jq with curl fails if select filter is used -

i'm piping curl output jq: https://stedolan.github.io/jq/ , works great until try use select filter.

this filter works fine when in online tool: https://jqplay.org/ , in command line experiments after having downloaded file.

this issue occurs when try directly pipe curl output jq.

this fails:

i71178@slcits-l2222:~/next-gen/mongodb$ curl 'http://fhirtest.uhn.ca/basedstu3/patient?_format=json&_count=50&_pretty=false&_summary=data' | jq-linux64 --unbuffered -r -c '.link[] | select(.relation == next) | .url' | head -3 jq: error: next/0 not defined @ <top-level>, line 1: .link[] | select(.relation == next) | .url                               jq: 1 compile error   % total    % received % xferd  average speed   time    time     time  current                                  dload  upload   total   spent    left  speed 100  2421    0  2421    0     0   2413      0 --:--:--  0:00:01 --:--:--  2413 curl: (23) failed writing body (1675 != 2736) i71178@slcits-l2222:~/next-gen/mongodb$  

this works fine:

i71178@slcits-l2222:~/next-gen/mongodb$ curl 'http://fhirtest.uhn.ca/basedstu3/patient?_format=json&_count=50&_pretty=false&_summary=data' | jq-linux64 --unbuffered -r -c '.link[] | .url' | head -3  % total    % received % xferd  average speed   time    time     time  current                                  dload  upload   total   spent    left  speed 100 46801    0 46801    0     0  66256      0 --:--:-- --:--:-- --:--:-- 66290 http://fhirtest.uhn.ca/basedstu3/patient?_count=50&_format=json&_pretty=false&_summary=data http://fhirtest.uhn.ca/basedstu3?_getpages=e73ba3b4-cc7e-4028-8679-b5da1f9cbdd1&_getpagesoffset=50&_count=50&_format=json&_bundletype=searchset i71178@slcits-l2222:~/next-gen/mongodb$  

for context, being pipes select filter:

i71178@slcits-l2222:~/next-gen/mongodb$ curl 'http://fhirtest.uhn.ca/basedstu3/patient?_format=json&_count=50&_pretty=false&_summary=data' | jq-linux64 --unbuffered -r -c '.link[]' | head -3   % total    % received % xferd  average speed   time    time     time  current                                  dload  upload   total   spent    left  speed 100 46801    0 46801    0     0  64411      0 --:--:-- --:--:-- --:--:-- 64375 {"relation":"self","url":"http://fhirtest.uhn.ca/basedstu3/patient?_count=50&_format=json&_pretty=false&_summary=data"} {"relation":"next","url":"http://fhirtest.uhn.ca/basedstu3?_getpages=00952912-c9ab-47ca-826c-200bddffe617&_getpagesoffset=50&_count=50&_format=json&_bundletype=searchset"} i71178@slcits-l2222:~/next-gen/mongodb$  

i appreciate here.

thanks!

the problem evidently select filter:

 select(.relation == next) 

i think meant:

select(.relation == "next") 

safer be:

select(.relation? == "next")