From e0f3f00b3a90d4f88397a188c5983ea3b1785906 Mon Sep 17 00:00:00 2001
From: Meta Vens <rwvens@hotmail.com>
Date: Sun, 30 Aug 2026 23:15:54 +0200
Subject: [PATCH] Ignore checkout timestamps during source sync

---
 packages/rag/src/source-document-archive.ts |  1 -
 scripts/smoke-source-rag-commit-boundary.ts | 14 +++++++++++---
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/packages/rag/src/source-document-archive.ts b/packages/rag/src/source-document-archive.ts
index 1c50804..cc58fd9 100644
--- a/packages/rag/src/source-document-archive.ts
+++ b/packages/rag/src/source-document-archive.ts
@@ -434,7 +434,6 @@ function comparableFields(document: ArchivedSourceDocumentRecord): Record<string
     language: document.language,
     title: document.title,
     content: document.content,
-    lastModifiedAt: document.lastModifiedAt,
     metadata: document.metadata ?? {},
   };
 }
diff --git a/scripts/smoke-source-rag-commit-boundary.ts b/scripts/smoke-source-rag-commit-boundary.ts
index 072bd2b..12d8c43 100644
--- a/scripts/smoke-source-rag-commit-boundary.ts
+++ b/scripts/smoke-source-rag-commit-boundary.ts
@@ -25,10 +25,17 @@ async function main(): Promise<void> {
 
   try {
     const archive = new FileSourceDocumentArchiveRepository(archivePath);
-    const original = document("original body");
-    const updated = document("updated body");
+    const original = document("original body", "2026-06-03T00:00:00.000Z");
+    const updated = document("updated body", "2026-08-30T00:00:00.000Z");
     await archive.syncRepoDocuments("Fixture", [original]);
 
+    const timestampOnlyPlan = await archive.planRepoDocuments(
+      "Fixture",
+      [document("original body", "2026-08-30T00:00:00.000Z")],
+    );
+    assertEqual(timestampOnlyPlan.changedSourceIds.length, 0, "checkout timestamp changed document identity");
+    assertEqual(timestampOnlyPlan.unchanged, 1, "checkout timestamp did not remain observational");
+
     const failingPipeline = new SourceRagPipeline(
       archive,
       new SourceDocumentIngester(),
@@ -70,12 +77,13 @@ void main().catch((error) => {
   process.exitCode = 1;
 });
 
-function document(content: string): ArchivedSourceDocument {
+function document(content: string, lastModifiedAt?: string): ArchivedSourceDocument {
   return {
     id: sourceId,
     repoName: "Fixture",
     path: "README.md",
     content,
+    lastModifiedAt,
   };
 }