Python Interop on a (32-bit, ARM) Raspberry Pi Zero?

Thanks for this project! I enjoyed the talk from this year's Conj and it made me want to dive right in.

My use case is somewhat unique, I think: I'm trying to use Python to drive some hardware I have soldered to the GPIO pins on a Raspberry Pi Zero. The Pi is a 32-bit ARM processor, and Python works great on it... but Python interop has been giving me a bit of trouble.

Here's what we're working with:

 $ ldconfig -p | grep python
        libpython3.7m.so.1.0 (libc6,hard-float) => /usr/lib/arm-linux-gnueabihf/libpython3.7m.so.1.0
        libpython3.7m.so (libc6,hard-float) => /usr/lib/arm-linux-gnueabihf/libpython3.7m.so
        libpython2.7.so.1.0 (libc6,hard-float) => /usr/lib/arm-linux-gnueabihf/libpython2.7.so.1.0
        libpython2.7.so (libc6,hard-float) => /usr/lib/arm-linux-gnueabihf/libpython2.7.so

and Java:

$ java -version
openjdk version "1.8.0_152"
OpenJDK Runtime Environment (Zulu Embedded 8.25.0.76-linux-aarch32hf) (build 1.8.0_152-b76)
OpenJDK Client VM (Zulu Embedded 8.25.0.76-linux-aarch32hf) (build 25.152-b76, mixed mode, Evaluation)

I'm using Python 3.7 to drive the hardware, and Python itself runs fine.
Likewise, I can run Clojure (both JARs and Clojure in the REPL) without any issue.
But when I try to run Python from within Clojure via the REPL, here's what happens:

=> (require '[libpython-clj.python :as py])
nil
=> (py/initialize!)
Jan 09, 2020 3:05:16 AM clojure.tools.logging$eval1906$fn__1909 invoke
INFO: Executing python initialize!
Jan 09, 2020 3:05:17 AM clojure.tools.logging$eval1906$fn__1909 invoke
INFO: Startup info detected: {:python-home "/usr", :lib-version "3.7", :libname "python3.7m", :java-library-path-addendum "/usr/lib"}
Jan 09, 2020 3:05:17 AM clojure.tools.logging$eval1906$fn__1909 invoke
INFO: Reference thread starting
Jan 09, 2020 3:05:18 AM clojure.tools.logging$eval1906$fn__1909 invoke
INFO: Library python3.7m found at [:system "python3.7m"]
Execution error (IllegalArgumentException) at libpython-clj.jna.base/eval22533$fn$G (base.clj:20).
No implementation of method: :->py-object-ptr of protocol: #'libpython-clj.jna.base/PToPyObjectPtr found for class: nil

The error repeats itself if you try any other commands:

=> (py/run-simple-string "print('Hello')")
Execution error (IllegalArgumentException) at libpython-clj.jna.base/eval22533$fn$G (base.clj:20).
No implementation of method: :->py-object-ptr of protocol: #'libpython-clj.jna.base/PToPyObjectPtr found for class: nil

I started the repl using lein repl in a new project root.
The project was scaffolded with the lein new app command.

Do you see anything off the top of your head that may be the root cause of these issues?

My gut tells me it's one of three things:

1. The 32-bit ARM processor, and everything that goes along with that
2. The Zulu Embedded Java 8 JDK
3. Something dumb that I haven't noticed yet.

Any thoughts as to why this is happening, or is there any more information I could provide?

Really appreciate your time. Thank you!

記載されている32ビットARM Raspberry Pi環境で、libpython-clj.python/initialize! と py/run-simple-string を使って Clojure REPL から失敗を再現します。libpython-clj/jna/base.clj:20 から開始し、PToPyObjectPtr プロトコルによって報告された nil 値を追跡します。プラットフォーム、Java ランタイム、プロジェクト設定のいずれが失敗の原因かを特定し、検証済みの解決策を記録できれば完了です。