1881833 - large volume of attribution DecodeErrors from msix builds

Status: NEW

(Firefox :: Installer, defect, P3)

Description

[[e-mail] (:bhearsum)]

I noticed today that we have an ever increasing amount of attribution DecodeErrors from our MSIX builds. As best I can tell, it began in late August 2023, with Firefox 117. I can't find anything of note that shipped with that, though. Across nsWindowsPackageManager.cpp and AttributionCode.sys.mjs, the only changesets I find that shipped with 117 are https://hg.mozilla.org/mozilla-central/rev/c14cfd2a196d8e7f14bcb5e7438202089b2c8346 and https://hg.mozilla.org/mozilla-central/rev/bd568ad893882d37f094d43cba3f62c78982cd05 - neither of which seem likely to be at fault.

Comment 1

[Michael Hughes]

The DecodeErrors can be because either a key in the attribution data is not known or because of a decode error.
As a first step, we should probably differentiate between these two so that we can figure out if we're getting weird urls with extra data or if stored data on disk is getting corrupted somehow.
We could probably also add a checksum to the cached attribution data file, so we can ensure it hasn't been accidentally tampered with by anything.