Log messages in the 'VisualEditor' channel are not recorded in Kibana if any extra data ($context array) is passed.
I discovered this after SWAT-ting these two patches: https://gerrit.wikimedia.org/r/q/Ide5138d8f8f462b9c3d7da10f26ff57c9d17f1c9 https://gerrit.wikimedia.org/r/q/I0f321df057068e1dd396a04a9e194853c2b0e9e4 (debug logging for T233320 and T233127)
And seeing nothing in this Kibana search: https://logstash.wikimedia.org/goto/4d053e9de35d9fccb40fabcabd46ff00
@Jdforrester-WMF and @Krinkle helped me experiment, deploying several versions of this patch to mwdebug1002 and testing what gets logged: https://gerrit.wikimedia.org/r/c/mediawiki/extensions/VisualEditor/+/540464
In the end, I found out that things are only logged if the $context parameter is not given or empty: https://gerrit.wikimedia.org/r/c/mediawiki/extensions/VisualEditor/+/540464/3/includes/ApiVisualEditorEdit.php#281
And changed our actual debug logging to put all the extra data in the message: https://gerrit.wikimedia.org/r/q/Iae778f95774df2e24b30387221e39e097e25a4cf, which immediately resulted in them being logged properly (they are now visible in the same search I linked).
However this is obviously quite inconvenient to work with. Can anyone help investigate why this happens?