From ac93025fd112fdd70c376b3ad05f8d95c2154d68 Mon Sep 17 00:00:00 2001
From: Ramachandra Avuthu <ravuthu@adobe.com>
Date: Wed, 15 Jul 2026 15:51:14 -0400
Subject: [PATCH 1/2] localize the inherited content

---
 nx/blocks/loc/utils/msm.js               | 63 ++++++++++++++++++++++++
 nx/blocks/loc/views/translate/index.js   |  6 +--
 nx/blocks/loc/views/validate/validate.js | 14 ++++--
 test/utils/tree.test.js                  |  8 ++-
 4 files changed, 81 insertions(+), 10 deletions(-)
 create mode 100644 nx/blocks/loc/utils/msm.js

diff --git a/nx/blocks/loc/utils/msm.js b/nx/blocks/loc/utils/msm.js
new file mode 100644
index 000000000..6252fc38d
--- /dev/null
+++ b/nx/blocks/loc/utils/msm.js
@@ -0,0 +1,63 @@
+import { DA_ADMIN } from '../../../../nx2/utils/utils.js';
+import { daFetch } from '../../../../nx2/utils/api.js';
+
+const sourceOf = (row) => row.base || row.source;
+const linkedOf = (row) => row.satellite || row.linked;
+
+const msmRowsCache = {};
+
+export function fetchMsmRows(org) {
+  msmRowsCache[org] ??= (async () => {
+    try {
+      const resp = await daFetch({ url: `${DA_ADMIN}/config/${org}/` });
+      if (resp.status === 404) return [];
+      if (!resp.ok) throw new Error(`config ${resp.status}`);
+      const json = await resp.json();
+      return json?.msm?.data || [];
+    } catch {
+      delete msmRowsCache[org];
+      return [];
+    }
+  })();
+  return msmRowsCache[org];
+}
+
+export function getSourceChain(rows, site) {
+  const chain = [];
+  const visited = new Set();
+  let current = site;
+  while (current && !visited.has(current)) {
+    visited.add(current);
+    const linkedSite = current;
+    const parentRow = rows.find((row) => linkedOf(row) === linkedSite);
+    const parent = parentRow && sourceOf(parentRow);
+    if (!parent) break;
+    chain.push(parent);
+    current = parent;
+  }
+  return chain;
+}
+
+export async function fetchWithMsmFallback({ org, site, daPath, opts }) {
+  const fetchFrom = (fromSite) => daFetch({
+    url: `${DA_ADMIN}/source/${org}/${fromSite}${daPath}`,
+    opts,
+  });
+
+  const selfResp = await fetchFrom(site);
+  if (selfResp.ok) return { resp: selfResp, resolvedSite: site, inherited: false };
+
+  if (selfResp.status !== 404) return { resp: selfResp, resolvedSite: site, inherited: false };
+
+  const rows = await fetchMsmRows(org);
+  if (!rows.length) return { resp: selfResp, resolvedSite: site, inherited: false };
+
+  const chain = getSourceChain(rows, site);
+  for (const ancestor of chain) {
+    // eslint-disable-next-line no-await-in-loop
+    const resp = await fetchFrom(ancestor);
+    if (resp.ok) return { resp, resolvedSite: ancestor, inherited: true };
+  }
+
+  return { resp: selfResp, resolvedSite: site, inherited: false };
+}
diff --git a/nx/blocks/loc/views/translate/index.js b/nx/blocks/loc/views/translate/index.js
index 3d44665ef..562bb2c45 100644
--- a/nx/blocks/loc/views/translate/index.js
+++ b/nx/blocks/loc/views/translate/index.js
@@ -1,8 +1,7 @@
-import { DA_ADMIN } from '../../../../../nx2/utils/utils.js';
 import { Queue } from '../../../../../nx2/public/utils/tree.js';
-import { daFetch } from '../../../../../nx2/utils/api.js';
 
 import { convertPath, createSnapshotPrefix, fetchConfig } from '../../utils/utils.js';
+import { fetchWithMsmFallback } from '../../utils/msm.js';
 import { MAX_CONCURRENT_READS, MAX_CONCURRENT_WRITES, mergeCopy, overwriteCopy } from '../../project/index.js';
 
