Pillow vs pip

Not sure if this is a bug in OCR-D, maybe someone with more pip kungfu can enlighten us?

#!/bin/sh                                                                                                               
cd `mktemp -d`                                                                                                          
                                                                                                                        
virtualenv -p /usr/bin/python3 venv                                                                                     
. venv/bin/activate                                                                                                     
                                                                                                                        
pip install ocrd ocrd_utils | grep -i pillow       

yields:

% sh pillow-error.sh
Already using interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /tmp/tmp.XKB4hlZZVe/venv/bin/python3
Also creating executable in /tmp/tmp.XKB4hlZZVe/venv/bin/python
Installing setuptools, pip, wheel...done.
Collecting Pillow>=5.3.0 (from ocrd)
  Using cached https://files.pythonhosted.org/packages/a4/da/2bd281c875686230eabc13d20ab590ea617563b0e746abfb0698c4d5b645/Pillow-6.1.0-cp37-cp37m-manylinux1_x86_64.whl
ERROR: ocrd-utils 1.0.0b19 has requirement Pillow==5.4.1, but you'll have pillow 6.1.0 which is incompatible.
Installing collected packages: lxml, Pillow, bagit, urllib3, certifi, chardet, idna, requests, numpy, opencv-python, MarkupSafe, Jinja2, click, Werkzeug, itsdangerous, Flask, pyyaml, wrapt, Deprecated, six, pyrsistent, attrs, jsonschema, bagit-profile, ocrd, ocrd-utils
Successfully installed Deprecated-1.2.0 Flask-1.1.1 Jinja2-2.10.1 MarkupSafe-1.1.1 Pillow-6.1.0 Werkzeug-0.16.0 attrs-19.1.0 bagit-1.7.0 bagit-profile-1.3.0 certifi-2019.9.11 chardet-3.0.4 click-7.0 idna-2.8 itsdangerous-1.1.0 jsonschema-3.0.2 lxml-4.4.1 numpy-1.17.2 ocrd-0.15.2 ocrd-utils-1.0.0b19 opencv-python-4.1.1.26 pyrsistent-0.15.4 pyyaml-5.1.2 requests-2.22.0 six-1.12.0 urllib3-1.25.6 wrapt-1.11.2

So what pip does here is

1. Installing Pillow 6.1.0 because of ocrd’s dependency on Pillow>=5.3.0
2. Complaining about Pillow 6.1.0 because of ocrd-utils’ (!) dependency on Pillow 5.4.1

😖

Motivation for this bug report is that i get a red error message on every install:

ERROR: ocrd-utils 1.0.0b19 has requirement Pillow==5.4.1, but you'll have pillow 6.1.0 which is incompatible.

[bertsky]

@mikegerber The problem does affect Pillow 6.1, see here.

[kba]

Please have a look at #336