Cannot link to Flann on Ubuntu 22.04

[galou]

Cannot link to Flann on Ubuntu 22.04

[cohnt]

Clearing the build cache solved the problem for me. Thanks!

[cohnt]

I also faced this issue, and can confirm that the fix you've suggested works on my system.

[kylc]

I am not able to reproduce using the minimal Docker setup below. Maybe you have an old FLANN version around being picked up by CMake?

docker run --mount type=bind,source="$(pwd)",target=/ompl --rm -it ubuntu:22.04

export DEBIAN_FRONTEND=noninteractive

apt-get update
apt-get -y install git liblz4-dev g++ cmake pkg-config libboost-serialization-dev libboost-filesystem-dev libboost-system-dev libboost-program-options-dev libboost-test-dev libeigen3-dev libode-dev wget libyaml-cpp-dev

git clone https://github.com/flann-lib/flann.git --branch 1.9.2
mkdir -p flann/build && cd flann/build
cmake -DBUILD_EXAMPLES=OFF .. && cmake --build . && cmake --install .

mkdir -p /ompl/build/Release && cd /ompl/build/Release/
cmake ../.. && cmake --build . --parallel

[cohnt]

I have flann 1.6.13 installed from pip.

[galou]

I have libflann-dev/jammy,now 1.9.1+dfsg-11 amd64 installed with apt.

[kylc]

I think these older FLANN versions are no longer supported after the recent commits. The README now links to Flann v1.9.2 and the CMake checks for at least the same.

[cohnt]

Since FLANN is an optional dependency, shouldn't OMPL be able to build if only an older version is available, by just not including it?

[kylc]

Yes, I think it should ignore older versions. I tried adding both of apt install libflann-dev (for 1.9.1) and pip install flann==1.6.13 to the Docker script above, and neither have any effect on the OMPL build.

Are you possibly building from an old build/ directory with a stale CMake cache?