work around missing size/nfiles archive metadata, fixes #8491

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 81.75%. Comparing base (9130baf) to head (cea2d58). Report is 7 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #8492 +/- ## ======================================= Coverage 81.75% 81.75% ======================================= Files 73 73 Lines 13112 13112 Branches 1926 1926 ======================================= Hits 10720 10720 Misses 1735 1735 Partials 657 657 ```

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