Handle opening a version should rediect to head

src-ui/src/app/components/document-detail/document-detail.component.ts

@@ -437,6 +437,7 @@ export class DocumentDetailComponent
   }
 
   private loadDocument(documentId: number): void {
+    let redirectedToHead = false
     this.selectedVersionId = documentId
     this.previewUrl = this.documentsService.getPreviewUrl(
       this.selectedVersionId
@@ -459,7 +460,24 @@ export class DocumentDetailComponent
     this.documentsService
       .get(documentId)
       .pipe(
-        catchError(() => {
+        catchError((error) => {
+          if (error?.status === 404) {
+            return this.documentsService.getHeadId(documentId).pipe(
+              map((result) => {
+                const headId = result?.head_id
+                if (headId && headId !== documentId) {
+                  const section =
+                    this.route.snapshot.paramMap.get('section') || 'details'
+                  redirectedToHead = true
+                  this.router.navigate(['documents', headId, section], {
+                    replaceUrl: true,
+                  })
+                }
+                return null
+              }),
+              catchError(() => of(null))
+            )
+          }
           // 404 is handled in the subscribe below
           return of(null)
         }),
@@ -470,6 +488,9 @@ export class DocumentDetailComponent
       .subscribe({
         next: (doc) => {
           if (!doc) {
+            if (redirectedToHead) {
+              return
+            }
             this.router.navigate(['404'], { replaceUrl: true })
             return
           }

src-ui/src/app/services/rest/document.service.ts

@@ -211,6 +211,12 @@ export class DocumentService extends AbstractPaperlessService<Document> {
     })
   }
 
+  getHeadId(documentId: number) {
+    return this.http.get<{ head_id: number }>(
+      this.getResourceUrl(documentId, 'head')
+    )
+  }
+
   deleteVersion(headDocumentId: number, versionId: number) {
     return this.http.delete<{ result: string; current_version_id: number }>(
       this.getResourceUrl(headDocumentId, `versions/${versionId}`)

src/documents/views.py

@@ -805,6 +805,26 @@ class DocumentViewSet(
         )
         return super().get_serializer(*args, **kwargs)
 
+    @action(methods=["get"], detail=True, url_path="head")
+    def head(self, request, pk=None):
+        try:
+            doc = Document.global_objects.select_related(
+                "owner",
+                "head_version",
+            ).get(pk=pk)
+        except Document.DoesNotExist:
+            raise Http404
+
+        head_doc = doc if doc.head_version_id is None else doc.head_version
+        if request.user is not None and not has_perms_owner_aware(
+            request.user,
+            "view_document",
+            head_doc,
+        ):
+            return HttpResponseForbidden("Insufficient permissions")
+
+        return Response({"head_id": head_doc.id})
+
     def update(self, request, *args, **kwargs):
         response = super().update(request, *args, **kwargs)
         from documents import index