Add .profm sorting to build.gradle

app/build.gradle

@@ -181,3 +181,35 @@ dependencies {
 ktlint {
     disabledRules.set(["no-wildcard-imports"])
 }
+
+// https://gitlab.com/fdroid/wiki/-/wikis/HOWTO:-diff-&-fix-APKs-for-Reproducible-Builds#differing-assetsdexoptbaselineprofm-easy-to-fix
+// NB: Android Studio can't find the imports; this does not affect the
+// actual build since Gradle can find them just fine.
+import com.android.tools.profgen.ArtProfileKt
+import com.android.tools.profgen.ArtProfileSerializer
+import com.android.tools.profgen.DexFile
+
+project.afterEvaluate {
+    tasks.each { task ->
+        if (task.name.startsWith("compile") && task.name.endsWith("ReleaseArtProfile")) {
+            task.doLast {
+                outputs.files.each { file ->
+                    if (file.name.endsWith(".profm")) {
+                        println("Sorting ${file} ...")
+                        def version = ArtProfileSerializer.valueOf("METADATA_0_0_2")
+                        def profile = ArtProfileKt.ArtProfile(file)
+                        def keys = new ArrayList(profile.profileData.keySet())
+                        def sortedData = new LinkedHashMap()
+                        Collections.sort keys, new DexFile.Companion()
+                        keys.each { key -> sortedData[key] = profile.profileData[key] }
+                        new FileOutputStream(file).with {
+                            write(version.magicBytes$profgen)
+                            write(version.versionBytes$profgen)
+                            version.write$profgen(it, sortedData, "")
+                        }
+                    }
+                }
+            }
+        }
+    }
+}