[shared_preferences] Fix Android Java version issue

[stuartmorgan-g]

Sets the compile version to 1.8, which is required by some features added in the switch to Pigeon. This is a standard part of the current Android plugin template, but this plugin predates that template change.

Fixes flutter/flutter#124839

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[stuartmorgan-g]

@reidbaker I'm assuming the reason we don't see this in CI is that with a new enough version of everything (Java? Gradle? AGP?) it won't try to compile with 1.7 regardless?

I'm going to do a sweep of all of our plugins to add this anywhere else we don't have it, but I wanted to do this one ASAP to get the fix out since it's breaking a bunch of people (although it will stop breaking new people now that I've retracted 2.1.1).

[reidbaker]

@reidbaker I'm assuming the reason we don't see this in CI is that with a new enough version of everything (Java? Gradle? AGP?) it won't try to compile with 1.7 regardless?

I'm going to do a sweep of all of our plugins to add this anywhere else we don't have it, but I wanted to do this one ASAP to get the fix out since it's breaking a bunch of people (although it will stop breaking new people now that I've retracted 2.1.1).

I just checked the compatibility for all the items I have recently researched.
AGP: https://developer.android.com/build/releases/gradle-plugin
Gradle: https://docs.gradle.org/current/userguide/compatibility.html

This is the only quote that stands out "Java 6 and 7 can still be used for compilation, but are deprecated for use with testing. Testing with Java 6 and 7 will not be supported in Gradle 9.0."

[stuartmorgan-g]

I looked around a bit more and found this, which says that the default value is the toolchain's value (which we don't set), and the default toolchain is the "build JVM toolchain".

[reidbaker]

I looked around a bit more and found this, which says that the default value is the toolchain's value (which we don't set), and the default toolchain is the "build JVM toolchain".

Based on my reading of that link we should be setting toolchain and not source compatibility.

[stuartmorgan-g]

Based on my reading of that link we should be setting toolchain and not source compatibility.

I noticed that too, but I'm not clear on what other effects that has (if any). The flutter plugin template, and most of our plugins, currently use sourceCompatibility, so we know it works and is tested, so I went with that as the incremental solution from "definitely wrong" to "on par with the rest of our working code".

It seemed like toolchain was someting we should look into longer term as a potential template change and repo-wide update. I have a note to file it, and will do that on Monday (unless you want to do it first).

[reidbaker]

Based on my reading of that link we should be setting toolchain and not source compatibility.

I noticed that too, but I'm not clear on what other effects that has (if any). The flutter plugin template, and most of our plugins, currently use sourceCompatibility, so we know it works and is tested, so I went with that as the incremental solution from "definitely wrong" to "on par with the rest of our working code".

It seemed like toolchain was someting we should look into longer term as a potential template change and repo-wide update. I have a note to file it, and will do that on Monday (unless you want to do it first).

That makes sense to me.