diff --git a/mo2_python.cmake b/mo2_python.cmake
index c8af496..be0f00d 100644
--- a/mo2_python.cmake
+++ b/mo2_python.cmake
@@ -49,9 +49,13 @@ function(mo2_python_pip_install TARGET)
 
 	string(MAKE_C_IDENTIFIER "${MO2_PACKAGES}" PIP_FILE_LOG)
 	set(pip_log_file "${CMAKE_CURRENT_BINARY_DIR}/${PIP_FILE_LOG}.log")
+	set(_success_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}_requirements_success.log")
 
+	# there is no way to guess a file generated by pip except the log file, but the log
+	# file is always generated (even on failure), so we run a second command after pip
+	# (only if pip succeeds) to generate a success file that we can depend on
 	add_custom_command(
-		OUTPUT "${pip_log_file}"
+		OUTPUT "${_success_file}"
 		COMMAND ${PYTHON_EXE}
 				-I
 				-m pip
@@ -64,11 +68,12 @@ function(mo2_python_pip_install TARGET)
 				--target="${MO2_DIRECTORY}"
 				--log="${pip_log_file}"
 				${MO2_PACKAGES}
+		COMMAND ${PYTHON_EXE} -c "open('${_success_file}', 'w').close()"
 	)
 
 	set(pip_target_name "${TARGET}_pip_${PIP_FILE_LOG}")
 
-	add_custom_target(${pip_target_name} ALL DEPENDS "${pip_log_file}")
+	add_custom_target(${pip_target_name} ALL DEPENDS "${pip_log_file}" "${_success_file}")
 	set_target_properties(${pip_target_name} PROPERTIES FOLDER autogen)
 
 	add_dependencies(${TARGET} ${pip_target_name})
@@ -154,20 +159,29 @@ endfunction()
 function(mo2_python_requirements TARGET)
 	cmake_parse_arguments(MO2 "" "LIBDIR" "" ${ARGN})
 
+	set(_success_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}_requirements_success.log")
+
 	mo2_find_python_executable(PYTHON_EXE)
+
+	# there is no way to guess a file generated by pip except the log file, but the log
+	# file is always generated (even on failure), so we run a second command after pip
+	# (only if pip succeeds) to generate a success file that we can depend on
 	add_custom_command(
-		OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pip.log"
+		OUTPUT "${_success_file}"
 		COMMAND ${PYTHON_EXE}
 				-I
 				-m pip
-				install --force --upgrade --disable-pip-version-check
+				install
+				--force
+				--upgrade
+				--disable-pip-version-check
 				--target="${MO2_LIBDIR}"
 				--log="${CMAKE_CURRENT_BINARY_DIR}/pip.log"
 				-r "${PROJECT_SOURCE_DIR}/plugin-requirements.txt"
+		COMMAND ${PYTHON_EXE} -c "open('${_success_file}', 'w').close()"
 		DEPENDS "${PROJECT_SOURCE_DIR}/plugin-requirements.txt"
 	)
-	add_custom_target("${TARGET}_libs"
-		ALL DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pip.log")
+	add_custom_target("${TARGET}_libs" ALL DEPENDS "${_success_file}")
 	set_target_properties("${TARGET}_libs" PROPERTIES FOLDER autogen)
 
 	add_dependencies(${TARGET} "${TARGET}_libs")