ProductBuild CPack generator doesn't log error output
As I see at Source/CPack/cmCPackProductBuildGenerator.cxx:150, the error output from the commands are stored in the error_output
variable and then simply discarded. In case of an error result from the command (line 157), only the standard output of the command is written to the log file which is not often very useful without the standard error.
I would suggest that the error output from the command be also appended to the log.