Add link directory to support curl 8.12 (open-telemetry#3272)

Author: owent

exporters/otlp/CMakeLists.txt

@@ -119,8 +119,12 @@ if(WITH_OTLP_HTTP)
   target_link_libraries(
     opentelemetry_exporter_otlp_http_client
     PUBLIC opentelemetry_sdk opentelemetry_ext
-    PRIVATE opentelemetry_proto opentelemetry_http_client_curl
-            nlohmann_json::nlohmann_json)
+    # Links flags of opentelemetry_http_client_curl should be public when
+    # building internal components
+    PRIVATE opentelemetry_proto
+            "$<BUILD_INTERFACE:opentelemetry_http_client_curl>"
+            nlohmann_json::nlohmann_json
+            "$<INSTALL_INTERFACE:opentelemetry_http_client_curl>")
   if(TARGET absl::strings)
     target_link_libraries(opentelemetry_exporter_otlp_http_client
                           PUBLIC absl::strings)

ext/src/http/client/curl/CMakeLists.txt

@@ -10,11 +10,33 @@ set_target_properties(opentelemetry_http_client_curl
 set_target_version(opentelemetry_http_client_curl)
 target_link_libraries(opentelemetry_http_client_curl
                       PUBLIC opentelemetry_common)
-if(TARGET CURL::libcurl)
+
+unset(CURL_IMPORTED_TARGET_NAME)
+
+foreach(FIND_CURL_IMPORTED_TARGET CURL::libcurl CURL::libcurl_shared
+                                  CURL::libcurl_static)
+  if(TARGET ${FIND_CURL_IMPORTED_TARGET})
+    set(CURL_IMPORTED_TARGET_NAME ${FIND_CURL_IMPORTED_TARGET})
+    break()
+  endif()
+endforeach()
+
+if(TARGET ${CURL_IMPORTED_TARGET_NAME})
   target_link_libraries(
     opentelemetry_http_client_curl
     PUBLIC opentelemetry_ext
-    PRIVATE CURL::libcurl)
+    PRIVATE ${CURL_IMPORTED_TARGET_NAME})
+
+  # Some versions of libcurl do not export the link directories, which may cause
+  # link errors
+  project_build_tools_get_imported_location(CURL_LIB_FILE_PATH
+                                            ${CURL_IMPORTED_TARGET_NAME})
+  get_filename_component(CURL_LIB_DIR_PATH "${CURL_LIB_FILE_PATH}" DIRECTORY)
+
+  if(CURL_LIB_DIR_PATH)
+    target_link_directories(opentelemetry_http_client_curl PUBLIC
+                            "$<BUILD_INTERFACE:${CURL_LIB_DIR_PATH}>")
+  endif()
 else()
   target_include_directories(opentelemetry_http_client_curl
                              INTERFACE "${CURL_INCLUDE_DIRS}")

ext/test/http/CMakeLists.txt

@@ -8,14 +8,25 @@ if(WITH_HTTP_CLIENT_CURL)
   target_link_libraries(${FILENAME} ${GMOCK_LIB} ${GTEST_BOTH_LIBRARIES}
                         ${CMAKE_THREAD_LIBS_INIT})
 
-  if(TARGET CURL::libcurl)
+  unset(CURL_IMPORTED_TARGET_NAME)
+
+  foreach(FIND_CURL_IMPORTED_TARGET CURL::libcurl CURL::libcurl_shared
+                                    CURL::libcurl_static)
+    if(TARGET ${FIND_CURL_IMPORTED_TARGET})
+      set(CURL_IMPORTED_TARGET_NAME ${FIND_CURL_IMPORTED_TARGET})
+      break()
+    endif()
+  endforeach()
+
+  if(TARGET ${CURL_IMPORTED_TARGET_NAME})
     target_link_libraries(${FILENAME} opentelemetry_http_client_curl
-                          opentelemetry_common CURL::libcurl)
+                          opentelemetry_common ${CURL_IMPORTED_TARGET_NAME})
   else()
     include_directories(${CURL_INCLUDE_DIRS})
     target_link_libraries(${FILENAME} ${CURL_LIBRARIES}
                           opentelemetry_http_client_curl opentelemetry_common)
   endif()
+
   gtest_add_tests(
     TARGET ${FILENAME}
     TEST_PREFIX ext.http.curl.