2028892 - Labeled test_get_value reports values for invalid labels

Status: RESOLVED FIXED

(Data Platform and Tools :: Glean: SDK, defect, P1)

Description

[Chris H-C :chutten]

In bug 1930572 we added testGetValue directly on labeled_* metrics so you no longer had to check each submetric's value individually (and to help power about:glean).

Unfortunately, there's a bug in LabeledMetric where any label that gets mapped to __other__ (for being not in the static list, or being more than the 16 allowed per ping) gets retained in the metric instance's label_map, each pointing to its own instance of a submetric for __other__. This leads to some surprising behaviours, e.g. for a labeled_counter metric with one static label in its definition (say, label_1), adding to labels invalid_1 the value of 1 and invalid_2 the value of 2 will result in a response from test_get_value of {invalid_1: 3, invalid_2: 3}.

This is incorrect, and should instead be {__other__: 3}.

The values in the db and reported in pings are correct, and the behaviour of asking submetrics for their values individually also remains correct.

Comment 1

[BMO Github Automation]

Attachment: [mozilla/glean] bug 2028892 - Fix Labeled's test_get_value for `__other__` labels (#3429)

Comment 2

[Chris H-C :chutten]

chutten merged PR [mozilla/glean]: bug 2028892 - Fix Labeled's test_get_value for other labels (#3429Edit title) in efc0a59.