Improvements to ament_lint_clang_tidy.

[nuclearsandwich]

Without this default in the hook script ament_clang_tidy does not execute properly.

This is still in draft while I determine why a default is needed in CMake when the python script wrapping clang-tidy should be handling the default instead.

The second commit updates the script to check for more than just clang-tidy-6.0.

[audrow]

This looks okay to me, once you feel good about the reason a default is needed.

[nuclearsandwich]

Okay so I spent some time refreshing myself on these changes. I have some reservations about the hook script having a default argument if the default instead ought to be pushed further up, either in the ament_clang_tidy() cmake function or in the ament_clang_tidy script. ament_clang_tidy defaults to looking in os.curdir and when run via ament_cmake_clang_tidy the working directory is the source directory. In this default state for an out-of-tree build it will fail since the compile commands database file required by clang-tidy is in the build directory rather than the source directory. But in a local test where I changed the working directory to the build directory it fails to locate source files properly.

I am less concerned with the hook containing a default argument after scrolling through some of the other hook scripts. Both ament_cppcheck and ament_cpplint have default variables.

[mwcondino]

Hey @nuclearsandwich , I was curious if there was an ETA on this PR? I'm looking into adding ament_clang_tidy into a project and it would be a little more ergonomic with these proposed changes merged.

[nuclearsandwich]

I don't have an exact ETA but I did dig into this issue a bit further and re-assure myself that this approach is at least valid although I wish I could find a way to push the appropriate default argument down into the called CMake function rather than the hook script but I didn't find a way that worked as I expected.

[nuclearsandwich]

• Linux
• Linux-aarch64
• macOS
• Windows

ament_cmake_clang_tidy isn't enabled by default in ament_lint_common so won't be used by default in any ROS 2 packages, but I wanted to make sure that the packages still build and that tests still run coherently with these changes, especially on non-linux platforms. So this CI run runs test_rclcpp tests along with building and testing ament_cmake_clang_tidy.