PDF datafile without thumbnail results in (logged) 500 error

[donsizemore]

What steps does it take to reproduce the issue?

Upload a PDF either a) above the PDF thumbnail filesize threshold, or b) without the /usr/bin/convert binary present.

• When does this issue occur?

One page load (or, more precisely, API call).

• Which page(s) does it occurs on?

dataset.xhtml

• What happens?

Payara logs

[2023-12-12T15:35:26.025+0000] [Payara 6.2023.7] [SEVERE] [] [edu.harvard.iq.dataverse.api.errorhandlers.ThrowableHandler] [tid: _ThreadID=87 _ThreadName=http-thread-pool::jk-connector(2)] [timeMillis: 1702395326025] [levelValue: 1000] [[
  _status="ERROR";_code=500;_message="Internal server error. More details available at the server logs.";_incidentId="2a462a10-2539-4843-88f2-d921ebd7db04";_interalError="NullPointerException";_requestUrl="https://beta.dataverse.org/api/v1/access/datafile/70?imageThumb=
400";_requestMethod="GET"|]]

[2023-12-12T15:35:26.026+0000] [Payara 6.2023.7] [SEVERE] [] [edu.harvard.iq.dataverse.api.errorhandlers.ThrowableHandler] [tid: _ThreadID=87 _ThreadName=http-thread-pool::jk-connector(2)] [timeMillis: 1702395326026] [levelValue: 1000] [[
  java.lang.NullPointerException: Cannot invoke "edu.harvard.iq.dataverse.dataaccess.StorageIO.setNoVarHeader(boolean)" because "storageIO" is null
        at edu.harvard.iq.dataverse.api.DownloadInstanceWriter.writeTo(DownloadInstanceWriter.java:277)
        at edu.harvard.iq.dataverse.api.DownloadInstanceWriter.writeTo(DownloadInstanceWriter.java:61)

• To whom does it occur (all users, curators, superusers)?

All users.

• What did you expect to happen?

No NPE

Which version of Dataverse are you using?

develop (6.1 as of this writing)

Any related open or closed issues to this bug report?

Not that I can find.

@qqmyers has a fix already at QDR; will attempt to cherry-pick into a PR to close this issue.