How to use audioplayers_linux_plugin.so in a Snap build?

[munch-software]

Error Message

When building a Snap from my Flutter project, I encounter the following error on run:

Flutter Snap Build Error: g_type_plugin_use Assertion Failed

Debugging Output

Thread 1 "munch_pos" received signal SIGABRT, Aborted.
0x000078c8e349f00b in raise () from target:/lib/x86_64-linux-gnu/libc.so.6
(gdb) bt full
#0  0x000078c8e349f00b in raise () from target:/lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#1  0x000078c8e347e859 in abort () from target:/lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#2  0x000078c8e589cc51 in g_assertion_message[cold] () from target:/snap/example/x1/lib/libaudioplayers_linux_plugin.so
No symbol table info available.
#3  0x000078c8e591876f in g_assertion_message_expr () from target:/snap/example/x1/lib/libaudioplayers_linux_plugin.so
No symbol table info available.
#4  0x000078c8e58c8926 in g_type_class_ref () from target:/snap/example/x1/lib/libaudioplayers_linux_plugin.so
No symbol table info available.
#5  0x000078c8e58abdd8 in g_object_new_with_properties () from target:/snap/example/x1/lib/libaudioplayers_linux_plugin.so
No symbol table info available.
#6  0x000078c8e58ac891 in g_object_new () from target:/snap/example/x1/lib/libaudioplayers_linux_plugin.so
............
#40 0x000078c8e58c4293 in g_signal_emit () from target:/snap/example/x1/lib/libaudioplayers_linux_plugin.so
No symbol table info available.
#41 0x0000000000402982 in my_application_local_command_line(_GApplication*, char***, int*) ()
No symbol table info available.
#42 0x000078c8e3c37b92 in g_application_run () from target:/snap/example/x1/gnome-platform/usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
No symbol table info available.
#43 0x000000000040246e in main () 

---

Possible Cause

I suspect this is due to a mismatch of GTK libraries. When checking linked libraries, I see:

ldd /snap/example/x1/lib/libaudioplayers_linux_plugin.so | grep -E "gtk|gobject|glib"

        libflutter_linux_gtk.so => not found
        libgtk-3.so.0 => /lib/x86_64-linux-gnu/libgtk-3.so.0 (0x00007137c8200000)
        libcairo-gobject.so.2 => /lib/x86_64-linux-gnu/libcairo-gobject.so.2 (0x00007137c89dd000)
        libgobject-2.0.so.0 => /lib/x86_64-linux-gnu/libgobject-2.0.so.0 (0x00007137c7be8000)
        libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007137c7a9f000)

Attempts to Fix

So libaudioplayers_linux_plugin.so uses system packages instead of the gnome-platform.
Not sure why libflutter shows Not Found since it is available: /snap/example/x1/lib/libflutter_linux_gtk.so

• Tried different Ubuntu core versions —same result.
• Tried using with the flutter plugin and without.
• Also tried using core:18 with snapcraft 7, however got a different error, relating to: CMake build error #1197
• Attempted to force the Snap to only use the gnome-platform by removing duplicated system packages —same result.

Snapcraft yaml:

name: flutter-app
version: '1.0'
summary: abc
description: |
  abc
base: core20
confinement: devmode
grade: stable

apps:
  flutter-app:
    extensions: [gnome-3-38]
    command: flutter_app
    plugs:
      - network
      - audio-playback

parts:
  flutter-app:
    source: .
    plugin: nil
    override-build: |
      rm -rf $SNAPCRAFT_PART_SRC/build
      #snapcraftctl build
      git clone --depth 1 --branch 3.24.3 https://github.com/flutter/flutter.git $SNAPCRAFT_PART_INSTALL/flutter
      export PATH="$SNAPCRAFT_PART_INSTALL/flutter/bin:$PATH"
      flutter config --enable-linux-desktop
      flutter doctor
      flutter clean
      flutter pub get
      flutter build linux --dart-define-from-file=devops/munch/cfd.qa.env
      install -D build/linux/x64/release/bundle/munch_pos $SNAPCRAFT_PART_INSTALL/munch_pos
      cp -r build/linux/x64/release/bundle/lib/* $SNAPCRAFT_PART_INSTALL/lib/
      cp -r build/linux/x64/release/bundle/data $SNAPCRAFT_PART_INSTALL/data/
    
build-packages:
      - git
      - unzip
      - clang
      - curl
      - lld
      - libc6-dev
      - cmake
      - ninja-build
      - pkg-config
      - liblzma-dev
      - libgstreamer1.0-dev
      - libgstreamer-plugins-base1.0-dev
    
stage-packages:
      - gstreamer1.0-plugins-good
      - gstreamer1.0-plugins-bad
      - gstreamer1.0-tools
    
organize:
      usr/lib/x86_64-linux-gnu/libpango*: gnome-platform/usr/lib/x86_64-linux-gnu/
  
cleanup:
    after: [ flutter-app ]
    plugin: nil
    build-snaps:
      - gnome-3-38-2004
    override-prime: |
      set -eux
      # Remove duplicate libraries that exist in the GNOME runtime
      rm -rf $SNAPCRAFT_PRIME/usr/lib/x86_64-linux-gnu/libpango*
      rm -rf $SNAPCRAFT_PRIME/usr/lib/x86_64-linux-gnu/libgtk*