Using a filename based on the hash of the contents means that the caching
algorithms for fdroidclient and browsers can safely cache the file forever
using the filename, since this guarantees that the contents will never
change for a given filename.
This does not cover screenshots, only icon.png, featureGraphic.png,
tvBanner.png, and promoGraphic.png.
fdroidserver#689
fdroid-website!453
699b3e4c69 got it wrong for targetSdkVersion.
Also, one confusing thing is that aapt outputs "sdkVersion: '3'" for
com.politedroid_3.apk but no "sdkVersion:" for no.min.target.sdk_987.apk.
F-Droid never really supported running on android-1 or android-2, so it
seems pointless to debug support for them.
pickle can serialize executable code, while JSON is only ever pure data.
The APK cache is only ever pure data, so no need for the security risks of
pickle. For example, if some malicious thing gets write access on the
`fdroid update` machine, it can write out a custom tmp/apkcache which would
then be executed. That is not possible with JSON.
This does just ignore any existing cache and rebuilds from scratch. That is
so we don't need to maintain pickle anywhere, and to ensure there are no
glitches from a conversion from pickle to JSON.
closes#163
Instead of just crashing, first try to use the versionName as written in the
build metadata, otherwise just let it be blank. A blank versionName will
cause fdroidclient < 1.3 to crash. Blank versionNames are not allowed in
the .txt metadata format, only .yml.
closes#477closes#478
closes fdroidclient#1416
closes fdroidclient#1417
closes fdroidclient#1418
fdroiddata!3061
