1739922 - Many warnings in TB mochitest log: [JavaScript Warning: " - Unknown scalar."]

Status: NEW

(Thunderbird :: General, defect)

Description

[ISHIKAWA, Chiaki]

Attachment: List s of executed tests, and warning messages that appeared.

I think this is architecture agnostic although I observe the warnings under linux64.
I began seeing this early September.

412 Console message: [JavaScript Warning: " - Unknown scalar."]

(Taken from my summary of latest local log.
412 at the beginning of the warning is the # of frequencies it appeared. )

More than four hundred such warnings surely point to something
wrong. Incorrect Json file? Broken data file?

Found in other people's try-comm-central jobs, too: So I rule out my
local patches as the cause of thss warning.
E.g.
https://firefoxci.taskcluster-artifacts.net/Bq66mAVqTZW9yUsVdbUE4w/0/public/logs/live_backing.log
This is Goeff's job
https://treeherder.mozilla.org/jobs?repo=try-comm-central&selectedTaskRun=Bq66mAVqTZW9yUsVdbUE4w.0&revision=282a50bcb1aff3b343501350c5731bf19d19327c

Attached is the list of test and where the warning appears
created by

egrep "(Unknown scalar.|TEST_START)" log1350-mochitest.txt

The warning seems to come from the following line:
https://searchfox.org/comm-central/source/mozilla/toolkit/components/telemetry/core/TelemetryScalar.cpp#1277

This suggests a problem in telemetry code?