Moshi: Add @Nullable @NonNull throught the library

[PaulWoitaschek]

It would be great to have the whole api annotated with @Nullable and @NonNull.
Also it would play way better together with kotlin. For example the JsonAdapter.Factory:

    /**
     * Attempts to create an adapter for {@code type} annotated with {@code annotations}. This
     * returns the adapter if one was created, or null if this factory isn't capable of creating
     * such an adapter.
     *
     * <p>Implementations may use to {@link Moshi#adapter} to compose adapters of other types, or
     * {@link Moshi#nextAdapter} to delegate to the underlying adapter of the same type.
     */
    JsonAdapter<?> create(Type type, Set<? extends Annotation> annotations, Moshi moshi);

Currently one really has to read the documentation.
What kotlin does by default is:

override fun create(type: Type?, annotations: MutableSet<out Annotation>?, moshi: Moshi?): JsonAdapter<*> 

where it should be

override fun create(type: Type, annotations: MutableSet<out Annotation>, moshi: Moshi): JsonAdapter<*>?

[NightlyNexus]

Maybe there should be one big issue on one project somewhere to communicate plans?
kind of tracking this here: https://github.com/square/retrofit/issues/624#issuecomment-265429436

[PaulWoitaschek]

Something else: Validation of null input is not done Properly. I just received a bit weird crash because I passed null to JsonAdapter.fromJson(String) and the Buffer called string.length() in writeUtf8 and caused a NPE. It would be handy if you could check the arguments and fail immediately rather than relying on the implementation to crash.

[swankjesse]

Implemented. https://github.com/square/moshi/pull/297

[PaulWoitaschek]

If I understand correctly the String is still not annotated and will crash in Okios Buffer?

[joshfriend]

package-info.java is annotated with @ParametersAreNonnullByDefault but Kotlin doesn't support that yet.

[PaulWoitaschek]

Annotated or not, it's still crashing because a dependent is crashing.

[swankjesse]

If this is blocking you, please vote this up: https://youtrack.jetbrains.com/oauth?state=%2Fissue%2FKT-10942

[3flex]

package-info.java is annotated with @ParametersAreNonnullByDefault but Kotlin doesn't support that yet.

Should be fixed in Kotlin 1.1.4. Support for the annotations can be enabled by passing the -Xjsr305-annotations=enable command line option to the compiler. Info in the release announcement.

[swankjesse]

No further action for Moshi on this.