id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,pull_request,body,repo,type,active_lock_reason,performed_via_github_app,reactions,draft,state_reason
518725064,MDU6SXNzdWU1MTg3MjUwNjQ=,29,`import` command fails on empty files,21148,closed,0,,,4,2019-11-06T20:34:26Z,2019-11-09T20:33:38Z,2019-11-09T19:36:36Z,CONTRIBUTOR,,"If a file in the export is empty (in my case it was `account-suspensions.js`), `twitter-to-sqlite import` fails:

```
$ twitter-to-sqlite import twitter.db ~/Downloads/twitter-2019-11-06-926f4f3be4b3b1fcb1aa387c40cd14f7c8aaf9bbcdb2d78ac14d9989add501bb.zip
Traceback (most recent call last):
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/bin/twitter-to-sqlite"", line 10, in <module>
    sys.exit(cli())
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/click/core.py"", line 764, in __call__
    return self.main(*args, **kwargs)
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/click/core.py"", line 717, in main
    rv = self.invoke(ctx)
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/click/core.py"", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/click/core.py"", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/click/core.py"", line 555, in invoke
    return callback(*args, **kwargs)
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/twitter_to_sqlite/cli.py"", line 627, in import_
    archive.import_from_file(db, filename, content)
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/twitter_to_sqlite/archive.py"", line 224, in import_from_file
    db[table_name].upsert_all(rows, hash_id=""pk"")
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/sqlite_utils/db.py"", line 1113, in upsert_all
    extracts=extracts,
  File ""/Users/jacob/Library/Caches/pypoetry/virtualenvs/jkm-dogsheep-ezLnyXZS-py3.7/lib/python3.7/site-packages/sqlite_utils/db.py"", line 980, in insert_all
    first_record = next(records)
StopIteration
```

This appears to be because `db.upsert_all` is called with no rows -- I think? 

I hacked around this by modifying `import_from_file` to have an `if rows:` clause:

```
    for table, rows in to_insert.items():
        if rows:
            table_name = ""archive_{}"".format(table.replace(""-"", ""_""))
            ...
```

I'm happy to work up a real PR if that's the right approach, but I'm not sure it is.",206156866,issue,,,"{""url"": ""https://api.github.com/repos/dogsheep/twitter-to-sqlite/issues/29/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed