.readFileSync(path.join(repoRoot, file), 'utf8')]),
+  );
+  const graph = importGraphFromResolvedEdges(
+    resolveImportEdges(sources, exportTargetsFor(repoRoot)),
+    ALL_EDGES,
+    files,
   );
-  const exportTargets = exportTargetsFor(repoRoot);
-  const resolved = [
-    ...new Set(
-      specifiers.flatMap((specifier) => {
-        if (specifier.startsWith('@')) {
-          const target = exportTargets.get(specifier);
-          return target && fs.existsSync(path.join(repoRoot, target)) ? [target] : [];
-        }
-        const base = path.posix.normalize(path.posix.join(path.posix.dirname(file), specifier));
-        return [base, `${base}.ts`, `${base}/index.ts`].filter((candidate) =>
-          fs.existsSync(path.join(repoRoot, candidate)),
-        );
-      }),
-    ),
-  ].filter((candidate) => candidate.endsWith('.ts'));
-  cache.set(file, resolved);
-  return resolved;
+  graphByRepository.set(repoRoot, graph);
+  return graph;
+}
+
+function reachableInGraph(file: string, graph: Graph): Set<string> {
+  const root = normalizePath(file);
+  return new Set([root, ...[...genBFS(graph, root)].map(({ id }) => id)]);
 }
 
 /** Every repository-relative module `file` reaches through the import graph. */
-export function reachableFrom(
-  file: string,
-  repoRoot: string,
-  cache: Map<string, string[]> = new Map(),
-): Set<string> {
-  const seen = new Set<string>();
-  const queue = [normalizePath(file)];
-  while (queue.length > 0) {
-    const current = queue.shift()!;
-    if (seen.has(current)) continue;
-    seen.add(current);
-    queue.push(...importsOf(current, repoRoot, cache));
-  }
-  return seen;
+export function reachableFrom(file: string, repoRoot: string): Set<string> {
+  return reachableInGraph(file, ownershipGraph(repoRoot));
 }
 
 /** The concrete sources Stryker mutates for a module. */
@@ -115,14 +99,14 @@ type Deriver = {
 
 /** A deriver with caches shared across files — one graph walk per module, not per query. */
 export function ownershipDeriver(repoRoot: string): Deriver {
-  const importCache = new Map<string, string[]>();
+  const graph = ownershipGraph(repoRoot);
   const sources = KERNEL_MODULES.map((module) => ({
     id: module.id,
     sources: new Set(mutatedSources(module, repoRoot)),
   }));
   return {
     ownersOf(testFile) {
-      const reachable = reachableFrom(testFile, repoRoot, importCache);
+      const reachable = reachableInGraph(testFile, graph);
       return sources
         .filter((entry) => [...entry.sources].some((source) => reachable.has(source)))
         .map((entry) => entry.id);

From 721cf76721cf0265232da52daf81f39478da8a39 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Pierzcha=C5=82a?= <thymikee@gmail.com>
Date: Thu, 8 Oct 2026 10:54:46 +0200
Subject: [PATCH 2/6] refactor(graph): address traversal review findings

---
 scripts/depgraph/import-graph.ts                  |  8 +++++++-
 scripts/depgraph/model.ts                         |  8 +-------
 .../provider-snapshot-presentation-policy.test.ts |  5 ++++-
 .../provider-snapshot-presentation-policy.ts      | 15 ++++++++-------
 4 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/scripts/depgraph/import-graph.ts b/scripts/depgraph/import-graph.ts
index 25a731b5ee..e17a9ea826 100644
--- a/scripts/depgraph/import-graph.ts
+++ b/scripts/depgraph/import-graph.ts
@@ -35,6 +35,12 @@ type ResolvedGraphEdge = {
   typeOnly: boolean;
 };
 
