cmake引用了以下导入的目标，但缺少

我有一个带有两个库(liba和libb(的存储库，而liba取决于libb。它们是单个存储库的一部分，是使用单个cmake"上下文"构建的。文件结构如下所示：

├── CMakeLists.txt
├── liba
│   ├── CMakeLists.txt
│   ├── internal
│   │   └── private.hh
│   ├── module.cc
│   ├── module.hh
└── libb
    ├── CMakeLists.txt
    ├── other.cc
    └── other.hh

所有内容都没有任何问题进行编译和安装。虽然，如果我尝试创建一个取决于liba的新项目。喜欢：

cmake_minimum_required(VERSION 3.5)
find_package(Threads REQUIRED)
find_package(OpenCV REQUIRED)
find_package(liba REQUIRED)
add_executable(exec exec.cc)
target_link_libraries(exec PRIVATE is::liba)

我有以下错误：

CMake Error at CMakeLists.txt:5 (find_package):
  Found package configuration file:
    /home/hodor/is-sdk/lib/cmake/liba/libaConfig.cmake
  but it set liba_FOUND to FALSE so package "liba" is considered to be NOT
  FOUND.  Reason given by package:
  The following imported targets are referenced, but are missing: is::libb

我在这里缺少什么？上下文的存储库链接

生成liba的cmakelists：

cmake_minimum_required(VERSION 3.5)
include(GNUInstallDirs)
find_package(OpenCV REQUIRED core)
find_package(Threads REQUIRED)
list(APPEND liba_public_headers 
  "module.hh"
)
list(APPEND liba_private_headers 
  "internal/private.hh"
)
list(APPEND liba_sources 
  "module.cc"
  ${liba_public_headers}
  ${liba_private_headers}
)
add_library(liba ${liba_sources})
target_include_directories(
  liba
 PUBLIC
  $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}> # for headers when building
  $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}> # for generated files in build mode
  $<INSTALL_INTERFACE:include/is/liba> # for clients in install mode
 PRIVATE
  ${OpenCV_INCLUDE_DIRS}
)
target_link_libraries(liba 
 PRIVATE
  is::libb
  ${OpenCV_LIBRARIES} 
  Threads::Threads
)
set_property(TARGET liba PROPERTY CXX_STANDARD 11)
install(
  TARGETS liba EXPORT libaTargets
  LIBRARY  DESTINATION "${CMAKE_INSTALL_LIBDIR}"
  ARCHIVE  DESTINATION "${CMAKE_INSTALL_LIBDIR}"
  RUNTIME  DESTINATION "${CMAKE_INSTALL_BINDIR}"
  INCLUDES  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
)
install(FILES ${liba_public_headers} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/is/liba)
install(
  EXPORT libaTargets
  FILE libaConfig.cmake
  NAMESPACE is::
  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/liba
)

cmakelists：

cmake_minimum_required(VERSION 3.5)
include(GNUInstallDirs)
list(APPEND libb_public_headers 
  "other.hh"
)
list(APPEND libb_sources 
  "other.cc"
  ${libb_public_headers}
)
add_library(libb ${libb_sources})
target_include_directories(
  libb
 PUBLIC
  $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}> # for headers when building
  $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}> # for generated files in build mode
  $<INSTALL_INTERFACE:include/is/libb> # for clients in install mode
)
install(
  TARGETS libb EXPORT libbTargets
  LIBRARY  DESTINATION "${CMAKE_INSTALL_LIBDIR}"
  ARCHIVE  DESTINATION "${CMAKE_INSTALL_LIBDIR}"
  RUNTIME  DESTINATION "${CMAKE_INSTALL_BINDIR}"
  INCLUDES  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
)
install(FILES ${libb_public_headers} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/is/libb)
install(
  EXPORT libbTargets
  FILE libbConfig.cmake
  NAMESPACE is::
  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/libb
)
add_library(is::libb ALIAS libb)

包括liba和libb的顶级cmakelists：

cmake_minimum_required(VERSION 3.5)
add_subdirectory(liba)
add_subdirectory(libb)