APK signature mismatch

[ema-pe]

Before creating an issue

1. Version: 0.43
2. Similar issue: Why is there a signature mismatch on a few popular apps lately?? #494
3. Done.

Expected behavior
WhatsApp application should be correctly updated.

Actual behavior
I can't update WhatsApp application because YalpStore says to me that the new APK's signature mismatch. I tried to install it anyway, but the system says that "There was a problem parsing the package". I tried also disabling delta updates, according do #494, but it didn't work.

Steps to reproduce

Your setup
Motorola Moto E 2015, LineageOS 14.1

[gohanko]

Reinstall WhatsApp. It can't update because the signature is not the same.

[yeriomin]

Hello.

After disabling delta updates, you could try deleting the apk and downloading it again in case there was a transmission problem.

If you did that already, try looking at your device's general logs. Android package installer (on your third screenshot) logs failure details/reasons.

How did you install WhatsApp initially? Did it come with the device?

[ema-pe]

Thanks @momo42, now WhatsApp is succesfully updated. I simply followed your istructions, disabling delta updates and deleting all apks from "Download" directory.

I also like your suggestions, I hope that @yeriomin will read them soon. This bug should be noticied to all users, because It is very common.

Anyway, I've installed WhatsApp initially with YalpStore.

Edit: deleting the old installed apk is a bad workaround, because all app's data will be lost.

[yeriomin]

@momo42 This issue is unrelated to delta updates, @ema-pe says they are disabled. Please create a new issue if you have something new to discuss.

Is there any way to delete the non-working deltas from internal memory?

Apks are deleted from internal storage automatically after some time.

Delta updates seem to be problematic.

This is why deltas are off by default.

Perhaps Yalp should automatically delete all previously downloaded apks from internal memory when switching deltas off!

Might be safer to just remove the option altogether.

The deltas problem is unlikely to be fixed any time soon, unfortunately. While the process itself works, it is impossible to know if deltas are applicable to the existing apk. Play Store has a way to know that, Yalp Store does not. It is possible to detect the signature mismatch and redownload automatically, but only after downloading and applying - there would be no point in having deltas as they are supposed to save traffic and time. The only proper way to work around this is to learn the checksum algo used by Play Store.

[gohanko]

I noticed that to, I unchecked delta updates and the apks install correctly.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[yeriomin]

@momo42 @ema-pe I solved this properly after all. There is a signature of the base apk (the one installed, the one being patched) returned with the download link. Previously I didn't know what kind of signature it was. It appears to be a sha1 signature encoded with base64 with URL and Filename Safe Alphabet with padding removed. This means it is possible to decide if delta is applicable to the installed apk before downloading anything.

The solution is in master.

[ema-pe]

@yeriomin thanks for fixing this. Good job!