Provide module information (JPMS)

[tobiasdiez]

Is your feature request related to a problem? Please describe.
Currently it very hard to use the apollo library in a modularized application. For example, there are split package issues between apollo-runtime and apollo-api. I'll describe these problems further below in more detail (along with a workaround).

Describe the solution you'd like
The usage would be way easier if the apollo library would be modularized, or at least could provide module-info.class.

Problems & Workarounds

1. Adding apollo-runtime leads to split package problems like the following

error: module java.xml.bind reads package com.apollographql.apollo from both apollo.api.jvm and apollo.runtime
error: module java.xml.bind reads package com.apollographql.apollo.exception from both apollo.api.jvm and apollo.runtime

Fixed by excluding the sub-dependencyies

    implementation ("com.apollographql.apollo:apollo-runtime:2.5.8"){
        exclude module: "apollo-api"
        exclude module: "apollo-normalized-cache"
    }

and then downloading the apollo-api-jvm.x.jar file manually, and merging with apollo-runtime by modularity.patchModule("apollo.runtime", "apollo-api-jvm-2.5.8.jar") using the gradle plugin org.javamodularity.moduleplugin.

2. Apollo accesses internal apis
   Fixed by adding add-exports for

                'apollo.runtime/com.apollographql.apollo.ap = org.your_module',
                'apollo.runtime/com.apollographql.apollo.api.internal = org.your_module'

3. Access problems

error: cannot access Function1
        final GetUserDocumentRaw getUserDocumentRaw = reader.readObject($responseFields[0], new ResponseReader.ObjectReader<GetUserDocumentRaw>() {
                                                            ^
  class file for kotlin.jvm.functions.Function1 not found

Fixed by adding requires kotlin.stdlib; to one's module-info file. (This is probably something one still has to to even with a proper module description from apollo's side; but it should be mentioned in the documentation.)

[martinbonnin]

@tobiasdiez I ended up setting up Apollo Android 3 as automatic modules in #3558. Going the full module-info.class would be nice but that'd come with a lot of complexity. We would basically need to publish 2 versions of the artifacts. One with compiled with Java 8 and the other with Java9+

From the tests, automatic modules are working quite well but the tests are a simple project. If you have a more complex project to try it with, I'd be super curious to hear your thoughts.

[tobiasdiez]

Thanks a lot, we will try it soon and then report back if it works.

[Siedlerchr]

I can confirm that the latest 3.0.0-beta04 now works without any hacks in a JPMS project with java 16:
JabRef/jabref@bc04a98

Now we need to adapt the code to the new syntax

[martinbonnin]

Closing. Please leave a comment if you want me to reopen.

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