Lin Wang | Android Efficiency Engineer
It’s a well known reality for Android builders that an app’s manifest (AndroidManifest.xml) holds essential software declarations. It’s not often monitored after being arrange as a result of we assume it hardly modifications. At Pinterest, nonetheless, we now have been actively monitoring the manifest after realizing it does change sometimes.
Whereas constructing an app, Gradle downloads all of the dependent libraries to compile and hyperlink them with the app. These dependent libraries every have their very own mini manifest. Through the construct course of, Android Gradle Plugin (AGP) merges them with the app’s most important manifest to kind the ultimate manifest. Due to this merging course of, the ultimate manifest typically appears to be like fairly completely different from the unique one and incorporates further declarations. Typically, these additional declarations are mandatory for dependent libraries to operate. Nevertheless, typically they’ll have unintended behaviors.
It first caught our consideration throughout a chilly begin regression investigation. We discovered a third get together Software program Growth Package (SDK) declaring a particular ContentProvider in its manifest to heat up itself as early as doable. It is because content material suppliers get initialized very early throughout the software startup, even earlier than the Software’s onCreate() methodology is invoked. Nevertheless, we need to management each third get together libraries’ initialization and solely initialize them when it’s mandatory. Due to this fact, we added the next declaration:
Including this declaration to the manifest will trigger the SdkEarlyInitializer to be faraway from the ultimate merged manifest. This modification resulted in a chilly begin enchancment of 130ms.
From then on, we created the next course of to usually monitor the merged manifest modifications earlier than touchdown a commit, beginning with taking a snapshot of the present merged manifest and retaining it within the codebase:
- As a part of the PR construct, we examine the merged manifest in opposition to the snapshot.
- If a distinction is detected, we fail the construct.
- The PR developer should then regulate the snapshot manifest if the modifications are mandatory, or add the correct “take away” tags to maintain the brand new parts out of the ultimate manifest.
A small group of blocking reviewers will overview each manifest change.
- Found the WorkManagerInitializer (ContentProvider), which was added by the work supervisor library. We firstly eliminated it and notified Google, who finally added assist for initializing the work supervisor with a custom configuration.
- Discovered a brand new intent was added by upgrading of the exoplayer library to 2.15.0. We then contributed to the continued issue discussion with Google to lastly have this pointless intent eliminated.
- Detected the AD_ID permission was added by a library.
- The common cshell diff is ample to check manifests
- AGP does typically reorder the gadgets in manifest with out altering the content material, through which case the snapshot must be adjusted
- Ignoring white areas and newlines is critical
- Incessantly modified gadgets within the manifest must be explicitly ignored (e.g. UUIDs, model codes)
With this strategy, we can be alerted when any new part will get added to our app and really feel extra assured every time we add new dependencies.
Android Efficiency Group: Arun Okay, Ernesto Duhart, Lin Wang, Sheng Liu, Tom Harman
Particular Thanks: Sha Sha Chu (She Her)
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