Use the podspec :subspec=>'xx' to load dependencies from a subspec

[Whirlwind]

Sometimes, I use the podspec in a Podfile to load dependencies from a .podspec file. But I often just load one or some subspec(s) from the podspec file, not load all dependencies.
eg: this is a Podspec:

s.dependency 'SDWebImage'
s.subspec 'ASI' do |s1|
    s1.dependency 'ASIHTTPRequest'
end
s.subspec 'AF' do |s2|
    s2.dependency 'AFNetworking'
end

this is a Podfile:

target :SDKForASI do
    podspec :subspec=>'ASI'
end
target :SDKForAF do
    podspec :subspec=>'AF'
end

I need the target have different dependencies from different subspecs. This PR will add a option subspec(subspecs) to the podspec DSL.

[amorde]

I don't understand the issue this is trying to fix. How is this different from just specifying the subspec directly? Like this:

target :SDKForASI do
    pod 'MySDK/ASI'
end
target :SDKForAF do
    pod 'MySDK/AF'
end

[Whirlwind]

Maybe I lost some description. The project and targets are the development pods.
The MySDK/ASI's source_files will be installed in Pods project and build target Pods-MySDK-ASI.a. But my target SDKForASI includes the source_files and has been compiled by xcode. So If I use pod 'MySDK/ASI', I will get duplicate symbols and classes.

If I use podspec, CocoaPods will only pick the dependencies from podspec file, will not install the MySDK.

[amorde]

Ah, okay. So you're using this syntax https://guides.cocoapods.org/syntax/podfile.html#podspec to load the dependencies of the podspec.

Is the issue that you want only the dependencies of the subspec, and not the dependencies of the root spec? Does podspec :name => 'MySDK/ASI' not support what you're trying to do?

[Whirlwind]

The name is used to search the podspec file, it could not pick the dependencies from subspec.

[amorde]

Ok thanks, I think I understand now

[amorde]

Looks good! A couple comments, and would like a least 1 other person to review

[amorde]

I think its worth adding only the plural :subspecs option to keep the implementation simpler. If you only want 1 subspec, that could just be :subspecs => ['Subspec']

[Whirlwind]

I think about it. But I found that I often only use one subspec in a target, so the :subspec=>'xx' is very simple and very common.

[amorde]

Could this raise an error if the type is incorrect? Like if we receive :subspecs => [1234]

[Whirlwind]

Is it strange that each parameter determines the type?

[amorde]

Well they sort of have a type already, even if its implicit rather than explicit. Passing a Hash or something else into :subspecs doesn't really make sense

[Whirlwind]

add subspec_names.map!(&:to_s) ?

[Whirlwind]

It seams that it will not raise an error if the subspecs => [1234].

          subspec_names = options[:subspecs] || options[:subspec]
          specs = if subspec_names.blank?
                    [spec]
                  else
                    subspec_names = [subspec_names] if subspec_names.is_a?(String)
                    subspec_names.map { |subspec_name| spec.subspec_by_name("#{spec.name}/#{subspec_name}") }
                  end

It will raise an error if :subspec=>123.

[amorde]

Yeah, I'd rather not just convert everything to a String since that becomes an expected functionality of the API

It makes sense that if you are specifying a subspec name, it should be a String.

[Whirlwind]

I add the type checking in the store_podspec method.

[amorde]

nit: remove the extra 'it'

[Whirlwind]

😂I just copy the description from last spec ( Line 402 ). Should I remove them?

[amorde]

just the beginning so it's it 'can use the dependencies of a podspec\'s subspec' do

[Whirlwind]

@amorde What description should I add into the changelog?

[amorde]

Something like

Add support for specifying subspecs when using the `podspec` Podfile attribute

[amorde]

@Whirlwind I think this is good to go! Could you squash the commits?

[dnkoutso]

+1 on squashing commits before we merge this

[Whirlwind]

@amorde @dnkoutso done. Thanks.

[amorde]

Thanks @Whirlwind!