CPack DEB generator shlibdeps fails silently if /usr/bin/file is not installed

[Henning Meyer]

I use CPack to build a debian package

I use CPACK_DEBIAN_PACKAGE_SHLIBDEPS to let dpkg-shlibdeps figure out shared library dependencies

this only works when the package "file" is installed and fails silently otherwise

"file" is not a package dependency of the cmake package

this bug report is about the packaging dependency, not that cpack silently fails, which should be fixed upstream

How to reproduce

Source File: main.cxx

#include <iostream>
int main(int,char**) {
std::cout << "Hello\n";
return 0;
}

CMakeList.txt:
cmake_minimum_required(VERSION 2.6)

PROJECT(Hello)

ADD_EXECUTABLE(hello main.cxx)
INSTALL(TARGETS hello DESTINATION hello)

SET(CPACK_GENERATOR "DEB")
SET(CPACK_DEBIAN_PACKAGE_MAINTAINER "Hello Kitty") #required
SET(CPACK_DEBIAN_PACKAGE_SHLIBDEPS ON)
INCLUDE(CPack)

commands to trigger
apt install cmake
cmake .
make package
dpkg -I Hello-0.1.1-Linux.deb | grep Depends

expected output:
Depends: libc6 (>= 2.2.5), libstdc++6 (>= 4.1.1)

actual output of grep if /usr/bin/file is not installed is empty (missing Depends line)

affects Ubuntu version: Ubuntu 16.04 (probably all others too)
affects cmake version: 3.5.1-1ubuntu1

Work-around: apt install file (almost everyone has that installed, but minimal docker containers for package building do not)

suggested solution: make the cmake package depend on the file package

[Gianfranco Costamagna (costamagnagianfranco)]

Forwarding to Debian

[Gianfranco Costamagna (costamagnagianfranco)]

please forward upstream the "silently fails" bug, I should have found the corresponding code in the Debian bug report.

[Henning Meyer (henning.meyer)]

Yes, I will report this in cmake upstream later today

[Henning Meyer (henning.meyer)]

I have described the issue on the <email address hidden> mailing list as follows:

the CPack DEB generator executes the file tool to determine whether a
file is executable

this is a snippet from CPackDeb.cmake from cmake gitlab master:

# get file info so that we can determine if file is executable or not
    unset(CPACK_DEB_INSTALL_FILES)
    foreach(FILE_ IN LISTS FILE_PATHS_)
      execute_process(COMMAND file "./${FILE_}"
        WORKING_DIRECTORY "${WDIR}"
        OUTPUT_VARIABLE INSTALL_FILE_)
      list(APPEND CPACK_DEB_INSTALL_FILES "${INSTALL_FILE_}")
    endforeach()

    # Only dynamically linked ELF files are included
    # Extract only file name infront of ":"
    foreach(_FILE IN LISTS CPACK_DEB_INSTALL_FILES)
      if(_FILE MATCHES "ELF.*dynamically linked")
        string(REGEX MATCH "(^.*):" _FILE_NAME "${_FILE}")
        list(APPEND CPACK_DEB_BINARY_FILES "${CMAKE_MATCH_1}")
        set(CONTAINS_EXECUTABLE_FILES_ TRUE)
      endif()
      if(_FILE MATCHES "ELF.*shared object")
        string(REGEX MATCH "(^.*):" _FILE_NAME "${_FILE}")
        list(APPEND CPACK_DEB_SHARED_OBJECT_FILES "${CMAKE_MATCH_1}")
      endif()
    endforeach()

The problem is that execute_process(COMMAND file) may fail, and if it
does, we do not add the dependencies of that executable to the generated
deb file. This issue happened to us because our continuous integration
system tried building inside a minimal docker image, where /usr/bin/file
was simply not available, but it might fail for other reasons too: for
example strange things in the user's path, open file limit exceeded or
out of memory conditions.

I would therefore much prefer if the above code:
1) uses a variable ${FILE_EXECUTABLE} for the file tool defaulting to
/usr/bin/file similar to the way it uses the variable
${READELF_EXECUTABLE} for the readelf tool
2) checks the return code on every iteration of the foreach() loop, and
calls message(FATAL_ERROR) if it is non-zero.

[Gianfranco Costamagna (costamagnagianfranco)]

thanks, I think an issue might be better, rather than a mail list post...

[Henning Meyer (henning.meyer)]

Good point:

I have opened issue #16486 and will create a merge request

https://gitlab.kitware.com/cmake/cmake/issues/16486

[Henning Meyer (henning.meyer)]

the "silent failure" issue has been fixed in cmake upstream:

https://gitlab.kitware.com/cmake/cmake/commit/e326d8cf3eb2ac3f98fe5b4783b35c6141c006a9

[Gianfranco Costamagna (costamagnagianfranco)]

Marking as fix released because I'll sync for next AA series