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
527710055,MDU6SXNzdWU1Mjc3MTAwNTU=,640,Nicer error message for heroku publish name clash,82988,open,0,,,1,2019-11-24T14:57:07Z,2019-12-06T07:19:34Z,,CONTRIBUTOR,,"If you try to publish to Heroku using no set name (i.e. the default `datasette` name) and a project already exists under that name, you get a meaningful error report on the first line followed by Py error messages that drown it out:

```
Creating datasette... !
 ▸    Name datasette is already taken
Traceback (most recent call last):
  File ""/usr/local/bin/datasette"", line 10, in <module>
    sys.exit(cli())
  File ""/usr/local/lib/python3.7/site-packages/click/core.py"", line 764, in __call__
    return self.main(*args, **kwargs)
  File ""/usr/local/lib/python3.7/site-packages/click/core.py"", line 717, in main
    rv = self.invoke(ctx)
  File ""/usr/local/lib/python3.7/site-packages/click/core.py"", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File ""/usr/local/lib/python3.7/site-packages/click/core.py"", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File ""/usr/local/lib/python3.7/site-packages/click/core.py"", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File ""/usr/local/lib/python3.7/site-packages/click/core.py"", line 555, in invoke
    return callback(*args, **kwargs)
  File ""/Users/NNNNN/Library/Python/3.7/lib/python/site-packages/datasette/publish/heroku.py"", line 124, in heroku
    create_output = check_output(cmd).decode(""utf8"")
  File ""/usr/local/Cellar/python/3.7.5/Frameworks/Python.framework/Versions/3.7/lib/python3.7/subprocess.py"", line 411, in check_output
    **kwargs).stdout
  File ""/usr/local/Cellar/python/3.7.5/Frameworks/Python.framework/Versions/3.7/lib/python3.7/subprocess.py"", line 512, in run
    output=stdout, stderr=stderr)
subprocess.CalledProcessError: Command '['heroku', 'apps:create', 'datasette', '--json']' returned non-zero exit status 1.
```

It would be neater if:

- the Py error message was caught;
- the report suggested setting a project name using `-n` etc.

It may also be useful to provide a command to list the current names that are being used, which I assume is available via a Heroku call?",107914493,issue,,,"{""url"": ""https://api.github.com/repos/simonw/datasette/issues/640/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,