Bug#826050: Faulty CMake file impairs compiling against VTK

[Peter Mattern]

Source: vtk6
Version: 6.3.0+dfsg1-1, 6.2.0+dfsg1-11.1
Severity: important

Compiling recent Ginkgo CADx against VTK on Debian testing yields two cmake warnings which
suggest there are corresponding errors in the packaging of VTK.

> -- The imported target "vtkRenderingPythonTkWidgets" references the file
>    "/usr/lib/x86_64-linux-gnu/libvtkRenderingPythonTkWidgets.so"
> but this file does not exist.  Possible reasons include:
> * The file was deleted, renamed, or moved to another location.
> * An install or uninstall procedure did not complete successfully.
> * The installation package was faulty and contained
>    "/usr/lib/cmake/vtk-6.2/VTKTargets.cmake"
> but not all the files it references.

A library libvtkRenderingPythonTkWidgets.so was provided by package libvtk6-dev in jessie
(VTK 6.1) but no longer exists as of stretch (VTK 6.2). The library does still exist in more
recent versions of VTK as can be seen with VTK 7.0.0 on Arch Linux, 6.3 on Arch Linux or
openSUSE Leap 42.1 and 6.2 on Fedora 23. In all these distributions the naming is the
typical libvtkRenderingPythonTkWidgets*-<VTK version>*.so that VTK upstream is using to name
the third-party libraries imported into the VTK source tree, though.

> -- The imported target "vtk" references the file
>    "/usr/bin/vtk"
> but this file does not exist.  Possible reasons include:
> * The file was deleted, renamed, or moved to another location.
> * An install or uninstall procedure did not complete successfully.
> * The installation package was faulty and contained
>    "/usr/lib/cmake/vtk-6.2/VTKTargets.cmake"
> but not all the files it references.

A binary /usr/bin/vtk is provided by package tcl-vtk in jessie but is no longer available in
stretch. Package vtk6 in both stretch and jessie is providing a binary /usr/bin/vtk6 only.

All findings are the same when the VTK binary packages of testing are replaced with their
counterparts from sid plus their additional new or changed dependencies.

The reason to assume it's a packaging issue in Debian is the fact that the warning messages
can not be seen when the same Ginkgo CADx checkout gets compiled against the same VTK version
on Arch Linux where packaging does not involve any tweaking of VTK's paths.

On a side note I'm wondering whether it's on purpose that packages libvtk6.3[-qt] as well as
libvtk6.2[-qt] are stated as belonging to source package vtk6 (6.3) of sid at
https://packages.debian.org/source/sid/vtk6.

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.5.0-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

-- no debconf information