selection via OCRD_MODULES fails due to dependent modules

[joschrew]

I tried to install ocrd_all with the setup-guide: https://ocr-d.de/en/setup:

make all OCRD_MODULES="core ocrd_tesserocr ocrd_cis"

and got following error running the mentioned command:

Successfully installed numpy-1.24.3 shapely-2.0.1
make[1]: Leaving directory '/home/cloud/repos/ocrd_all/core' 
. /home/cloud/repos/ocrd_all/venv/bin/activate && cd tesserocr && sem -q --will-cite --fg --id ocrd_all_pipvenv pip insta
ll  .
ERROR: Directory '.' is not installable. Neither 'setup.py' nor 'pyproject.toml' found.
make: *** [Makefile:671: /home/cloud/repos/ocrd_all/venv/share/tesserocr] Error 1

Seems the problem is that ocrd_tesserocr needs tesserocr to be installed. The installation of tesserocr is triggered but the sources are not fetched and that leads to the error. Running make all OCRD_MODULES="core ocrd_tesserocr ocrd_cis tesseract tesserocr" resolves the problem but maybe it would be good to change the makefile to be able to fetch the needed sources itself.

[bertsky]

Except for core (which is needed everywhere and can be seen as a special case) and tesseract/tesserocr, we have no dependencies between modules. In the latter case, we have some special rules which should switch over to the PPA installation of Tesseract if it is not selected as a module. So AFAICS the actual issue here is more specific: for some reason, these rules for tesserocr do not work anymore.

[bertsky]

Looking closer, we have 3 places where we try to turn some pip dependency into an explicit target via $(SHARE)/%:

• numpy → do we still need this? It gets pulled by core already, and many modules depend on it – all via pip. IIRC the initial reason was that OpenCV build used to have it as a build-time dependency
• opencv-python → only need on some platforms without prebuilt versions on PyPI; installation via source module (custom rules) is enforced by making core depend on it explicitly (so it gets built before anything else)
• tesserocr → there used to be a time when no usable prebuilt version were available on PyPI (that would interoperate with recent Tesseract), and this may happen again in the future; for that we included it as a submodule; but when you do not activate it (via git submodule init or OCRD_MODULES), this should just install via pip. Apparently, the latter is not the case (anymore?).

[bertsky]

BTW, opencv-python build is broken at the moment.

[bertsky]

has been fixed by #362