[PROTON-2254] Relative paths in CMake share

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: proton-c-0.31.0
• Fix Version/s: proton-c-0.36.0
• Component/s: build, cpp-binding, proton-c
• Labels: cmake install proton

Environment

Debian Linux; build Proton then Dispatch into each their own `DESTDIR`. This is done by our "layered build" system, https://gitlab.com/arpa2/mkhere/-/blob/master/qpid_proton.sh and https://gitlab.com/arpa2/mkhere/-/blob/master/qpid_dispatch.sh

• Assignee: Jiri Daněk
• Reporter: Rick van Rein
• Created: 28/Jul/20 06:03
• Updated: 18/Nov/21 11:05
• Resolved: 29/Oct/21 17:39

Description

This sequency installs well:

cmake
make
make DESTDIR=/some/where install

However, further use of the installation fails, because of strict dependencies on the installed paths in files like `ProtonConfig.cmake`:

set_target_properties(Proton::core
PROPERTIES
IMPORTED_LOCATION "/usr/local/lib/libqpid-proton-core.so"
IMPORTED_LOCATION_DEBUG "/usr/local/lib/libqpid-proton-core.so"
INTERFACE_INCLUDE_DIRECTORIES "${Proton_Core_INCLUDE_DIRS}")

*What would work:* First switch to the `DESTDIR`, then continue building something like Qpid Dispatch Router.

*Solution:* Use relative directories, like in:

# Compute the installation prefix relative to this file.
get_filename_component(_IMPORT_PREFIX "${CMAKE_CURRENT_LIST_FILE}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
if(_IMPORT_PREFIX STREQUAL "/")
set(_IMPORT_PREFIX "")
endif()

*Work-around:* An unhappy quickfix is

find /some/where -name *.cmake -exec \
     sed -i "s+/usr/+/some/where/usr/+g" {} \;

Issue Links

• causes: PROTON-2433 The work for PROTON-2254 seems to have broken modern use of CMake