hyperion.ng: Duplicate priorities-update in certain circumstances

2.0.0-alpha.7

• I confirm that this is an issue rather than a question.

Bug report

Under certain circumstances a spurious priorities-update API response is generated.

Steps to reproduce

1. Subscribe to priorities-update (in one terminals):

$ echo '{"command":"serverinfo", "subscribe":["priorities-update"] }' | nc hyperion 19444

1. Set an effect (in another terminal):

$ echo '{"origin": "Home Assistant", "priority": 128, "effect": {"name": "Cold mood blobs"}, "command": "effect"}' | nc hyperion 19444

1. Observe the priority updates in the first terminal.

What is expected?

At most two priority updates (one priority becoming non-visible, another becoming visible).

What is actually happening?

{"command":"priorities-update","data":{"priorities":[{"active":false,"componentId":"EFFECT","origin":"Home Assistant@::ffff:10.100.0.20","owner":"Cold mood blobs","priority":128,"visible":false},{"active":true,"componentId":"V4L","origin":"System","owner":"V4L2:/dev/video0","priority":240,"visible":true}],"priorities_autoselect":true}}
{"command":"priorities-update","data":{"priorities":[{"active":true,"componentId":"EFFECT","origin":"Home Assistant@::ffff:10.100.0.20","owner":"Cold mood blobs","priority":128,"visible":true},{"active":true,"componentId":"V4L","origin":"System","owner":"V4L2:/dev/video0","priority":240,"visible":false}],"priorities_autoselect":true}}
{"command":"priorities-update","data":{"priorities":[{"active":true,"componentId":"EFFECT","origin":"Home Assistant@::ffff:10.100.0.20","owner":"Cold mood blobs","priority":128,"visible":true},{"active":true,"componentId":"V4L","origin":"System","owner":"V4L2:/dev/video0","priority":240,"visible":false}],"priorities_autoselect":true}}

Note the last two updates are identical.

A similar effect can be seen on clear:

$ echo '{"priority": 128, "command": "clear"}' | nc hyperion 19444
{"command":"clear","success":true,"tan":0}

… will then produce two identical updates …

{"command":"priorities-update","data":{"priorities":[{"active":true,"componentId":"V4L","origin":"System","owner":"V4L2:/dev/video0","priority":240,"visible":true}],"priorities_autoselect":true}}
{"command":"priorities-update","data":{"priorities":[{"active":true,"componentId":"V4L","origin":"System","owner":"V4L2:/dev/video0","priority":240,"visible":true}],"priorities_autoselect":true}}

System

Hyperion Server:

• Build: master (GitHub-f719f0b/838092e-1597257777)
• Build time: Aug 19 2020 04:01:56
• Git Remote: https://github.com/hyperion-project/hyperion.ng.git
• Version: 2.0.0-alpha.7
• UI Lang: auto (BrowserLang: en-US)
• UI Access: default
• Avail Capt: dispmanx,v4l2,framebuffer,qt

Hyperion Server OS:

• Distribution: Raspbian GNU/Linux 10 (buster)
• Arch: arm
• Kernel: linux (5.4.51+ (WS: 32))
• Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.135 Safari/53