EXPORT. OVERLEAF Invalid format of field 'urldate'

edited September 14, 2018
I have been using my Zotero bibliography in Overleaf for quite some time with no problems what so ever.

Until I started getting several messages of error like this one in Overleaf:

./main.bbl:
Package biblatex Warning: Biber reported the following issues
(biblatex) with 'appelgren_data_2014':
(biblatex) - Invalid format of field 'urldate'.


I have no idea how to fix it. I've tried to change the 'date' reference for some of the references directly on Zotero (from 'mdy' to 'y'). It seems to have worked, but it is a lot of trouble to do that with all the references. Besides, I don't want to lose this kind of information from Zotero.

Advices?
  • urldate is the accessed date, not the regular date in Zotero. Best I can tell, that's exporting correctly in the form YYYY-MM-DD to biblatex, both form the client and via API (which is where Overleaf gets it). Are you able to see the .bib file Overleaf is trying to use when compiling. And you have overleaf selected to use biblatex/biber, right?
  • Opened the .bib file. All urldates had 'TZ' in the end, like this {2018-09-14TZ}. Do you know why? Anyways, just deleted the .bib file and sync again with zotero. It worked. Thank you.
  • I have no idea why that would have happened, sorry. It's nowhere in the code. Either a glitch in the Zotero API or a glitch in Overleaf's sync with it. Don't think we'll be able to tell unless this happens again, which it hopefully won't.
  • I have the same problem with urldates. In the .bib file I am exporting from zotero, there is TZ in the end of the urldates. Is there any bugfix planned on this?
  • Is this using direct Overleaf integration or import/export?
  • it happens only when I use a .bib file from direct integration to Overleaf
  • I'm not seeing this in any export from the Zotero API I can produce. Could you please report this to Overleaf and point them to this thread in case they need to follow up? It's possible there's a Zotero bug, but we'd need to know the API call they're making to produce the TZ at the end of urldate.
  • thank you for your reply, I will report it to Overleaf
  • they said that they use directly Zotero Web Exporter API and they are not modifying anything. They suggested me to export the .bib file from Zotero Desktop exporter as a workaround. I am not sure if they will follow up this thread, they just told me that they cannot do anything about it.
  • What happens when you do export the same item from Zotero, either as bibtex or as biblatex?
  • If I export from Zotero Desktop, the .bib file doesn't have TZ in the urldates
  • Are you using bibtex or biblatex in Overleaf?

    - If using bibtex, go to "My LIbrary" here on the page, select the item in question, click on the "Export" (folder with green arrow) button at the top right, select bibtex as format and see if the TZ is in that export

    - If using biblatex, do the same thing, but instead of clicking, copy the link. It will look something like this: https://www.zotero.org/api/users/2433/items/top?limit=25&format=bibtex&key=[someRandomLetters]&v=1
    Change bibtex to biblatex and paste the link into your browser and see what that output looks like. (make sure to not post your key, the part that I have substituted with [someRandomLetters] here)
  • Following your instructions, I don't have TZ in the output neither for bibtex nor biblatex
  • I'd take this back to Overleaf then -- it's still _possible_ this is a Zotero issue, but if the Zotero API doesn't produce the same error when queried directly, (and also given that the only two people who have ever reported this are Overleaf users) this really suggests it's on their end. At a minimum it'd be helpful if they would help us replicate the exact API calls that are causing this.
  • More for my sake, if any one of you have BBT installed, could you see if it also exports dates this way? What is in the access date field?
  • @emilianoeheyns no, it doesn't, urldate looks fine (i.e. in ISO format) for BBT.

    (but just to repeat, we also haven't seen a single example of this in Zotero; this has only ever appeared in Overleaf's Zotero integration)
  • My urldate field in Zotero also contains the time as in "2019-05-22 21:28:03" and shows up in Overleaf as "2019-05-22TZ". However if I remove the time and keep "2019-05-22" Overleaf correctly parses the date. There is probably something wrong with how Overleaf handles the time part.
  • Great, thanks, I was actually able to replicate this in Zotero now.

    @dstillman this appears to be a regression in v3 of the API:
    https://api.zotero.org/groups/684844/items/65R5MEPB?format=bibtex&v=1 is fine but

    https://api.zotero.org/groups/684844/items/65R5MEPB?format=bibtex&v=3

    (or just https://api.zotero.org/groups/684844/items/65R5MEPB?format=bibtex , which is equivalent of course)

    produces urldate = {2019-02-18TZ},
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