Full rebuild after cmake

[conan-io]

Full rebuild after cmake

[memsharded]

I am trying to figure out what could be happening but still no idea. I am working with a normal project (not using cmake-conan), with a conanbuildinfo.cmake, and re-launching project generation and project build, and it doesn't get fully rebuild.

These cmake quirks are quite annoying. What cmake version are you running? I have tried with 3.7. Do you have a fully reproducible behavior of this issue? Thanks!

[koliyo]

It does not rebuild for a small standalone example!

I have found the problem, it is a combination of the conan flag setting and our internal flag modifications. We have a macro to remove flags depending on cmake settings.

MACRO(AGX_REMOVE_CXX_FLAG flag)
  IF (CMAKE_CXX_FLAGS)
    STRING(REGEX REPLACE " *${flag}" "" CMAKE_CXX_FLAGS_TMP ${CMAKE_CXX_FLAGS})
    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS_TMP}" CACHE STRING "" FORCE)
  ENDIF()
ENDMACRO()

Even if this does not change the flag string it modifies some internal cmake state. I have printed CMAKE_CXX_FLAGS before and after calling this macro and it has the same value. But still, this in combination with conan cmake flags will cause whitespace to appear. If I completely remove calls to either conan or AGX_REMOVE_CXX_FLAG then the problem disappear.

I have modifed our macro to only re-set the flags if the regex did some modification.

MACRO(AGX_REMOVE_CXX_FLAG flag)
  IF (CMAKE_CXX_FLAGS)
    STRING(REGEX REPLACE " *${flag}" "" CMAKE_CXX_FLAGS_TMP ${CMAKE_CXX_FLAGS})
    IF (NOT (CMAKE_CXX_FLAGS_TMP STREQUAL CMAKE_CXX_FLAGS))
      SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS_TMP}" CACHE STRING "" FORCE)
    ENDIF()
  ENDIF()
ENDMACRO()

Now I don't see this problem any more.

[memsharded]

Great! Very glad you were able to fix it.
Definitely, the CMake quirks can be a nightmare sometimes. Thanks very much for reporting the solution.

[ilqvya]

maybe it's better to fix it on cmake side so no one need to change their scripts ?...