NPE: `Attempt to invoke virtual method 'java.lang.String com.owncloud.android.datamodel.OCFile.getEtag()'` via `checkForChanges`

[acress1]

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Hi, I've got this error message in the Android app:

Cause of error

Exception in thread "Syncfolder thread" java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.owncloud.android.datamodel.OCFile.getEtag()' on a null object reference
    at com.owncloud.android.operations.SynchronizeFolderOperation.checkForChanges(SynchronizeFolderOperation.java:169)
    at com.owncloud.android.operations.SynchronizeFolderOperation.run(SynchronizeFolderOperation.java:127)
    at com.owncloud.android.lib.common.operations.RemoteOperation.execute(RemoteOperation.java:193)
    at com.owncloud.android.services.SyncFolderHandler.doOperation(SyncFolderHandler.java:106)
    at com.owncloud.android.services.SyncFolderHandler.handleMessage(SyncFolderHandler.java:79)
    at android.os.Handler.dispatchMessage(Handler.java:107)
    at android.os.Looper.loopOnce(Looper.java:232)
    at android.os.Looper.loop(Looper.java:317)
    at android.os.HandlerThread.run(HandlerThread.java:85)

App information

• ID: com.nextcloud.client
• Version: 30300190
• Build flavor: generic

Device information

• Brand: OnePlus
• Device: OnePlus5T
• Model: ONEPLUS A5010
• Id: AP2A.240905.003
• Product: OnePlus5T

Firmware

• SDK: 34
• Release: 14
• Incremental: 0c7a9b4c4c

[z3ntu]

Also just saw this crash on the same version, while trying to stop https://github.com/nextcloud/android/issues/13738

[strugee]

I've just hit this on version 30300290. It happened literally while I was removing entries from the "internal 2-way sync" section in the app settings.

[AndyScherzinger]

CC @alperozturk96

[stilley2]

Seeing this with 3.30.4 as well