Support version specifiers in package.xml (for apt packages)

[murphm8]

Using apt_pkg cache doesn't find a version when searching just by name. If you split the package name into <package_name>=<version> and search <package_name>'s version_list for the version we might be able to install specific versions or verify the version against the desired version in package.xml.

https://stackoverflow.com/questions/34162051/python-apt-install-package-with-specific-version

Update:
With the work done in #117 some version support was added, but it requires workarounds in rosdep to work. The following are changes that would need to be made in colcon-bundle, colcon-ros-bundle, and colcon-ros to add full apt package version specifier support.

In colcon-ros the code located here would need to be updated to parse the version attributes supported in the package.xml format: https://www.ros.org/reps/rep-0140.html#id14. Here's an example of how we set the version metadata from Python setup.cfg packages: https://github.com/colcon/colcon-core/blob/master/colcon_core/package_identification/python.py#L142.

In colcon-ros-bundle this metadata would need to be read and then converted to the format supported in

colcon-bundle/colcon_bundle/installer/apt.py

Line 157 in a85d262

def _separate_version_information(self, package_name):

. Currently, the apt installer in colcon-bundle only supports =. Support for other version specifiers might be desirable, since those specifiers are part of the package.xml spec.

[khaiyichin]

Hi, any update on this? If I need a version that's later than the one colcon bundle finds, will this be the only way to do it?

[murphm8]

@khaiyichin Generally speaking if you are pulling packages from the main apt repositories there is only one version of a given package available. This feature would allow you to host your own apt repository with multiple versions of a package, and then specify which version gets installed. So, if you're looking for a later version of a package you would most likely need to create your own repo as the main apt repositories lag behind especially as a distribution gets older.