 let CONNECTOR;
@@ -50,7 +49,8 @@ export async function getUrls(
     // Fetch the content and add DNT
     const fetchUrl = async (url) => {
       const opts = { headers: { 'Cache-Control': 'no-cache' } };
-      const resp = await daFetch({ url: `${DA_ADMIN}/source/${org}/${site}${url.daDestPath}`, opts });
+      // Resolve MSM inheritance so inherited pages translate from their source site.
+      const { resp } = await fetchWithMsmFallback({ org, site, daPath: url.daDestPath, opts });
       if (!resp.ok) {
         url.error = `Error fetching content from ${url.daDestPath} - ${resp.status}`;
         return;
diff --git a/nx/blocks/loc/views/validate/validate.js b/nx/blocks/loc/views/validate/validate.js
index a6f7754d5..0ed51c9c8 100644
--- a/nx/blocks/loc/views/validate/validate.js
+++ b/nx/blocks/loc/views/validate/validate.js
@@ -1,10 +1,9 @@
 import { LitElement, html, nothing } from 'da-lit';
-import { DA_ADMIN } from '../../../../../nx2/utils/utils.js';
 import { loadStyle } from '../../../../../nx2/scripts/nx.js';
-import { daFetch } from '../../../../../nx2/utils/api.js';
 import { Queue } from '../../../../../nx2/public/utils/tree.js';
 
 import { convertPath, createSnapshotPrefix, fetchConfig } from '../../utils/utils.js';
+import { fetchWithMsmFallback } from '../../utils/msm.js';
 import { getFragmentUrls } from './validate-utils.js';
 import { MAX_CONCURRENT_READS } from '../../project/index.js';
 
@@ -101,16 +100,21 @@ class NxLocValidate extends LitElement {
     const isSheet = pathname.endsWith('.json');
     const extPath = isSheet ? pathname : `${pathname}.html`;
     const snapshotUrlFragment = createSnapshotPrefix(this._snapshot);
-    const daUrl = `${DA_ADMIN}/source/${this._org}/${this._site}${snapshotUrlFragment}${extPath}`;
-    const resp = await daFetch({ url: daUrl });
+    const daPath = `${snapshotUrlFragment}${extPath}`;
+    const { resp, resolvedSite, inherited } = await fetchWithMsmFallback({
+      org: this._org,
+      site: this._site,
+      daPath,
+    });
     const text = await resp.text();
     const ok = resp.status === 200;
     url.status = ok ? 'ready' : 'error - not found';
     url.checked = ok;
+    url.inherited = ok && inherited;
     url.sheet = isSheet;
     url.extPath = extPath;
     url.fragment = url.pathname.includes('/fragments/');
-    url.daEdit = `${DA_LIVE}/edit#/${this._org}/${this._site}${snapshotUrlFragment}${url.pathname}`;
+    url.daEdit = `${DA_LIVE}/edit#/${this._org}/${resolvedSite}${snapshotUrlFragment}${url.pathname}`;
     if (ok) await this.findFragments(text);
     this.requestUpdate();
   }
diff --git a/test/utils/tree.test.js b/test/utils/tree.test.js
index 071fcd063..529f2dac7 100644
--- a/test/utils/tree.test.js
+++ b/test/utils/tree.test.js
@@ -196,7 +196,9 @@ describe('Queue', () => {
     await queue.push('item2');
 
     const timeDiff = timestamps[1] - timestamps[0];
-    expect(timeDiff).to.be.at.least(100);
+    // Allow a small tolerance: browsers coarsen Date.now() (timer precision
+    // mitigations), so a real 100ms delay can read back a few ms short.
+    expect(timeDiff).to.be.at.least(95);
   });
 
   it('Processes items in FIFO order', async () => {
@@ -575,7 +577,9 @@ describe('crawl', () => {
     await results;
 
     const timeDiff = secondFetchTime - firstFetchTime;
-    expect(timeDiff).to.be.at.least(50);
+    // Allow a small tolerance: browsers coarsen Date.now() (timer precision
+    // mitigations), so a real 50ms delay can read back a few ms short.
+    expect(timeDiff).to.be.at.least(45);
   });
 
   it('Resolves results promise with all files', async () => {

From 5bbc76b7ba914668370b411eb1dd86ff2db1abe5 Mon Sep 17 00:00:00 2001
From: Ramachandra Avuthu <ravuthu@adobe.com>
Date: Thu, 16 Jul 2026 15:39:33 -0400
Subject: [PATCH 2/2] msm unit tests

