[Ros-release] ABI compatibility

[Brian Gerkey]

hi Rich,

Very helpful, thanks for the detailed analysis!

We're going to look into running some of those tools (probably pkgdiff
to start) against our own packages when we do releases.

It would be *great* to run that sort of tool in the ROS release
system/process.  At least to provide a warning, if not behave as an
interlock.

    brian.

On Thu, Jan 3, 2013 at 12:23 PM, Rich Mattes <richmattes at gmail.com> wrote:
> On 01/03/2013 02:01 PM, Brian Gerkey wrote:
>>
>> hi,
>>
>> We recently experienced the following problem: a binary deb that we
>> build against ROS Fuerte started producing mysterious crashes when
>> installed on a fresh system.  It had previously been working fine, and
>> still worked fine on some not-freshly installed systems.
>>
>> After a bit of head-scratching, we hypothesized that something had
>> changed in the underlying Fuerte debs.  So we tried compiling our
>> code, without changes, against the latest Fuerte debs.  That worked
>> fine.  So we did a no-op re-release of our package, to produce a new
>> deb built against the latest Fuerte debs.  That works fine, too. So,
>> for now, our problem is solved.
>
>
> Looks like you were right about the symbols.  I ran pkg-diff against the
> drcsim 1.3.0 and 1.3.1 debs.  The library
> libgazebo_ros_controller_manager.so in drcsim-1.3.0 depends on a symbol
> called _ZN19pr2_mechanism_model10RobotStateD1 Ev that it doesn't depend on
> in 1.3.1.  Digging deeper, this symbol is provided by
> libpr2_controller_manager.so in ros-fuerte-pr2-mechanism-1.6.1, and gone in
> ros-fuerte-pr2-mechanism-1.6.4.  The reason looks to be that the RobotState
> class changed between 1.6.1 and 1.6.4 in the
> pr2_mechanism/pr2_mechanism_model/include/pr2_mechanism_model/robot.h
> header.  Specifically, the RobotState class is inheriting HardwareInterface.
> A diff of the two versions of robot.h:
>
> ---
> ./1.6.1/opt/ros/fuerte/stacks/pr2_mechanism/pr2_mechanism_model/include/pr2_mechanism_model/robot.h
> 2012-11-02 18:46:10.000000000 -0400
> +++
> ./1.6.4/opt/ros/fuerte/stacks/pr2_mechanism/pr2_mechanism_model/include/pr2_mechanism_model/robot.h
> 2012-12-26 18:54:49.000000000 -0500
> @@ -51,6 +51,7 @@
>  #include <string>
>  #include <urdf/model.h>
>  #include <pr2_hardware_interface/hardware_interface.h>
> +#include <hardware_interface/hardware_interface.h>
>  #include "pr2_mechanism_model/joint.h"
>  #include "pr2_mechanism_model/transmission.h"
>
> @@ -130,7 +131,7 @@ private:
>   * Some specialized controllers (such as the calibration controllers) can
> get access
>   * to actuator states, and transmission states.
>   */
> -class RobotState
> +class RobotState : public hardware_interface::HardwareInterface
>  {
>  public:
>    /// constructor
> @@ -185,7 +186,6 @@ public:
>    void zeroCommands();
>
>
> -private:
>    std::map<std::string, JointState*> joint_states_map_;
>
>  };
>
> There are a few tools that can be used by the buildsystem to compare new
> builds to the ones that already exist.  pkgdiff is one that can be used
> offline on two .deb files.  The other two are abi-compliance-checker and
> api-sanity-checker.  These both require that a package be installed with all
> of its dependencies around, but they can generate much better reports of
> library symbols that are added and removed (pkgdiff required some manual
> digging). upstream-tracker.org is a good example of a service that runs
> these tools on new releases of open-source libraries.
>
> There were some other removals and reorganizations of packages between the
> two versions of pr2-controllers and pr2-mechanism as well, I threw
> everything up online[1][2][3] if you're interested in browsing them.
>
> Rich
>
> [1]
> http://richmattes.com/pkgdiff_reports/drcsim/1.3.0_to_1.3.1/compat_report.html
> [2]
> http://richmattes.com/pkgdiff_reports/ros-fuerte-pr2-controllers/1.8.0-s1351921336~precise_to_1.8.1-s1356572075~precise/compat_report.html
> [3]
> http://richmattes.com/pkgdiff_reports/ros-fuerte-pr2-mechanism/1.6.1-s1351920681~precise_to_1.6.4-s1356571098~precise/compat_report.html
>
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