+export function edgeKind(edge: Pick<ResolvedGraphEdge, 'dynamic' | 'typeOnly'>): EdgeKind {
+  if (edge.dynamic) return 'dynamic';
+  if (edge.typeOnly) return 'type';
+  return 'value';
+}
+
 /**
  * Identity of one file pair, shared by `collapseEdges` and the graph's edge ids. NUL cannot occur
  * in a file path, so distinct pairs never share an id.
@@ -77,7 +83,7 @@ export function importGraphFromResolvedEdges(
   const seen = new Set<string>();
   const graphEdges: ImportGraphEdge[] = [];
   for (const edge of edges) {
-    const kind: EdgeKind = edge.dynamic ? 'dynamic' : edge.typeOnly ? 'type' : 'value';
+    const kind = edgeKind(edge);
     if (!kinds.has(kind)) continue;
     const id = importEdgeId(edge.file, edge.target);
     if (seen.has(id)) continue;
diff --git a/scripts/depgraph/model.ts b/scripts/depgraph/model.ts
index 63febf420b..4ce460e4ba 100644
--- a/scripts/depgraph/model.ts
+++ b/scripts/depgraph/model.ts
@@ -16,7 +16,7 @@ import {
 } from '../layering/model.ts';
 import { ARCHITECTURE_OWNERSHIP, matchesDeclaredRoot } from '../layering/architecture-ownership.ts';
 import { genPostorder, getSuccessors, getTransitiveReduction } from '@statelyai/graph';
-import { importEdgeId, importGraph, VALUE_EDGES } from './import-graph.ts';
+import { edgeKind, importEdgeId, importGraph, VALUE_EDGES } from './import-graph.ts';
 import type { EdgeKind } from './import-graph.ts';
 
 export type { EdgeKind } from './import-graph.ts';
@@ -165,12 +165,6 @@ function countLines(source: string): number {
   return lines;
 }
 
-function edgeKind(edge: ResolvedImportEdge): EdgeKind {
-  if (edge.dynamic) return 'dynamic';
-  if (edge.typeOnly) return 'type';
-  return 'value';
-}
-
 /**
  * Deduplicate parsed import edges down to one edge per (from, to) pair, keeping the
  * strongest kind. A file that imports both a type and a value from the same module has one
diff --git a/scripts/layering/provider-snapshot-presentation-policy.test.ts b/scripts/layering/provider-snapshot-presentation-policy.test.ts
index df0b5808e5..9f226590ab 100644
--- a/scripts/layering/provider-snapshot-presentation-policy.test.ts
+++ b/scripts/layering/provider-snapshot-presentation-policy.test.ts
@@ -88,7 +88,10 @@ test('R73 preserves breadth-first origin and finding order through a shared impo
   const sources = new Map([
     [provider, "import '../../../src/graph-first.ts';\nimport '../../../src/graph-second.ts';\n"],
     [first, "import '../packages/capture-kit/src/snapshot/first.ts';\nimport './graph-join.ts';\n"],
-    [second, "import '../packages/capture-kit/src/snapshot/second.ts';\n"],
+    [
+      second,
+      "import '../packages/capture-kit/src/snapshot/second.ts';\nimport './graph-join.ts';\n",
+    ],
     [join, "import '../packages/capture-kit/src/snapshot/joined.ts';\n"],
     [firstPresentation, 'export const first = true;\n'],
     [secondPresentation, 'export const second = true;\n'],
diff --git a/scripts/layering/provider-snapshot-presentation-policy.ts b/scripts/layering/provider-snapshot-presentation-policy.ts
index 8dd9690792..c104a349d3 100644
--- a/scripts/layering/provider-snapshot-presentation-policy.ts
+++ b/scripts/layering/provider-snapshot-presentation-policy.ts
@@ -40,9 +40,15 @@ export function providerSnapshotPresentationViolations(
   }
 
   const violations: LayeringViolation[] = [];
+  const reachableEdges = [...edgesByFile.values()].flat();
+  const graph = importGraphFromResolvedEdges(
+    reachableEdges.filter((edge) => !isPresentationTarget(edge.file)),
+    ALL_EDGES,
+    sources.keys(),
+  );
   for (const file of sources.keys()) {
     if (!PROVIDER_SOURCE.test(file)) continue;
-    violations.push(...presentationImportViolations(file, edgesByFile));
+    violations.push(...presentationImportViolations(file, edgesByFile, graph));
     violations.push(...residueViolations(file, sources.get(file)!));
   }
   return violations;
@@ -51,16 +57,11 @@ export function providerSnapshotPresentationViolations(
 function presentationImportViolations(
   providerFile: string,
   edgesByFile: ReadonlyMap<string, readonly ResolvedImportEdge[]>,
+  graph: ReturnType<typeof importGraphFromResolvedEdges>,
 ): LayeringViolation[] {
   const origins = new Map<string, ResolvedImportEdge>();
   const visited = new Set([providerFile]);
   const violations: LayeringViolation[] = [];
-  const reachableEdges = [...edgesByFile.values()].flat();
-  const graph = importGraphFromResolvedEdges(
-    reachableEdges.filter((edge) => !isPresentationTarget(edge.file)),
-    ALL_EDGES,
-    [providerFile],
-  );
 
   for (const { id: file } of genBFS(graph, providerFile)) {
     if (isPresentationTarget(file)) continue;

