From 0adaeccd0dd0cb80c30cf8bcb035004906c93cba Mon Sep 17 00:00:00 2001
From: Vlad0n20 <vlad.onischuk1234@gmail.com>
Date: Mon, 24 Aug 2026 17:00:09 +0200
Subject: [PATCH] fix(preprints): version-pin pdf render url to prevent stale
 cache on recovered preprints

---
 .../preprint-file-section.component.spec.ts   | 41 +++++++++++++++++++
 .../preprint-file-section.component.ts        |  7 +++-
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/src/app/features/preprints/components/preprint-details/preprint-file-section/preprint-file-section.component.spec.ts b/src/app/features/preprints/components/preprint-details/preprint-file-section/preprint-file-section.component.spec.ts
index 5b90f6653..3cc3b1684 100644
--- a/src/app/features/preprints/components/preprint-details/preprint-file-section/preprint-file-section.component.spec.ts
+++ b/src/app/features/preprints/components/preprint-details/preprint-file-section/preprint-file-section.component.spec.ts
@@ -116,6 +116,47 @@ describe('PreprintFileSectionComponent', () => {
     expect(component.safeLink()).toBeNull();
   });
 
+  it('should pin the safe link to the latest file version to bust stale MFR/CDN caches', () => {
+    const downloadUrl = 'https://files.osf.io/v1/resources/abc/providers/osfstorage/def';
+    setup({
+      selectorOverrides: [
+        {
+          selector: PreprintSelectors.getPreprintFile,
+          value: {
+            ...mockFile,
+            links: { ...mockFile.links, render: `https://mfr.osf.io/render?url=${encodeURIComponent(downloadUrl)}` },
+          },
+        },
+      ],
+    });
+
+    const safeLink = component.safeLink();
+    const nestedDownloadUrl = new URL(new URL(safeLink!).searchParams.get('url')!);
+
+    expect(nestedDownloadUrl.searchParams.get('version')).toBe('1');
+  });
+
+  it('should not add a version param when there are no file versions yet', () => {
+    const downloadUrl = 'https://files.osf.io/v1/resources/abc/providers/osfstorage/def';
+    setup({
+      selectorOverrides: [
+        {
+          selector: PreprintSelectors.getPreprintFile,
+          value: {
+            ...mockFile,
+            links: { ...mockFile.links, render: `https://mfr.osf.io/render?url=${encodeURIComponent(downloadUrl)}` },
+          },
+        },
+        { selector: PreprintSelectors.getPreprintFileVersions, value: [] },
+      ],
+    });
+
+    const safeLink = component.safeLink();
+    const nestedDownloadUrl = new URL(new URL(safeLink!).searchParams.get('url')!);
+
+    expect(nestedDownloadUrl.searchParams.has('version')).toBe(false);
+  });
+
   it('should compute version menu items from file versions', () => {
     setup();
     const menuItems = component.versionMenuItems();
diff --git a/src/app/features/preprints/components/preprint-details/preprint-file-section/preprint-file-section.component.ts b/src/app/features/preprints/components/preprint-details/preprint-file-section/preprint-file-section.component.ts
index 8b81a88a3..b3f814fd5 100644
--- a/src/app/features/preprints/components/preprint-details/preprint-file-section/preprint-file-section.component.ts
+++ b/src/app/features/preprints/components/preprint-details/preprint-file-section/preprint-file-section.component.ts
@@ -14,6 +14,7 @@ import { ProviderReviewsWorkflow } from '@osf/features/preprints/enums';
 import { PreprintSelectors } from '@osf/features/preprints/store/preprint';
 import { LoadingSpinnerComponent } from '@osf/shared/components/loading-spinner/loading-spinner.component';
 import { IS_LARGE, IS_MEDIUM } from '@osf/shared/helpers/breakpoints.tokens';
+import { getMfrUrlWithVersion } from '@osf/shared/helpers/mfr-url.helper';
 import { SafeUrlPipe } from '@osf/shared/pipes/safe-url.pipe';
 import { DataciteService } from '@osf/shared/services/datacite/datacite.service';
 
@@ -43,7 +44,11 @@ export class PreprintFileSectionComponent {
   fileVersions = select(PreprintSelectors.getPreprintFileVersions);
   areFileVersionsLoading = select(PreprintSelectors.arePreprintFileVersionsLoading);
 
-  safeLink = computed(() => this.file()?.links.render ?? null);
+  safeLink = computed(() => {
+    const latestVersionId = this.fileVersions()?.[0]?.id ?? '';
+
+    return getMfrUrlWithVersion(this.file()?.links.render, latestVersionId);
+  });
   isIframeLoading = true;
 
   versionMenuItems = computed(() => {