From 4f384f6f26fb6605854035018d9d8dc71f4d55d1 Mon Sep 17 00:00:00 2001
From: Maksim Kostromin <daggerok@gmail.com>
Date: Thu, 29 Oct 2026 21:14:52 -0400
Subject: [PATCH] fix(updater): a short Yahoo chart never shrinks the published
 history

The shared merge ran only when the Yahoo request had a period1 window, so with the default max a truncated Yahoo answer replaced the published history (2026-10-29: Franklin DVAL and USFI went from 999 rows to one). The merge now runs for every fresh chart; a full max answer starts at inception and comes back unchanged, one that does not join the published days counts as a failed chart and the fund is kept.
---
 scripts/update-data.test.ts | 7 +++++++
 scripts/update-data.ts      | 8 +++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/scripts/update-data.test.ts b/scripts/update-data.test.ts
index e82889e0..acaee96c 100644
--- a/scripts/update-data.test.ts
+++ b/scripts/update-data.test.ts
@@ -1003,6 +1003,13 @@ describe('pipeline 7', () => {
     await s.run({ HISTORY_RANGE: '1y' });
     expect(s.snapshot()).toEqual(first);
     expect(s.meta('AAA').history.totalRows).toBe(400);
+    // a truncated default-range (max) answer never shrinks the history either: one that joins the published days keeps them all,
+    // one of a new day that does not join keeps the fund as published
+    await s.run();
+    expect(s.snapshot()).toEqual(first);
+    s.handler = (url, init) => (url.includes('finance.yahoo.com') ? new Response(JSON.stringify(chartPayload(1, Date.UTC(2026, 9, 25)))) : base(url, init));
+    await s.run();
+    expect(s.meta('AAA').history.totalRows).toBe(400);
   });
 
   test('a relaxed guard still keeps numeric published weights from an all-blank N-PORT sheet (Q24)', async () => {
diff --git a/scripts/update-data.ts b/scripts/update-data.ts
index d4628467..4dd0f263 100755
--- a/scripts/update-data.ts
+++ b/scripts/update-data.ts
@@ -1797,11 +1797,13 @@ async function processFund(fund: CatalogFund, config: UpdaterConfig, previous: J
       const query = yahooChartQuery(config.historyRange);
       const payload = await fetchJson(`${YAHOO_CHART_URL}/${encodeURIComponent(fund.ticker)}?${query.toString()}`, `[ chart    ] ${fund.ticker}`, config, { 'User-Agent': 'Mozilla/5.0' });
       const fetched = parseChart(payload);
-      // A HISTORY_RANGE window never shrinks the published history (and with it 3y, 5y, 10y and since inception); the published
+      // A fresh chart never shrinks the published history (and with it 3y, 5y, 10y and since inception): a HISTORY_RANGE window, and
+      // also a truncated `max` answer (2026-10-29: Yahoo returned 2 bars for Franklin DVAL and USFI). A full `max` answer starts at
+      // inception: nothing older, unchanged. The published
       // distributions table is [Ex-Date, ..., Total Distribution], the window merge reads [date, amount]
       const publishedDistributions = (Array.isArray(previousMeta?.distributions?.rows) ? previousMeta.distributions.rows : []).map((cells: unknown) => (Array.isArray(cells) ? [cells[0], cells[cells.length - 1]] : cells));
-      chart = Number(query.get('period1')) > 0 ? mergeWindowedChart(fetched, previousRows, publishedDistributions) : fetched;
-      if (!chart) throw new Error(`chart window does not join the published history (${config.historyRange})`);
+      chart = mergeWindowedChart(fetched, previousRows, publishedDistributions);
+      if (!chart) throw new Error(`chart does not join the published history (${config.historyRange}, ${fetched.days.length} days)`);
       days = chart.days;
       fresh = fresh || days.length > 0;
     } catch (error) {