From ffafd8ab0260c41f332bfc38783df5b5b78d0bac Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Pierzcha=C5=82a?= <thymikee@gmail.com>
Date: Thu, 8 Oct 2026 12:44:38 +0200
Subject: [PATCH 3/6] fix(mutation): keep tooling canary within budget

---
 scripts/mutation/modules.ts | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/scripts/mutation/modules.ts b/scripts/mutation/modules.ts
index beed008978..d0a6f24939 100644
--- a/scripts/mutation/modules.ts
+++ b/scripts/mutation/modules.ts
@@ -118,12 +118,11 @@ export function mutateGlobs(ids: readonly ModuleId[] = ALL_MODULE_IDS): string[]
 }
 
 /**
- * The module a lane-tooling change proves itself against. `kernel-errors` is the
- * cheapest real sweep in the registry (one file, ~183 mutants), so a change to
- * the harness or the config runs actual mutants end to end without paying for
- * the full sweep.
+ * The module a lane-tooling change proves itself against. Keep this to a real
+ * end-to-end sweep whose observed related-test scope fits the 30-minute job
+ * budget; mutant count alone does not capture replay cost.
  */
-export const LANE_CANARY: ModuleId = 'kernel-errors';
+export const LANE_CANARY: ModuleId = 'snapshot-occlusion';
 
 /** One mutation job: a module, optionally one slice of it. */
 export type ShardSpec = { name: string; module: ModuleId; shard?: string };

From 9d3eba862347772d653510f5b475edbc9592a121 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Pierzcha=C5=82a?= <thymikee@gmail.com>
Date: Thu, 8 Oct 2026 12:48:13 +0200
Subject: [PATCH 4/6] docs(mutation): describe budget-calibrated canary

---
 .github/workflows/mutation-affected.yml | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/mutation-affected.yml b/.github/workflows/mutation-affected.yml
index 7c0aef5391..2307c2f2cc 100644
--- a/.github/workflows/mutation-affected.yml
+++ b/.github/workflows/mutation-affected.yml
@@ -12,12 +12,12 @@ name: Mutation Affected
 # ownership instead would run the full ten-shard sweep on 24 of the last 40
 # merged PRs.
 #
-# On a harness diff the matrix is the canary (`LANE_CANARY`, the registry's
-# cheapest real sweep — lane sources own no kernel, so derivation alone would
-# select nothing) plus any kernel that same diff reaches through the import
-# graph (scripts/mutation/ownership.ts): a kernel source, or a test that reaches
-# one. Selected modules are sharded like the weekly sweep, so the PR's wall
-# clock is one module rather than their sum.
+# On a harness diff the matrix is the canary (`LANE_CANARY`, selected by
+# observed end-to-end runtime within the job budget — lane sources own no kernel,
+# so derivation alone would select nothing) plus any kernel that same diff
+# reaches through the import graph (scripts/mutation/ownership.ts): a kernel
+# source, or a test that reaches one. Selected modules are sharded like the
+# weekly sweep, so the PR's wall clock is one module rather than their sum.
 
 on:
   pull_request:

From 98b6e832c42edfa9a9a2c31efacf8bca0c3a1d82 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Pierzcha=C5=82a?= <thymikee@gmail.com>
Date: Thu, 8 Oct 2026 15:35:09 +0200
Subject: [PATCH 5/6] fix(graph): preserve cycle representatives with shared
 traversal

