Create thread-safe storage of source-space paths

[jbohren]

Currently, as described in #670, when multiple catkin cmake processes are running with a merged develspace, they each want to modify devel/.catkin in order to store the sourcespace paths for each package. This information is used to build PATH-like variables like $ROS_PACKAGE_PATH.

If a parallel-safety flag is set, as proposed in #675, then we could generate this file with a top-level tool like catkin build.

[dirk-thomas]

Please consider to provide a pull request for this.

[dirk-thomas]

I assume catkin_tools addresses the need in its own way and this ticket can be closed?

[jbohren]

I assume catkin_tools addresses the need in its own way and this ticket can be closed?

No, catkin_tools doesn't address this.

[dirk-thomas]

I will close this issue for now since it is unlikely that anyony is working on this in the future and it is unclear how this could be addressed in catkin itself.

Imo the build tool should avoid performing tasks in parallel which access the same files, e.g. by passing CATKIN_BUILD_BINARY_PACKAGE and generating these files itself.