Crash when reading old cache

[mvnowak]

Unfortunately this bug seems to keep reappearing😄 The clean install of 5.1.4 works perfectly fine (also thanks for crediting me in the release notes) but when updating from 4.0.1 with an existing save file it crashes again.

However this time its reproducible in the Emulator, so maybe that helps in getting rid of the bug.

Steps to reproduce:

1. Check out the revision of the repository where version was updated to 4.0.1
2. Build and clean install this version on the emulator
3. Open the app and create an entry
4. Check out the current master branch (5.1.4) and update the app on the emulator by building and running again

I appended the full crash log at the end, but the only relevant lines are

Caused by: java.io.InvalidClassException: com.katiearose.sobriety.Addiction;
at com.katiearose.sobriety.CacheHandler.readCache(CacheHandler.kt:17)
at com.katiearose.sobriety.Main.onCreate(Main.kt:61)

I don't really get why it crashes, because there is try catch blocks everywhere that should have caught that exception.
Mabye its worth considering to use a different way of storage, since these FileOutPutStreams etc. are a bit tricky to debug. Since the data is very simple, you could use Android's Shared Preferences, and save the list as a serialized string in a single key value pair there. Or if you want to debug the current system, here is the full crash log:

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.katiearose.sobriety, PID: 21703
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.katiearose.sobriety/com.katiearose.sobriety.Main}: java.io.InvalidClassException: com.katiearose.sobriety.Addiction; local class incompatible: stream classdesc serialVersionUID = -8477717136644775154, local class serialVersionUID = 7971970991809636397
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3635)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3792)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2210)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.app.ActivityThread.main(ActivityThread.java:7839)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
Caused by: java.io.InvalidClassException: com.katiearose.sobriety.Addiction; local class incompatible: stream classdesc serialVersionUID = -8477717136644775154, local class serialVersionUID = 7971970991809636397
at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:624)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1713)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1594)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1872)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1412)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:427)
at java.util.ArrayList.readObject(ArrayList.java:791)
at java.lang.reflect.Method.invoke(Native Method)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1066)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2013)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1899)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1412)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:427)
at com.katiearose.sobriety.CacheHandler.readCache(CacheHandler.kt:17)
at com.katiearose.sobriety.Main.onCreate(Main.kt:61)
at android.app.Activity.performCreate(Activity.java:8051)
at android.app.Activity.performCreate(Activity.java:8031)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1329)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3608)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3792) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2210) 
at android.os.Handler.dispatchMessage(Handler.java:106) 
at android.os.Looper.loopOnce(Looper.java:201) 
at android.os.Looper.loop(Looper.java:288) 
at android.app.ActivityThread.main(ActivityThread.java:7839) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003) 

[KiARC]

Oh this one is my bad actually because Addiction was modified in the new version and I need to update the readLegacyCache function to use the AddictionOld class instead iirc. Maybe I already did and am just tired since it's the morning but I'm fairly sure that's what's wrong.

[KiARC]

Wait... No that isn't it, that class was scrapped

[KiARC]

Ahhhh that is it, and I made a mistake scrapping it. Essentially, the 5.1.4 Addiction class isn't the same as the 4.0.1 Addiction class, so I need a legacy one in there to facilitate cache reads. On top of that, readLegacyCache() is still set up to read 3.x.x caches 🤦‍♀️

[KiARC]

So yeah I'll fix that later today

[KiARC]

Ah. Bigger issue. Because of how JVM serialization works, you can't rename a class and still deserialize things properly, so I need to see what I can do, but it may be that 4.x.x caches will not work with 5.x.x and I'll need to start designing a more long-term-stable cache format.

[KiARC]

Technically solved, and the new cache format is WIP now.