---
 test/loc/msm.test.js | 202 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 202 insertions(+)
 create mode 100644 test/loc/msm.test.js

diff --git a/test/loc/msm.test.js b/test/loc/msm.test.js
new file mode 100644
index 000000000..1b17fcd28
--- /dev/null
+++ b/test/loc/msm.test.js
@@ -0,0 +1,202 @@
+import { expect } from '@esm-bundle/chai';
+import sinon from 'sinon';
+import { DA_ADMIN } from '../../nx2/utils/utils.js';
+import { fetchMsmRows, getSourceChain, fetchWithMsmFallback } from '../../nx/blocks/loc/utils/msm.js';
+
+const DA_PATH = '/en/about.html';
+
+function makeResp(status, body = '') {
+  return {
+    ok: status >= 200 && status < 300,
+    status,
+    headers: new Headers(),
+    json: async () => body,
+    text: async () => (typeof body === 'string' ? body : JSON.stringify(body)),
+  };
+}
+
+function stubFetch({ org, config, sources = {} }) {
+  globalThis.fetch = sinon.stub().callsFake((url) => {
+    if (url.includes('/config/')) {
+      if (typeof config === 'number') return Promise.resolve(makeResp(config));
+      return Promise.resolve(makeResp(200, { msm: { data: config || [] } }));
+    }
+    const site = Object.keys(sources).find((s) => url.includes(`/source/${org}/${s}/`));
+    const status = site ? sources[site] : 404;
+    return Promise.resolve(makeResp(status, status === 200 ? '<main>content</main>' : ''));
+  });
+}
+
+const configCalls = () => globalThis.fetch.args.filter(([url]) => url.includes('/config/'));
+
+describe('msm', () => {
+  let originalFetch;
+
+  beforeEach(() => {
+    originalFetch = globalThis.fetch;
+  });
+
+  afterEach(() => {
+    globalThis.fetch = originalFetch;
+    sinon.restore();
+  });
+
+  describe('getSourceChain', () => {
+    it('returns an empty chain when the linked site has no source', () => {
+      const rows = [{ source: 'source-site', linked: 'linked-site' }];
+      expect(getSourceChain(rows, 'unrelated-site')).to.deep.equal([]);
+    });
+
+    it('resolves the source of a linked site', () => {
+      const rows = [{ source: 'source-site', linked: 'linked-site' }];
+      expect(getSourceChain(rows, 'linked-site')).to.deep.equal(['source-site']);
+    });
+
+    it('walks a multi-level chain nearest-source-first', () => {
+      const rows = [
+        { source: 'source-site', linked: 'mid-site' },
+        { source: 'mid-site', linked: 'linked-site' },
+      ];
+      expect(getSourceChain(rows, 'linked-site')).to.deep.equal(['mid-site', 'source-site']);
+    });
+
+    it('guards against cycles without looping forever', () => {
+      const rows = [
+        { source: 'site-a', linked: 'site-b' },
+        { source: 'site-b', linked: 'site-a' },
+      ];
+      expect(getSourceChain(rows, 'site-a')).to.deep.equal(['site-b', 'site-a']);
+    });
+
+    it('supports the legacy base/satellite column names', () => {
+      const rows = [{ base: 'source-site', satellite: 'linked-site' }];
+      expect(getSourceChain(rows, 'linked-site')).to.deep.equal(['source-site']);
+    });
+
+    it('falls back to the alternate column when a cell is blank', () => {
+      const rows = [{ base: '', source: 'source-site', satellite: '', linked: 'linked-site' }];
+      expect(getSourceChain(rows, 'linked-site')).to.deep.equal(['source-site']);
+    });
+  });
+
+  describe('fetchMsmRows', () => {
+    it('returns the msm sheet rows on a successful config fetch', async () => {
+      const rows = [{ source: 'source-site', linked: 'linked-site' }];
+      stubFetch({ org: 'rows-ok', config: rows });
+      expect(await fetchMsmRows('rows-ok')).to.deep.equal(rows);
+    });
+
+    it('returns [] when the config has no msm sheet', async () => {
+      globalThis.fetch = sinon.stub().resolves(makeResp(200, { other: { data: [] } }));
+      expect(await fetchMsmRows('rows-nomsm')).to.deep.equal([]);
+    });
+
+    it('memoizes a successful lookup (one config fetch for repeat calls)', async () => {
+      stubFetch({ org: 'rows-memo', config: [{ source: 'source-site', linked: 'linked-site' }] });
+      await fetchMsmRows('rows-memo');
+      await fetchMsmRows('rows-memo');
+      expect(configCalls().length).to.equal(1);
+    });
+
+    it('caches an absent config (404) so non-MSM orgs are not re-probed', async () => {
+      stubFetch({ org: 'rows-404', config: 404 });
+      expect(await fetchMsmRows('rows-404')).to.deep.equal([]);
+      await fetchMsmRows('rows-404');
+      expect(configCalls().length).to.equal(1);
+    });
+
+    it('does not cache a transient failure (500) so a later call retries', async () => {
