Try to preserve the app cache on uninstall.

[dellis1972]

Context #9259

Due to various reasons adb may not be able to preserve the app cache on uninstall. To work around this we have to use the -k flag to uninstall the app when using the cmd package uninstall call. This will keep the app data and cache on the device.

However this might also fail. So in that case we need to completely uninstall the app and then install it again.

[grendello]

Can we make -k optional (used by default)? Removing the cache is important in performance testing, but
also when one needs to test the application to see how it works from scratch.

[dellis1972]

Can we make -k optional (used by default)? Removing the cache is important in performance testing, but also when one needs to test the application to see how it works from scratch.

the -k tries to preserve the cache if it can. If someone uninstalls the app manually on the phone (or emulator) it will delete the cache .

[dellis1972]

Can we make -k optional (used by default)? Removing the cache is important in performance testing, but also when one needs to test the application to see how it works from scratch.

note that the very first call to adb uninstall -k <package> has the -k in it.
This only gets used when you are using aab btw. So if the performance tests are using apk this code is completely skipped.

[jonathanpeppers]

I was looking what "fast deployment" does for this in Debug mode, and I can only find the pm command:

• https://dev.azure.com/devdiv/DevDiv/_git/android-platform-support?path=/src/Mono.AndroidTools/Internal/AdbCommand.cs&version=GBmain&_a=contents&line=728&lineStyle=plain&lineEnd=728&lineStartColumn=15&lineEndColumn=33

Should we only use the pm command here instead of trying two commands? Just to make Debug & Release consistent?

We can also update this target, which is maybe not used:

android/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

Lines 3017 to 3030 in 747041d

	<Target Name="_Uninstall">
	<AndroidAdb
	ToolExe="$(AdbToolExe)"
	ToolPath="$(AdbToolPath)"
	AdbTarget="$(AdbTarget)"
	Command="uninstall"
	Arguments="$(_AndroidPackage)"
	/>
	</Target>
	<Target Name="Uninstall"
	Condition="'$(AndroidApplication)'!='' And $(AndroidApplication)"
	DependsOnTargets="$(UninstallDependsOnTargets)">
	</Target>

[dellis1972]

I was looking what "fast deployment" does for this in Debug mode, and I can only find the pm command:

• https://dev.azure.com/devdiv/DevDiv/_git/android-platform-support?path=/src/Mono.AndroidTools/Internal/AdbCommand.cs&version=GBmain&_a=contents&line=728&lineStyle=plain&lineEnd=728&lineStartColumn=15&lineEndColumn=33

Should we only use the pm command here instead of trying two commands? Just to make Debug & Release consistent?

We can also update this target, which is maybe not used:

android/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

Lines 3017 to 3030 in 747041d

	<Target Name="_Uninstall">
	<AndroidAdb
	ToolExe="$(AdbToolExe)"
	ToolPath="$(AdbToolPath)"
	AdbTarget="$(AdbTarget)"
	Command="uninstall"
	Arguments="$(_AndroidPackage)"
	/>
	</Target>
	<Target Name="Uninstall"
	Condition="'$(AndroidApplication)'!='' And $(AndroidApplication)"
	DependsOnTargets="$(UninstallDependsOnTargets)">
	</Target>

So just use the pm and remove the previous call? I'm ok with that, I'll update this PR.

[jonathanpeppers]

You might review what android-platform-support does in case I missed it, to just check that it always uses pm uninstall.