Fix crash when refreshing feed after importing database or subscriptions

[TobiGr]

What is it?

• Bugfix (user facing)
• Feature (user facing)
• Codebase improvement (dev facing)
• Meta improvement to the project (dev facing)

Description of the changes in your PR

Close database before restarting the app

Fixes the following issue(s)

Fixes crash when refreshing feed after importing database or subscriptions.

Exception

• User Action: requested feed
• Request: Loading feed
• Content Country: US
• Content Language: en
• App Language: en_GB
• Service: none
• Version: 0.21.6
• OS: Linux Android 10 - 29

Crash log

java.lang.NullPointerException: Attempt to invoke virtual method 'void org.schabi.newpipe.database.subscription.SubscriptionEntity.setName(java.lang.String)' on a null object reference
	at org.schabi.newpipe.local.subscription.SubscriptionManager.updateFromInfo(SubscriptionManager.kt:73)
	at org.schabi.newpipe.local.feed.service.FeedLoadService$databaseConsumer$1$1.run(FeedLoadService.kt:324)
	at androidx.room.RoomDatabase.runInTransaction(RoomDatabase.java:556)
	at org.schabi.newpipe.local.feed.service.FeedLoadService$databaseConsumer$1.accept(FeedLoadService.kt:316)
	at org.schabi.newpipe.local.feed.service.FeedLoadService$databaseConsumer$1.accept(FeedLoadService.kt:65)
	at io.reactivex.rxjava3.internal.operators.flowable.FlowableDoOnEach$DoOnEachSubscriber.onNext(FlowableDoOnEach.java:86)
	at io.reactivex.rxjava3.internal.operators.flowable.FlowableBuffer$PublisherBufferExactSubscriber.onNext(FlowableBuffer.java:124)
	at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$ObserveOnSubscriber.runAsync(FlowableObserveOn.java:402)
	at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.run(FlowableObserveOn.java:176)
	at io.reactivex.rxjava3.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:65)
	at io.reactivex.rxjava3.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:56)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:301)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
	at java.lang.Thread.run(Thread.java:919)

APK testing

The APK can be found by going to the "Checks" tab below the title. On the left pane, click on "CI", scroll down to "artifacts" and click "app" to download the zip file which contains the debug APK of this PR.

Due diligence

• I read the contribution guidelines.

[XiangRongLin]

With those changes I get this, after importing the db

Exception

• User Action: requested feed
• Request: Loading feed
• Content Country: US
• Content Language: en-US
• App Language: en_US
• Service: none
• Version: 0.21.5
• OS: Linux Android 11 - 30

Crash log

java.lang.IllegalStateException: The database '/data/user/0/org.schabi.newpipe.debug/databases/newpipe.db' is not open.
	at android.database.sqlite.SQLiteDatabase.throwIfNotOpenLocked(SQLiteDatabase.java:2482)
	at android.database.sqlite.SQLiteDatabase.createSession(SQLiteDatabase.java:430)
	at android.database.sqlite.-$$Lambda$RBWjWVyGrOTsQrLCYzJ_G8Uk25Q.get(Unknown Source:2)
	at java.lang.ThreadLocal$SuppliedThreadLocal.initialValue(ThreadLocal.java:284)
	at java.lang.ThreadLocal.setInitialValue(ThreadLocal.java:180)
	at java.lang.ThreadLocal.get(ThreadLocal.java:170)
	at android.database.sqlite.SQLiteDatabase.getThreadSession(SQLiteDatabase.java:424)
	at android.database.sqlite.SQLiteProgram.getSession(SQLiteProgram.java:104)
	at android.database.sqlite.SQLiteStatement.executeUpdateDelete(SQLiteStatement.java:66)
	at androidx.sqlite.db.framework.FrameworkSQLiteStatement.executeUpdateDelete(FrameworkSQLiteStatement.java:46)
	at org.schabi.newpipe.database.feed.dao.FeedDAO_Impl.unlinkOldLivestreams(FeedDAO_Impl.java:255)
	at org.schabi.newpipe.local.feed.FeedDatabaseManager.upsertAll(FeedDatabaseManager.kt:91)
	at org.schabi.newpipe.local.feed.FeedDatabaseManager.upsertAll$default(FeedDatabaseManager.kt:78)
	at org.schabi.newpipe.local.feed.service.FeedLoadService$databaseConsumer$1$1.run(FeedLoadService.kt:323)
	at androidx.room.RoomDatabase.runInTransaction(RoomDatabase.java:556)
	at org.schabi.newpipe.local.feed.service.FeedLoadService$databaseConsumer$1.accept(FeedLoadService.kt:316)
	at org.schabi.newpipe.local.feed.service.FeedLoadService$databaseConsumer$1.accept(FeedLoadService.kt:65)
	at io.reactivex.rxjava3.internal.operators.flowable.FlowableDoOnEach$DoOnEachSubscriber.onNext(FlowableDoOnEach.java:86)
	at io.reactivex.rxjava3.internal.operators.flowable.FlowableBuffer$PublisherBufferExactSubscriber.onNext(FlowableBuffer.java:124)
	at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$ObserveOnSubscriber.runAsync(FlowableObserveOn.java:402)
	at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.run(FlowableObserveOn.java:176)
	at io.reactivex.rxjava3.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:65)
	at io.reactivex.rxjava3.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:56)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:301)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
	at java.lang.Thread.run(Thread.java:923)

---

[XiangRongLin]

Inside NewPipeDatabase add this method and use that to close the db. This way when getInstance is called a new instance is created.

    public static void close() {
        if (databaseInstance != null) {
            synchronized (NewPipeDatabase.class) {
                if (databaseInstance != null) {
                    databaseInstance.close();
                    databaseInstance = null;
                }
            }
        }
    }