+      stubFetch({ org: 'rows-500', config: 500 });
+      expect(await fetchMsmRows('rows-500')).to.deep.equal([]);
+      await fetchMsmRows('rows-500');
+      expect(configCalls().length).to.equal(2);
+    });
+  });
+
+  describe('fetchWithMsmFallback', () => {
+    it('returns the linked-site response without consulting MSM when the file exists', async () => {
+      stubFetch({ org: 'self-ok', sources: { 'linked-site': 200 } });
+      const result = await fetchWithMsmFallback({ org: 'self-ok', site: 'linked-site', daPath: DA_PATH });
+      expect(result.resp.ok).to.equal(true);
+      expect(result.resolvedSite).to.equal('linked-site');
+      expect(result.inherited).to.equal(false);
+      expect(configCalls().length).to.equal(0);
+    });
+
+    it('resolves an inherited page from its source site', async () => {
+      stubFetch({
+        org: 'inherit',
+        config: [{ source: 'source-site', linked: 'linked-site' }],
+        sources: { 'source-site': 200 },
+      });
+      const result = await fetchWithMsmFallback({ org: 'inherit', site: 'linked-site', daPath: DA_PATH });
+      expect(result.resp.ok).to.equal(true);
+      expect(result.resolvedSite).to.equal('source-site');
+      expect(result.inherited).to.equal(true);
+    });
+
+    it('walks multiple source sites until one holds the file', async () => {
+      stubFetch({
+        org: 'multi',
+        config: [
+          { source: 'source-site', linked: 'mid-site' },
+          { source: 'mid-site', linked: 'linked-site' },
+        ],
+        sources: { 'source-site': 200 },
+      });
+      const result = await fetchWithMsmFallback({ org: 'multi', site: 'linked-site', daPath: DA_PATH });
+      expect(result.resolvedSite).to.equal('source-site');
+      expect(result.inherited).to.equal(true);
+    });
+
+    it('returns the linked-site 404 when there is no MSM config', async () => {
+      stubFetch({ org: 'no-config', config: 404 });
+      const result = await fetchWithMsmFallback({ org: 'no-config', site: 'linked-site', daPath: DA_PATH });
+      expect(result.resp.status).to.equal(404);
+      expect(result.resolvedSite).to.equal('linked-site');
+      expect(result.inherited).to.equal(false);
+    });
+
+    it('returns the linked-site 404 when no source site holds the file', async () => {
+      stubFetch({ org: 'none-have', config: [{ source: 'source-site', linked: 'linked-site' }] });
+      const result = await fetchWithMsmFallback({ org: 'none-have', site: 'linked-site', daPath: DA_PATH });
+      expect(result.resp.status).to.equal(404);
+      expect(result.resolvedSite).to.equal('linked-site');
+      expect(result.inherited).to.equal(false);
+    });
+
+    it('does not fall back on a non-404 error and surfaces the real status', async () => {
+      stubFetch({
+        org: 'forbidden',
+        config: [{ source: 'source-site', linked: 'linked-site' }],
+        sources: { 'linked-site': 403, 'source-site': 200 },
+      });
+      const result = await fetchWithMsmFallback({ org: 'forbidden', site: 'linked-site', daPath: DA_PATH });
+      expect(result.resp.status).to.equal(403);
+      expect(result.resolvedSite).to.equal('linked-site');
+      expect(result.inherited).to.equal(false);
+      // A permission/server error must not trigger a source-site read.
+      expect(configCalls().length).to.equal(0);
+    });
+
+    it('requests the linked site then the source site at the expected DA path', async () => {
+      stubFetch({
+        org: 'url-check',
+        config: [{ source: 'source-site', linked: 'linked-site' }],
+        sources: { 'source-site': 200 },
+      });
+      await fetchWithMsmFallback({ org: 'url-check', site: 'linked-site', daPath: DA_PATH });
+      const requested = globalThis.fetch.args.map(([url]) => url);
+      expect(requested).to.include(`${DA_ADMIN}/source/url-check/linked-site${DA_PATH}`);
+      expect(requested).to.include(`${DA_ADMIN}/source/url-check/source-site${DA_PATH}`);
+    });
+
+    it('forwards fetch opts (headers) to the source request', async () => {
+      stubFetch({ org: 'opts', sources: { 'linked-site': 200 } });
+      const opts = { headers: { 'Cache-Control': 'no-cache' } };
+      await fetchWithMsmFallback({ org: 'opts', site: 'linked-site', daPath: DA_PATH, opts });
+      const sourceCall = globalThis.fetch.args.find(([url]) => url.includes('/source/opts/linked-site/'));
+      expect(sourceCall[1].headers['Cache-Control']).to.equal('no-cache');
+    });
+  });
+});