---
 scripts/depgraph/model.test.ts | 26 ++++++++++++++++
 scripts/depgraph/model.ts      |  2 --
 scripts/layering/model.ts      | 55 +++++++++++-----------------------
 scripts/mutation/ownership.ts  |  2 +-
 4 files changed, 45 insertions(+), 40 deletions(-)

diff --git a/scripts/depgraph/model.test.ts b/scripts/depgraph/model.test.ts
index 46c99b501f..4a1b3f86ba 100644
--- a/scripts/depgraph/model.test.ts
+++ b/scripts/depgraph/model.test.ts
@@ -372,6 +372,32 @@ test('collectCycles separates gate-rejected value cycles from type-only and dyna
   );
 });
 
+test('collectCycles keeps the representative and edge kinds for a chorded three-file SCC', () => {
+  const edges = resolveImportEdges(
+    sources({
+      'src/core/a.ts': "import './b.ts';\nimport './c.ts';",
+      'src/core/b.ts': "import './c.ts';",
+      'src/core/c.ts': "import './a.ts';\nimport type { B } from './b.ts';\nvoid import('./b.ts');",
+    }),
+  );
+  assert.deepEqual(collectCycles(edges), [
+    { kind: 'value', path: ['src/core/a.ts', 'src/core/b.ts', 'src/core/c.ts', 'src/core/a.ts'] },
+  ]);
+});
+
+test('collectCycles preserves the first DFS back edge when a chord closes below the SCC root', () => {
+  const edges = resolveImportEdges(
+    sources({
+      'src/core/a.ts': "import './b.ts';",
+      'src/core/b.ts': "import './c.ts';",
+      'src/core/c.ts': "import './b.ts';\nimport './a.ts';",
+    }),
+  );
+  assert.deepEqual(collectCycles(edges), [
+    { kind: 'value', path: ['src/core/b.ts', 'src/core/c.ts', 'src/core/b.ts'] },
+  ]);
+});
+
 test('buildGraph reports zone membership, degrees, and cross-zone edge counts', () => {
   const files = sources({
     'packages/kernel/src/errors.ts': 'export const fail = 1;\n',
diff --git a/scripts/depgraph/model.ts b/scripts/depgraph/model.ts
index 4ce460e4ba..3743ed370d 100644
--- a/scripts/depgraph/model.ts
+++ b/scripts/depgraph/model.ts
@@ -19,8 +19,6 @@ import { genPostorder, getSuccessors, getTransitiveReduction } from '@statelyai/
 import { edgeKind, importEdgeId, importGraph, VALUE_EDGES } from './import-graph.ts';
 import type { EdgeKind } from './import-graph.ts';
 
-export type { EdgeKind } from './import-graph.ts';
-
 export const AUTHORITY_LABELS = [
   'vocabulary',
   'capability',
diff --git a/scripts/layering/model.ts b/scripts/layering/model.ts
index 561cc60776..4f44ee1346 100644
--- a/scripts/layering/model.ts
+++ b/scripts/layering/model.ts
@@ -1,6 +1,6 @@
 import path from 'node:path';
 import { PLATFORMS } from '@agent-device/kernel/device';
-import { genCycles, getStronglyConnectedComponents } from '@statelyai/graph';
+import { createGraph, genDFS, getStronglyConnectedComponents, getSubgraph } from '@statelyai/graph';
 import { parseSync } from 'oxc-parser';
 import { destructuredDynamicImportBindings, visitAst } from './layering-ast.ts';
 import { declaredRootModuleZone } from './root-module-zones.ts';
@@ -404,47 +404,28 @@ export function resolveImportEdges(
 
