PHLEX_PLUGIN_PATH must include phlex libraries

[Charlotte-Knight]

I tried running the examples included in this repository. I ran into issues installing via spack, which are documented in DUNE/dune_spack#37 and then moved on to installing via conda/micromamba.

When creating an environment with the following options:

micromamba env create -n phlex-final -c conda-forge gcc=15 gxx=15 cmake libboost-devel tbb-devel phlex -y

I was able to run make and build the phlex-examples.

However, I ran into this error

(phlex-final) [mdk16@lx04 phlex-examples]$ phlex -c test-cpp-workflow.jsonnet
Using configuration file: test-cpp-workflow.jsonnet
[2026-08-12 11:32:48.001] [info] Number of worker threads: 72
[2026-08-12 11:32:48.006] [info]
[2026-08-12 11:32:48.006] [info] CPU time: 0.00281s  Real time: 0.00493s  CPU efficiency:  57.03%
[2026-08-12 11:32:48.006] [info] Max. RSS: 19.312 MB
Could not locate library with specification 'form_module' in any directories on PHLEX_PLUGIN_PATH.

which I managed to fix by including /home/hep/mdk16/.local/share/mamba/envs/phlex-final/lib/ in my PHLEX_PLUGIN_PATH. I do not know if this is a necessary addition when installing Phlex via Spack, but it was needed for the conda route.

Therefore, the instructions may need updating to warn users of this. I guess that'll depend how spack-specific the instructions are designed to be. I can update the issue here if I get manage to get the installation via spack working, and then I can confirm if it is an issue regardless of installation route.

[coderabbitai]

⚠️ Possible Duplicate Issue(s)

• Some problems with paths for C++ in README #2

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[olantwin]

Hi @Charlotte-Knight, responding since I maintain the conda-forge package. In this case, it's probably something we should set as part of the activation script in the phlex package (FORM is part of phlex, at least for now).