Switch to cmake for unix

[claudiushaag]

Hi @conda-forge/jansson !

I'm currently working on bringing libraries to conda-forge, which depend on jansson.
These libraries are set up with cmake.
The jansson build of cf for unix systems uses autotools, hence only pkg-config files are written and put into conda-forge.

I now switched the unix build to cmake as well and added a temporary fix for this version for the low cmake minimum version.

Any more input or a merge would be highly appreciated, thanks!

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found it was in an excellent condition.

[claudiushaag]

@mariusvniekerk @xhochy this is a polite ping, maybe it got burried - would love your feedback on this, thank you! :)

[xhochy]

Did you do the checks described in https://conda-forge.org/docs/maintainer/knowledge_base/#moving-from-an-autotools-build-to-a-cmake-build ? Often moving from autotools to cmake breaks the library SONAMEs.

[claudiushaag]

@xhochy very good point, thank you, indeed I did not see that bullet-point. While I can confirm locally that SONAME is the same on linux, the Name of the symbol version seems to change, plus more symbols being exposed.
Running readelf -V shows:
autotools:

Details

Version symbols section '.gnu.version' contains 121 entries:
 Addr: 0x0000000000001ee8  Offset: 0x00001ee8  Link: 3 (.dynsym)
  000:   0 (*local*)       3 (GLIBC_2.3.4)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)
  004:   4 (GLIBC_2.2.5)   1 (*global*)      4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)
  008:   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)
  00c:   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   5 (GLIBC_2.4)     4 (GLIBC_2.2.5)
  010:   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)
  014:   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)
  018:   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   1 (*global*)   
  01c:   6 (GLIBC_2.14)    4 (GLIBC_2.2.5)   3 (GLIBC_2.3.4)   4 (GLIBC_2.2.5)
  020:   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   1 (*global*)   
  024:   4 (GLIBC_2.2.5)   4 (GLIBC_2.2.5)   3 (GLIBC_2.3.4)   2 (libjansson.so.4)  
  028:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  02c:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  030:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  034:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  038:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  03c:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  040:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  044:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  048:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  04c:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  050:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  054:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  058:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  05c:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  060:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  064:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  068:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  06c:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  070:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  074:   2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)     2 (libjansson.so.4)  
  078:   2 (libjansson.so.4)  

Version definition section '.gnu.version_d' contains 2 entries:
 Addr: 0x0000000000001fe0  Offset: 0x00001fe0  Link: 4 (.dynstr)
  000000: Rev: 1  Flags: BASE  Index: 1  Cnt: 1  Name: libjansson.so.4
  0x0014: Rev: 1  Flags: none  Index: 2  Cnt: 1  Name: libjansson.so.4

Version needs section '.gnu.version_r' contains 1 entry:
 Addr: 0x0000000000002010  Offset: 0x00002010  Link: 4 (.dynstr)
  000000: Version: 1  File: libc.so.6  Cnt: 4
  0x0010:   Name: GLIBC_2.14  Flags: none  Version: 6
  0x0020:   Name: GLIBC_2.4  Flags: none  Version: 5
  0x0030:   Name: GLIBC_2.2.5  Flags: none  Version: 4
  0x0040:   Name: GLIBC_2.3.4  Flags: none  Version: 3

cmake:

Details

Version symbols section '.gnu.version' contains 170 entries:
 Addr: 0x0000000000002b1c  Offset: 0x00002b1c  Link: 3 (.dynsym)
  000:   0 (*local*)       3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)
  004:   1 (*global*)      3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)
  008:   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)
  00c:   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   4 (GLIBC_2.4)     3 (GLIBC_2.2.5)
  010:   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)
  014:   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)
  018:   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)
  01c:   1 (*global*)      5 (GLIBC_2.14)    3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)
  020:   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)
  024:   1 (*global*)      3 (GLIBC_2.2.5)   3 (GLIBC_2.2.5)   2 (JANSSON_4)  
  028:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  02c:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  030:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  034:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  038:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  03c:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  040:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  044:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  048:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  04c:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  050:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  054:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  058:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  05c:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  060:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  064:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  068:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  06c:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  070:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  074:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  078:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  07c:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  080:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  084:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  088:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  08c:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  090:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  094:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  098:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  09c:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  0a0:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  0a4:   2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)     2 (JANSSON_4)  
  0a8:   2 (JANSSON_4)     2 (JANSSON_4)  

Version definition section '.gnu.version_d' contains 2 entries:
 Addr: 0x0000000000002c70  Offset: 0x00002c70  Link: 4 (.dynstr)
  000000: Rev: 1  Flags: BASE  Index: 1  Cnt: 1  Name: libjansson.so.4
  0x001c: Rev: 1  Flags: none  Index: 2  Cnt: 1  Name: JANSSON_4

Version needs section '.gnu.version_r' contains 1 entry:
 Addr: 0x0000000000002ca8  Offset: 0x00002ca8  Link: 4 (.dynstr)
  000000: Version: 1  File: libc.so.6  Cnt: 3
  0x0010:   Name: GLIBC_2.14  Flags: none  Version: 5
  0x0020:   Name: GLIBC_2.4  Flags: none  Version: 4
  0x0030:   Name: GLIBC_2.2.5  Flags: none  Version: 3

I have yet to figure out where this comes from. I don't think this is a problem, but I wanted to point it out.
Is this maybe to delicate? Should I instead just add a cmake-shim which disvovers the library for cmake through pkg-config?

janssonConfig.cmake

# janssonConfig.cmake
include_guard(GLOBAL)

if(NOT TARGET jansson::jansson)
  find_package(PkgConfig REQUIRED QUIET)
  pkg_check_modules(JANSSON REQUIRED jansson)

  add_library(jansson::jansson INTERFACE IMPORTED)
  set_target_properties(jansson::jansson PROPERTIES
    INTERFACE_INCLUDE_DIRECTORIES "${JANSSON_INCLUDE_DIRS}"
    INTERFACE_LINK_LIBRARIES "${JANSSON_LIBRARIES}"
  )

  message(STATUS "janssonConfig.cmake shim by conda-forge: created imported target jansson::jansson "
                 "from pkg-config (${JANSSON_VERSION})")
else()
  message(STATUS "janssonConfig.cmake shim: using existing jansson::jansson target")
endif()

set(JANSSON_LIBRARIES "${JANSSON_LIBRARIES}")
set(JANSSON_INCLUDE_DIRS "${JANSSON_INCLUDE_DIRS}")
set(JANSSON_VERSION "${JANSSON_VERSION}")

Thanks for you help.

[xhochy]

If the symbol version changes than I think this would really result in linker error on library load. Probably adding the cmake-shim is the simpler solution for now.

[claudiushaag]

This is a topic which is still in progress upstream, see akheron/jansson#704 and akheron/jansson#715 .
Therefore, I reverted to the shim, and will keep a look onto those issues. The transition can be done afterwards at a later stage.

Thanks @xhochy for having a look!

[claudiushaag]

@xhochy would love your review on this, thank you!
If this is currently not feasible, a quick reaction would help, then I will use another workaround.
Thank you very much.

[xhochy]

Looks good, let's move to CMake once upstream has fixed the issues.