Bug 2036940

Summary:	oc registry login fails if the file is empty or stdout
Product:	OpenShift Container Platform	Reporter:	Filip Krepinsky <fkrepins>
Component:	oc	Assignee:	Filip Krepinsky <fkrepins>
oc sub component:	oc	QA Contact:	zhou ying <yinzhou>
Status:	CLOSED ERRATA	Docs Contact:
Severity:	low
Priority:	low	CC:	aos-bugs, mfojtik
Version:	4.10
Target Milestone:	---
Target Release:	4.10.0
Hardware:	Unspecified
OS:	Unspecified
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Last Closed:	2022-03-11 18:15:11 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Filip Krepinsky 2022-01-04 13:34:23 UTC

Description of problem:

taken from upstream issue

Since #893, the command oc registry login --kubeconfig=aaa --to=bbb fails if the file bbb is empty:

+(utils.sh:530): write_pull_secret(): oc registry login --kubeconfig=/tmp/kubeconfig--0dZLmzoYmT --to=/tmp/pullsecret--Sm82grIvD0
info: Using registry public hostname registry.ci.openshift.org
error: 1 error occurred:
	* reading JSON file "/tmp/pullsecret--Sm82grIvD0": unmarshaling JSON at "/tmp/pullsecret--Sm82grIvD0": unexpected end of JSON input



Also, argument "-" doesnt't work for --registry-config / --to options 

How reproducible:
100


Expected results:
1. the file bbb should have valid credentials
2. It should be possible to write to stdout