我尝试了我搜索过的所有内容，例如重新安装我的cocoapods，更新我的gem或cocoapads的版本，但它不起作用。错误日志如下所示：
/Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/metadata.rb:15:in `initialize': undefined method `with_indifferent_access' for false:FalseClass (NoMethodError)
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/metadata.rb:28:in `new'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/metadata.rb:28:in `from_file'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source.rb:434:in `refresh_metadata'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/cdn_source.rb:55:in `refresh_metadata'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source.rb:31:in `initialize'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/cdn_source.rb:29:in `initialize'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/manager.rb:310:in `new'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/manager.rb:310:in `block in source_from_path'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/manager.rb:315:in `source_from_path'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/manager.rb:324:in `block in aggregate_with_repos'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/manager.rb:324:in `map'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/manager.rb:324:in `aggregate_with_repos'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/manager.rb:24:in `aggregate'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-core-1.8.4/lib/cocoapods-core/source/manager.rb:58:in `all'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-1.8.4/lib/cocoapods/user_interface/error_report.rb:173:in `repo_information'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-1.8.4/lib/cocoapods/user_interface/error_report.rb:77:in `stack'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-1.8.4/lib/cocoapods/user_interface/error_report.rb:24:in `report'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-1.8.4/lib/cocoapods/command.rb:66:in `report_error'
from /Library/Ruby/Gems/2.3.0/gems/claide-1.0.3/lib/claide/command.rb:396:in `handle_exception'
from /Library/Ruby/Gems/2.3.0/gems/claide-1.0.3/lib/claide/command.rb:337:in `rescue in run'
from /Library/Ruby/Gems/2.3.0/gems/claide-1.0.3/lib/claide/command.rb:324:in `run'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-1.8.4/lib/cocoapods/command.rb:52:in `run'
from /Library/Ruby/Gems/2.3.0/gems/cocoapods-1.8.4/bin/pod:55:in `<top (required)>'
from /usr/local/bin/pod:23:in `load'
from /usr/local/bin/pod:23:in `<main>'
感谢您对我的帮助，终于找到了这个问题的原因。那是因为我有三个不同版本的Xcode。但我只使用最新版本。因此，当我切换Xcode的默认版本时，问题就解决了。 就像： sudo xcode-select --switch [your xcode path]。