解决方法：

rm -rf Podfile.lock

rm -rf Pods/

pod install

pod install

Analyzing dependencies

Downloading dependencies

xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

――― MARKDOWN TEMPLATE ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――

### Command

```

/Users/user/.rvm/rubies/ruby-2.6.6/bin/pod install

```

### Report

* What did you do?

* What did you expect to happen?

* What happened instead?

### Stack

```

   CocoaPods : 1.9.3

Ruby : ruby 2.6.6p146 (2020-03-31 revision 67876) [x86_64-darwin19]

RubyGems : 3.0.8

Host : Mac OS X 10.15.5 (19F101)

   Xcode : ()

   Git : git version 2.24.3 (Apple Git-128)

Ruby lib dir : /Users/user/.rvm/rubies/ruby-2.6.6/lib

Repositories : aliyun - git - https://github.com/aliyun/aliyun-specs.git @ dbad14ebc678e5bd343fb0a14028261e94f14787

   cocoapods - git - https://github.com/CocoaPods/Specs.git @ 77c0789567a57c1e5ff50eaef628ba9e65286566

   taobao-baichuansdk-alibcspecs - git - http://repo.baichuan-ios.taobao.com/baichuanSDK/AliBCSpecs.git @ ca0454d5afe49986afe11d8d2869c268e1439bd3

   trunk - CDN - https://cdn.cocoapods.org/

```

### Plugins

```

cocoapods-deintegrate : 1.0.4

cocoapods-plugins : 1.0.0

cocoapods-search : 1.0.0

cocoapods-stats : 1.1.0

cocoapods-trunk : 1.5.0

cocoapods-try : 1.2.0

```

### Podfile

```ruby

# Uncomment the next line to define a global platform for your project

source 'https://github.com/CocoaPods/Specs.git'

Xxxx

#post_install do |installer|

# copy_pods_resources_path = "Pods/Target Support Files/Pods-CouponApp/Pods-CouponApp-resources.sh"

# text = File.read(copy_pods_resources_path)

# string_onceCopy = File.read("copy_pod_resources_once.patch")

# string_time = Time.now.strftime("%Y%m%d%H%M%S")

# string_onceCopy = string_onceCopy.gsub("#Time#", string_time)

# text = text.gsub("set -e", string_onceCopy)

# File.open(copy_pods_resources_path, "w") {|file| file.puts text}

#end

# Prevent Cocoapods from embedding a second Flutter framework and causing an error with the new Xcode build system.

install! 'cocoapods', :disable_input_output_paths => true

```

### Error

```

NoMethodError - undefined method `size' for nil:NilClass

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/macho_file.rb:455:in `populate_mach_header'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/macho_file.rb:233:in `populate_fields'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/macho_file.rb:55:in `initialize_from_bin'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/macho_file.rb:33:in `new_from_bin'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/fat_file.rb:365:in `block in populate_machos'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/fat_file.rb:364:in `each'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/fat_file.rb:364:in `populate_machos'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/fat_file.rb:156:in `populate_fields'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho/fat_file.rb:95:in `initialize'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho.rb:31:in `new'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/ruby-macho-1.4.0/lib/macho.rb:31:in `open'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/xcode/linkage_analyzer.rb:16:in `dynamic_binary?'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/sandbox/file_accessor.rb:171:in `block in vendored_dynamic_frameworks'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/sandbox/file_accessor.rb:170:in `select'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/sandbox/file_accessor.rb:170:in `vendored_dynamic_frameworks'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/sandbox/file_accessor.rb:179:in `vendored_static_frameworks'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/sandbox/file_accessor.rb:292:in `vendored_static_artifacts'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer/xcode/target_validator.rb:82:in `each'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer/xcode/target_validator.rb:82:in `flat_map'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer/xcode/target_validator.rb:82:in `block (2 levels) in verify_no_static_framework_transitive_dependencies'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer/xcode/target_validator.rb:74:in `each_key'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer/xcode/target_validator.rb:74:in `block in verify_no_static_framework_transitive_dependencies'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer/xcode/target_validator.rb:73:in `each'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer/xcode/target_validator.rb:73:in `verify_no_static_framework_transitive_dependencies'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer/xcode/target_validator.rb:38:in `validate!'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer.rb:590:in `validate_targets'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/installer.rb:158:in `install!'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/command/install.rb:52:in `run'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/claide-1.0.3/lib/claide/command.rb:334:in `run'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/lib/cocoapods/command.rb:52:in `run'

/Users/user/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/cocoapods-1.9.3/bin/pod:55:in `<top (required)>'

/Users/user/.rvm/rubies/ruby-2.6.6/bin/pod:23:in `load'

/Users/user/.rvm/rubies/ruby-2.6.6/bin/pod:23:in `<main>'

/Users/user/.rvm/gems/ruby-2.6.6/bin/ruby_executable_hooks:24:in `eval'

/Users/user/.rvm/gems/ruby-2.6.6/bin/ruby_executable_hooks:24:in `<main>'

```

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[!] Oh no, an error occurred.

Search for existing GitHub issues similar to yours:

https://github.com/CocoaPods/CocoaPods/search?q=undefined+method+%60size%27+for+nil%3ANilClass&type=Issues

If none exists, create a ticket, with the template displayed above, on:

https://github.com/CocoaPods/CocoaPods/issues/new

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https://github.com/CocoaPods/CocoaPods/blob/master/CONTRIBUTING.md

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