IssueTracker

We are trying to build our app in a reproducible way. Hopefully, I don't need to explain why this is important. For more information see: https://reproducible-builds.org/

The issue is that recent build-tools (26.x, 27.x and even 28.0.0) introduce small differences into the resources.arsc file. All other APK contents can be build reproducibly as one would expect. Various tools for comparing APKs do not show differences at all. Even aapt2 dump or aapt2 diff don't show differences, but the resources.arsc file itself has differences.

The only clue I was able to find is using aapt dump resources file.apk. This gives a diff like this:

14128,14130c14128,14130
<         resource 0x7f10001c org.package.name:string/abc_toolbar_collapse_description: t=0x03 d=0x000028e5 (s=0x0008 r=0x00)
<         resource 0x7f100143 org.package.name:string/search_menu_title: t=0x03 d=0x000028e2 (s=0x0008 r=0x00)
<         resource 0x7f10016a org.package.name:string/status_bar_notification_info_overflow: t=0x03 d=0x000024bc (s=0x0008 r=0x00)
---
>         resource 0x7f10001c org.package.name:string/abc_toolbar_collapse_description: t=0x03 d=0x000028e7 (s=0x0008 r=0x00)
>         resource 0x7f100143 org.package.name:string/search_menu_title: t=0x03 d=0x000028e4 (s=0x0008 r=0x00)
>         resource 0x7f10016a org.package.name:string/status_bar_notification_info_overflow: t=0x03 d=0x000024e5 (s=0x0008 r=0x00)

Note how the resource IDs are all the same and the only difference is with the d value (whatever this is).

Trying many different things, we were finally able to prevent these differences from occurring when using a special file system that supports deterministic ordering (disorderfs). However, this is not a real solution. Ideally, the resources.arsc file should be created in a deterministic fashion. I am hoping for your help to achieve this. Thanks!

Further Information: We are using the following configuration in our build.gradle file:

android {
        buildTypes {
                release {
                        shrinkResources true
                        minifyEnabled true
                        crunchPngs false
                }
        }
}

We set the latter to false, because crunching PNGs is not always done deterministically as well.