Bug#935887: python3-mapproxy: Change default template_dir and fix capabilities for Python >= 3.6.7

[Sebastiaan Couwenberg]

Control: tags -1 - moreinfo
Control: severity -1 important

I've installed mapproxy on a test server with stretch, it contains the
symlinks as well:

 # find /usr/lib/python2.7/dist-packages/mapproxy/ -type l -exec ls -l {} \;
 lrwxrwxrwx 1 root root 73 Jan  7  2018
/usr/lib/python2.7/dist-packages/mapproxy/test/system/fixture/cache_data
-> ../../../../../../../share/python-mapproxy/test/system/fixture/cache_data
 lrwxrwxrwx 1 root root 49 Jan  7  2018
/usr/lib/python2.7/dist-packages/mapproxy/test/schemas ->
../../../../../share/python-mapproxy/test/schemas
 lrwxrwxrwx 1 root root 54 Jan  7  2018
/usr/lib/python2.7/dist-packages/mapproxy/service/templates ->
../../../../../share/python-mapproxy/service/templates
 lrwxrwxrwx 1 root root 60 Jan  7  2018
/usr/lib/python2.7/dist-packages/mapproxy/image/fonts/DejaVuSans.ttf ->
../../../../../../share/fonts/truetype/dejavu/DejaVuSans.ttf
 lrwxrwxrwx 1 root root 64 Jan  7  2018
/usr/lib/python2.7/dist-packages/mapproxy/image/fonts/DejaVuSansMono.ttf
-> ../../../../../../share/fonts/truetype/dejavu/DejaVuSansMono.ttf

It as successfully serves the demo with your mapproxy.yaml, both the PNG
& Capabilities document.

After the upgrade to buster, the demo still works when using the default
python2.7 packages, python-mapproxy also contains the symlinks:

 # find /usr/lib/python2.7/dist-packages/mapproxy/ -type l -exec ls -l {} \;
 lrwxrwxrwx 1 root root 73 Jan  7  2018
/usr/lib/python2.7/dist-packages/mapproxy/test/system/fixture/cache_data
-> ../../../../../../../share/python-mapproxy/test/system/fixture/cache_data
 lrwxrwxrwx 1 root root 49 Jan  7  2018
/usr/lib/python2.7/dist-packages/mapproxy/test/schemas ->
../../../../../share/python-mapproxy/test/schemas
 lrwxrwxrwx 1 root root 54 Jan  7  2018
/usr/lib/python2.7/dist-packages/mapproxy/service/templates ->
../../../../../share/python-mapproxy/service/templates
 lrwxrwxrwx 1 root root 60 Jul 31  2018
/usr/lib/python2.7/dist-packages/mapproxy/image/fonts/DejaVuSans.ttf ->
../../../../../../share/fonts/truetype/dejavu/DejaVuSans.ttf
 lrwxrwxrwx 1 root root 64 Jul 31  2018
/usr/lib/python2.7/dist-packages/mapproxy/image/fonts/DejaVuSansMono.ttf
-> ../../../../../../share/fonts/truetype/dejavu/DejaVuSansMono.ttf

python3-mapproxy indeed does not:

 # find /usr/lib/python3/dist-packages/mapproxy/ -type l -exec ls -l {} \;
 lrwxrwxrwx 1 root root 60 Jul 31  2018
/usr/lib/python3/dist-packages/mapproxy/image/fonts/DejaVuSans.ttf ->
../../../../../../share/fonts/truetype/dejavu/DejaVuSans.ttf
 lrwxrwxrwx 1 root root 64 Jul 31  2018
/usr/lib/python3/dist-packages/mapproxy/image/fonts/DejaVuSansMono.ttf
-> ../../../../../../share/fonts/truetype/dejavu/DejaVuSansMono.ttf

And hence also cannot run the demo successfully.

I've downgraded the severity of this issue since the defaults still work.

While mapproxy 1.11.1 doesn't contain any related changes, it does
successfully serve the PNG with Python 3 on bullseye (testing). It fails
with an internal error for the Capabilities document:

 TypeError: Extra position arguments: True at line 169 column 3 in file
/usr/lib/python3/dist-packages/mapproxy/service/templates/wms111capabilities.xml

I'll fix this first in unstable by cherry-picking the commit.

Do you really need to run mapproxy with Python 3 on buster?

If not, we can leave the package as it, just use python-mapproxy on
buster (which is installed as a dependency of the mapproxy package).

Otherwise I'll need to prepare a stable update with the commit for the
TypeError and find a fix for the missing symlinks in the python3 package.

Kind Regards,

Bas

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