Android 11.5a10-build2 is not reproducible

See #40462 (comment 2799592) and earlier comments.

Possible cause is Nimbus FML plugin.

assigned to @sysrqb

marked this issue as related to #40462 (closed)

mentioned in issue #40462 (closed)

(For the record, I believe FML is an acronym of Feature Manifest Language)

We have progress here. I detailed the investigation in https://gitlab.torproject.org/tpo/applications/tor-browser/-/wikis/Reproducible-Builds/Debugging-Android as a "case study" for how someone might do this - and for a future soul that must investigate a non-reproducible build.

The summary is that we hit two distinct reproducibility issues:

1. Code generation for Nimbus
2. Code generation for Glean

The code generation in Nimbus is a new addition, leveraging Mozilla's new Nimbus FML. The definitions are in fenix's nimbus.fml.yml file, and that file is parsed and code is generated by the Nimbus FML (gradle) plugin. Following our solution for #40293 (closed), we can solve this by substituting HashMap with BTreeMap. This patch can likely be upstreamed.

The second issue is slightly more complicated, but the solution is simpler. We already know that glean-parser is responsible for code generation related to Glean's telemetry. After digging into this new issue I found that Mozilla introduced a build timestamp in the code generation (boo!), but they also implemented a way to inject a timestamp (yay!). We solve this using the latter.

mentioned in merge request !446 (closed)

added 5h of time spent

added Doing label

Seems this is fixed and landed as aa756d03

We can re-open this issue if this problem isn't solved.

closed

mentioned in issue #40582 (closed)

marked this issue as related to tor-browser#41733 (closed)

mentioned in issue tor-browser#41733 (closed)