 export function findValueImportCycles(edges: readonly ResolvedImportEdge[]): string[][] {
   const graph = importGraphFromResolvedEdges(edges, VALUE_EDGES);
-  const componentByFile = new Map<string, number>();
-  const cyclicComponents = new Set<number>();
-  const membersByComponent = new Map<number, string[]>();
-  const components = getStronglyConnectedComponents(graph);
   const selfCycleFiles = new Set(
     graph.edges.filter((edge) => edge.sourceId === edge.targetId).map((edge) => edge.sourceId),
   );
-
-  for (const [index, component] of components.entries()) {
+  const components = getStronglyConnectedComponents(graph).filter(
+    (component) => component.length > 1 || selfCycleFiles.has(component[0]!.id),
+  );
+  const cycles = components.map((component) => {
     const memberIds = component.map(({ id }) => id);
-    if (memberIds.length < 2 && !selfCycleFiles.has(memberIds[0]!)) continue;
-    cyclicComponents.add(index);
-    membersByComponent.set(index, memberIds);
-    for (const id of memberIds) componentByFile.set(id, index);
-  }
-
-  if (cyclicComponents.size === 0) return [];
-
-  const edgesByComponent = new Map<number, ResolvedImportEdge[]>();
-  for (const edge of edges) {
-    if (edge.dynamic || edge.typeOnly) continue;
-    const component = componentByFile.get(edge.file);
-    if (component === undefined || componentByFile.get(edge.target) !== component) continue;
-    const componentEdges = edgesByComponent.get(component) ?? [];
-    componentEdges.push(edge);
-    edgesByComponent.set(component, componentEdges);
-  }
-
-  const cycles = [...cyclicComponents].map((component) => {
-    const componentGraph = importGraphFromResolvedEdges(
-      edgesByComponent.get(component) ?? [],
-      VALUE_EDGES,
-      membersByComponent.get(component),
-    );
-    const firstCycle = genCycles(componentGraph).next();
-    if (firstCycle.done) {
-      throw new Error(
-        `Expected a cycle inside strongly connected component: ${membersByComponent.get(component)!.join(', ')}`,
-      );
+    const componentGraph = getSubgraph(graph, memberIds);
+    const firstEdgeByFile = new Map<string, (typeof graph.edges)[number]>();
+    for (const edge of componentGraph.edges) {
+      if (!firstEdgeByFile.has(edge.sourceId)) firstEdgeByFile.set(edge.sourceId, edge);
     }
-    return [firstCycle.value.source.id, ...firstCycle.value.steps.map(({ node }) => node.id)];
+    // Inside an SCC every file has an outgoing edge. DFS finds its first back edge before
+    // backtracking, so following only the first outgoing edge preserves the reported cycle.
+    const firstEdgeGraph = createGraph({
+      nodes: componentGraph.nodes,
+      edges: [...firstEdgeByFile.values()],
+    });
+    const path = [...genDFS(firstEdgeGraph, [...memberIds].sort()[0]!)].map(({ id }) => id);
+    const target = firstEdgeByFile.get(path.at(-1)!)!.targetId;
+    return [...path.slice(path.indexOf(target)), target];
   });
 
   return cycles.sort((left, right) => left[0]!.localeCompare(right[0]!));
diff --git a/scripts/mutation/ownership.ts b/scripts/mutation/ownership.ts
index b24db35b13..e61e54eeca 100644
--- a/scripts/mutation/ownership.ts
+++ b/scripts/mutation/ownership.ts
@@ -97,7 +97,7 @@ type Deriver = {
   ownersOf: (testFile: string) => ModuleId[];
 };
 
-/** A deriver with caches shared across files — one graph walk per module, not per query. */
+/** Shares the tracked-source graph and mutated-source sets across test queries. */
 export function ownershipDeriver(repoRoot: string): Deriver {
   const graph = ownershipGraph(repoRoot);
   const sources = KERNEL_MODULES.map((module) => ({

From 8ed2225f0811ad2932c34daf08942dfa20907a17 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Pierzcha=C5=82a?= <thymikee@gmail.com>
Date: Thu, 8 Oct 2026 15:47:23 +0200
Subject: [PATCH 6/6] test(depgraph): focus chord fixture on value-cycle
 selection

---
 scripts/depgraph/model.test.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/depgraph/model.test.ts b/scripts/depgraph/model.test.ts
index 4a1b3f86ba..a9ca7deac4 100644
--- a/scripts/depgraph/model.test.ts
+++ b/scripts/depgraph/model.test.ts
@@ -372,12 +372,12 @@ test('collectCycles separates gate-rejected value cycles from type-only and dyna
   );
 });
 
-test('collectCycles keeps the representative and edge kinds for a chorded three-file SCC', () => {
+test('collectCycles keeps the value-cycle representative for a chorded three-file SCC', () => {
   const edges = resolveImportEdges(
     sources({
       'src/core/a.ts': "import './b.ts';\nimport './c.ts';",
       'src/core/b.ts': "import './c.ts';",
-      'src/core/c.ts': "import './a.ts';\nimport type { B } from './b.ts';\nvoid import('./b.ts');",
+      'src/core/c.ts': "import './a.ts';",
     }),
   );
   assert.deepEqual(collectCycles(edges), [