Use of embedded external dependencies #4221
Description
Following the remarks we got from the SOFA conda package PR on conda-forge (conda-forge/staged-recipes#23085), we have some problems regarding some external libraries that are embedded in SOFA code.
Here is a try to sum up all of these embedded libraries:
| Lib name | Type | Location in code | License | Status |
|---|---|---|---|---|
| difflib | header-only | extlibs |
MIT | OK |
| json nlohmann | header-only | extlibs |
MIT |
OK. Fixed in #4272 |
| stb | header-only | extlibs |
MIT | OK |
| TinyXML | static | extlibs |
zlib (should be in a separate file) | Externalize tinyxml dependency: #4240 (waiting for merge) |
| miniFlowVR | static | applications/plugins/SofaDistanceGrid/extlibs |
LGPL (version ?) (should be in a separate file) | Not built by default. TODO: plugin to be externalized (#1442 ) |
| newmat | static | applications/plugins/SofaNewmat/extlibs |
type inconnu | Not built by default. TODO: plugin to be externalized (#1442 ) |
| CImg | header-only | applications/plugins/CImgPlugin/extlibs |
CeCILL-C / CeCILL | OK |
| csparse | static | Sofa/Component/LinearSolver/Direct/extlibs |
no license file | Plugin to be externalized. WIP : #4258 |
| metis | static | Sofa/Component/LinearSolver/Direct/extlibs |
Apache v2 | Externalize metis dependency : #4266 (waiting for merge) |
| gtest | shared | Sofa/framework/Testing/extlibs |
BSD-3-Clause | Externalize ? |
| cxxopts | header-only | Sofa/GUI/Common (fetched from GitHub) |
MIT | Add to possibility to use external dependency and prevent from fetching: Fixed in #4273 |
| libQGLViewer | shared | Sofa/GUI/Qt |
GPL | Find or use embedded code (find module being fixed in #4290) |
The actions we should take to make our code compatible for the conda package on conda-forge are:
- Fix the missing licenses files (points in bold)
- Avoid all static libraries.
For point 2, we are not concerned by miniFlowVR and newmat, as we do not compile the corresponding plugins for the conda package, at least for now. Before considering any action on these two, do the SofaDistanceGrid and SofaNewmat plugins are still used and planned to be maintained in future releases ?
Regarding other static libs (TinyXML, csparse and metis), could we consider to switch to an external dependency instead ? For TinyXML, the current behavior is to first look for an external package, and fallback to embedded version if unavailable. This looks reasonable at first, but shouldn't we switch to fully externalized versions for maintainability ?
Last point, we were also advised to use external dependency for some header-only libraries, especially when they are already packaged in conda-forge. Could we consider also to use externalized versions for some of these (the ones easily available as external packages), such as json nlohmann and cxxopts ?