Startup crash on Android 16: AutofillManager NPE inflating actionmain.xml (MaterialSwitch)

[kasnder]

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F-Droid

Describe the bug
ActivityMain fails to start with a NullPointerException inside the platform's AutofillManager construction, triggered while inflating actionmain.xml's MaterialSwitch (swEnabled, layout line 40).

System

• ANDROID_VERSION=16
• USER_APP_START_DATE=2026-08-29T08:32:25.061-04:00
• USER_CRASH_DATE=2026-08-30T08:30:13.737-04:00
• STACK_TRACE_HASH=cc2f9872
• REPORT_ID=0d2a58e7-543b-4152-a394-85524eab6b53

Stack trace

java.lang.RuntimeException: Unable to start activity ComponentInfo{net.kollnig.missioncontrol.fdroid/eu.faircode.netguard.ActivityMain}
	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:5040)
	...
Caused by: android.view.InflateException: Binary XML file line #40 in net.kollnig.missioncontrol.fdroid:layout/actionmain: Error inflating class <unknown>
Caused by: java.lang.reflect.InvocationTargetException
	at android.view.LayoutInflater.createView(LayoutInflater.java:759)
	...
	at eu.faircode.netguard.ActivityMain.onCreate(SourceFile:243)
	...
Caused by: java.lang.NullPointerException: FileDescriptor must not be null
	at android.os.ParcelFileDescriptor.<init>(ParcelFileDescriptor.java:199)
	at android.os.ParcelFileDescriptor$2.createFromParcel(ParcelFileDescriptor.java:1164)
	...
	at android.util.MemoryIntArray.<init>(MemoryIntArray.java:89)
	...
	at android.provider.Settings$NameValueCache.getStringsForPrefixStripPrefix(Settings.java:4419)
	at android.provider.Settings$Config.getStrings(Settings.java:29123)
	at android.provider.SettingsConfigDataStore.getProperties(SettingsConfigDataStore.java:48)
	at android.provider.DeviceConfig.getProperties(DeviceConfig.java:1168)
	at android.provider.DeviceConfig.getBoolean(DeviceConfig.java:1263)
	at android.view.autofill.AutofillFeatureFlags.isFillDialogEnabled(AutofillFeatureFlags.java:446)
	at android.view.autofill.AutofillManager.<init>(AutofillManager.java:978)
	at android.app.SystemServiceRegistry$115.createService(SystemServiceRegistry.java:1704)
	...
	at android.widget.TextView.notifyListeningManagersAfterTextChanged(TextView.java:13654)
	at android.widget.TextView.setText(TextView.java:7961)
	at android.widget.TextView.setText(TextView.java:7729)
	at android.widget.TextView.<init>(TextView.java:2165)
	at android.widget.Button.<init>(Button.java:202)
	at android.widget.CompoundButton.<init>(CompoundButton.java:106)
	at androidx.appcompat.widget.SwitchCompat.<init>(SourceFile:1)
	at com.google.android.material.materialswitch.MaterialSwitch.<init>(SourceFile:11)
	... 28 more

Analysis

This is a platform-level bug, not app code. MaterialSwitch → SwitchCompat → CompoundButton → Button → TextView's constructor unconditionally calls setText(), which calls notifyListeningManagersAfterTextChanged() → getSystemService(AUTOFILL_SERVICE). Constructing AutofillManager reads DeviceConfig, which on this device/build fails while creating a ParcelFileDescriptor from a MemoryIntArray with a null FileDescriptor — an OS-side bug, unrelated to actionmain.xml specifically. Any TextView-family widget inflated on an affected device would trigger it.

No app-side commit currently addresses this; actionmain.xml's MaterialSwitch (swEnabled, lines 33-40) is unchanged. The only realistic mitigation on our side would be wrapping setContentView() in ActivityMain.onCreate() (app/src/main/java/eu/faircode/netguard/ActivityMain.java:243) with a crash guard, though that would only avoid the crash rather than restore the UI, since inflation itself fails.