test(authz): bearer-authed admin cannot edit/cover NULL-uploader mangas (0.87.19)

0.87.10 followup from the rereview. The fix lacked a test for the
specific axis it changed (admin authority via cookie only). New test
mints a bearer for a promoted admin and asserts PATCH/PUT-cover/DELETE-
cover all 403 on NULL-uploader rows. Mutation-confirmed.

Also: `MultipartBuilder::finalize` now `pub` for bearer-multipart use;
`admin_csrf_guard` rustdoc updated to describe the post-0.87.10
cookie-precedence rule.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/tests/api_mangas_metadata.rs

@@ -757,3 +757,125 @@ async fn patch_null_uploader_allowed_for_admin(pool: PgPool) {
         .unwrap();
     assert_eq!(resp.status(), StatusCode::OK);
 }
+
+/// 0.87.10 split `require_can_edit` so admin authority must come via a
+/// session cookie — bearer tokens (bot callers) DO NOT carry admin
+/// powers per the auth-module contract. A bearer-authed admin trying
+/// to PATCH/PUT-cover/DELETE-cover a NULL-`uploaded_by` row must be
+/// rejected. Mechanical revert of `admin_via_session(&session)` to
+/// `user.is_admin` would let bearer-authed admins through and pass
+/// the 0.87.10 cookie tests; this is the missing axis the rereview
+/// asked for.
+#[sqlx::test(migrations = "./migrations")]
+async fn bearer_authed_admin_cannot_edit_null_uploader(pool: PgPool) {
+    let h = common::harness(pool.clone());
+
+    // Catalog row with NULL uploaded_by (the crawler shape).
+    let (_, owner_cookie) = common::register_user(&h.app).await;
+    let created = create_manga(&h.app, &owner_cookie, json!({ "title": "Catalog" })).await;
+    let id = id_of(&created);
+    sqlx::query("UPDATE mangas SET uploaded_by = NULL WHERE id = $1")
+        .bind(id)
+        .execute(&pool)
+        .await
+        .unwrap();
+
+    // Register a user, promote to admin, mint a bearer token from
+    // their session.
+    let (admin_name, admin_cookie) = common::register_user(&h.app).await;
+    let admin = mangalord::repo::user::find_by_username(&pool, &admin_name)
+        .await
+        .unwrap()
+        .unwrap();
+    mangalord::repo::user::set_is_admin_unchecked(&pool, admin.id, true)
+        .await
+        .unwrap();
+    let mint_resp = h
+        .app
+        .clone()
+        .oneshot(common::post_json_with_cookie(
+            "/api/v1/auth/tokens",
+            json!({ "name": "ci-bot" }),
+            &admin_cookie,
+        ))
+        .await
+        .unwrap();
+    assert_eq!(mint_resp.status(), StatusCode::CREATED);
+    let bearer = common::body_json(mint_resp).await["bearer"]
+        .as_str()
+        .unwrap()
+        .to_string();
+
+    // PATCH via bearer — must 403 even though the user behind the
+    // token IS an admin. CurrentUser admits the call, but
+    // `admin_via_session` reads off `Option<CurrentSessionUser>`
+    // which is None on a bearer request.
+    let patch_resp = h
+        .app
+        .clone()
+        .oneshot({
+            let body = json!({ "status": "completed" });
+            axum::http::Request::builder()
+                .method("PATCH")
+                .uri(format!("/api/v1/mangas/{id}"))
+                .header(axum::http::header::CONTENT_TYPE, "application/json")
+                .header(axum::http::header::AUTHORIZATION, format!("Bearer {bearer}"))
+                .body(axum::body::Body::from(body.to_string()))
+                .unwrap()
+        })
+        .await
+        .unwrap();
+    assert_eq!(
+        patch_resp.status(),
+        StatusCode::FORBIDDEN,
+        "bearer-authed admin must NOT be able to PATCH a NULL-uploader manga"
+    );
+
+    // PUT cover via bearer — same gate, same answer.
+    let png = common::fake_png_bytes();
+    let (boundary, body) = common::MultipartBuilder::new()
+        .add_file("cover", "cover.png", "image/png", &png)
+        .finalize();
+    let put_resp = h
+        .app
+        .clone()
+        .oneshot({
+            axum::http::Request::builder()
+                .method("PUT")
+                .uri(format!("/api/v1/mangas/{id}/cover"))
+                .header(
+                    axum::http::header::CONTENT_TYPE,
+                    format!("multipart/form-data; boundary={boundary}"),
+                )
+                .header(axum::http::header::AUTHORIZATION, format!("Bearer {bearer}"))
+                .body(axum::body::Body::from(body))
+                .unwrap()
+        })
+        .await
+        .unwrap();
+    assert_eq!(
+        put_resp.status(),
+        StatusCode::FORBIDDEN,
+        "bearer-authed admin must NOT be able to put_cover on a NULL-uploader manga"
+    );
+
+    // DELETE cover via bearer.
+    let delete_resp = h
+        .app
+        .oneshot(
+            axum::http::Request::builder()
+                .method("DELETE")
+                .uri(format!("/api/v1/mangas/{id}/cover"))
+                .header(axum::http::header::AUTHORIZATION, format!("Bearer {bearer}"))
+                .body(axum::body::Body::empty())
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(
+        delete_resp.status(),
+        StatusCode::FORBIDDEN,
+        "bearer-authed admin must NOT be able to delete_cover on a NULL-uploader manga"
+    );
+}
+

backend/tests/common/mod.rs

@@ -615,7 +615,11 @@ impl MultipartBuilder {
         self.body.extend(b"\r\n");
     }
 
-    fn finalize(self) -> (String, Vec<u8>) {
+    /// Pub so a test can mint a multipart body for a bearer-auth Request
+    /// without going through the cookie helpers. Returns
+    /// `(boundary, body)` ready to attach as `Content-Type:
+    /// multipart/form-data; boundary={boundary}` and the request body.
+    pub fn finalize(self) -> (String, Vec<u8>) {
         let mut body = self.body;
         body.extend(format!("--{}--\r\n", self.boundary).as_bytes());
         (self.boundary, body)