Ninja can't find libsecp256k1.a for Android

[PeteClubSeven]

Hi, I followed the setup instructions provided and I seem to encounter a problem with the generated Ninja files. I'm trying to use the tap protocol for a Flutter plugin and consistently run into the same issue. The error I receive for the arm64-v8a and x86_64 abi's is as follows:

> Task :cktap_protocol:buildCMakeDebug[arm64-v8a] FAILED
C/C++: ninja: error: '/home/poops/Programming/Breez/cktap-protocol-flutter/contrib/tap-protocol/contrib/bitcoin-core/src/secp256k1/build/android/arm64-v8a/lib/libsecp256k1.a', needed by '/home/poops/Programming/Breez/cktap-protocol-flutter/example/build/cktap_protocol/intermediates/cxx/Debug/686p6u6f/obj/arm64-v8a/libcktap_protocol_plugin.so', missing and no known rule to make it

> Task :cktap_protocol:buildCMakeDebug[x86_64] FAILED
C/C++: ninja: error: '/home/poops/Programming/Breez/cktap-protocol-flutter/contrib/tap-protocol/contrib/bitcoin-core/src/secp256k1/build/android/x86_64/lib/libsecp256k1.a', needed by '/home/poops/Programming/Breez/cktap-protocol-flutter/example/build/cktap_protocol/intermediates/cxx/Debug/686p6u6f/obj/x86_64/libcktap_protocol_plugin.so', missing and no known rule to make it

Here's the configure step for arm64-v8a where you can see the libsecp256k1 build script does run:

> Task :cktap_protocol:configureCMakeDebug[arm64-v8a]
C/C++: debug|arm64-v8a :CMake Warning at /home/poops/.dev/android-studio/ndk/22.1.7171670/build/cmake/android.toolchain.cmake:449 (message):
C/C++: debug|arm64-v8a :  An old version of CMake is being used that cannot automatically detect
C/C++: debug|arm64-v8a :  compiler attributes.  Compiler identification is being bypassed.  Some
C/C++: debug|arm64-v8a :  values may be wrong or missing.  Update to CMake 3.19 or newer to use
C/C++: debug|arm64-v8a :  CMake's built-in compiler identification.
C/C++: debug|arm64-v8a :Call Stack (most recent call first):
C/C++: debug|arm64-v8a :  .cxx/Debug/686p6u6f/arm64-v8a/CMakeFiles/3.18.1-g262b901/CMakeSystem.cmake:6 (include)
C/C++: debug|arm64-v8a :  CMakeLists.txt:3 (project)
C/C++: debug|arm64-v8a :configure.ac:36: warning: The macro `AC_PROG_CC_C89' is obsolete.
C/C++: debug|arm64-v8a :configure.ac:36: You should run autoupdate.
C/C++: debug|arm64-v8a :./lib/autoconf/c.m4:1652: AC_PROG_CC_C89 is expanded from...
C/C++: debug|arm64-v8a :configure.ac:36: the top level
C/C++: debug|arm64-v8a :configure.ac:15: installing 'build-aux/compile'
C/C++: debug|arm64-v8a :configure.ac:9: installing 'build-aux/missing'
C/C++: debug|arm64-v8a :Makefile.am: installing 'build-aux/depcomp'
C/C++: debug|arm64-v8a :configure: WARNING: using cross tools not prefixed with host triplet
C/C++: debug|arm64-v8a :configure: WARNING: using cross tools not prefixed with host triplet
C/C++: debug|arm64-v8a :configure: WARNING: using cross tools not prefixed with host triplet
C/C++: debug|arm64-v8a :configure: WARNING: using cross tools not prefixed with host triplet

Here's the CMakeLists.txt for my project:

cmake_minimum_required(VERSION 3.16)

project(cktap_protocol_plugin)

add_library(cktap_protocol_plugin

        # Sets the library as a shared library.
        SHARED

        # Provides a relative path to your source file(s).
        src/main/cpp/test.cpp)

execute_process(COMMAND "${CMAKE_SOURCE_DIR}/cmake_requirements.sh" "${CMAKE_ANDROID_NDK}")

add_subdirectory("${CMAKE_SOURCE_DIR}/../contrib/tap-protocol" "${CMAKE_SOURCE_DIR}/../contrib/tap-protocol/build")
target_link_libraries("${PROJECT_NAME}" PUBLIC  tap-protocol)

And the script being called by my CMakeLists.txt:

#!/bin/bash

scriptDir=`dirname '$0'`
echo $0
echo $1

pushd "$scriptDir/../contrib/tap-protocol"
ANDROID_NDK="$1" tools/build_android.sh
popd

Proof that the files exists:

poops@ramuh ~/P/B/c/android (develop)> find ../ -type f -name libsecp256k1.a -exec readlink -f {} \;
/home/poops/Programming/Breez/cktap-protocol-flutter/contrib/tap-protocol/contrib/bitcoin-core/src/secp256k1/build/android/arm64-v8a/lib64/libsecp256k1.a
/home/poops/Programming/Breez/cktap-protocol-flutter/contrib/tap-protocol/contrib/bitcoin-core/src/secp256k1/build/android/armeabi-v7a/lib/libsecp256k1.a
/home/poops/Programming/Breez/cktap-protocol-flutter/contrib/tap-protocol/contrib/bitcoin-core/src/secp256k1/build/android/x86-64/lib64/libsecp256k1.a
/home/poops/Programming/Breez/cktap-protocol-flutter/contrib/tap-protocol/contrib/bitcoin-core/src/secp256k1/build/android/x86/lib/libsecp256k1.a

[PeteClubSeven]

Oh wow, sorry I see the problem! I've been looking at this for a while and compared the paths of the 32-bit libraries so I thought the files were just being ignored. It seems the script outputs the 64-bit libraries in a lib64 folder but Ninja looks for a lib folder. I'll fix the issue a submit a pull request.