Emit More Comments in Xcode Project Files

[briantkelley]

Short description 📝

Update xcproj to support the comment property and to fix diff noise when creating plist entires for PBXVariantGroup, PBXProject, and PBXTarget.

Solution 📦

Add support for the comment property via a new PBXContainerItem class, which follows Xcode's design based on a Google class-dump header search. Update comment generation PBXVariantGroup, PBXProject, and PBXTarget to eliminate diff noise found when writing the 218 with xcproj.

Implementation 👩‍💻👨‍💻

• Add PBXContainerItem to support the comment property, matching the behavior from a class-dump search, and make it the super class of PBXBuildPhase and PBXTarget.
• When creating the comment fo PBXVariantGroup, fall back to path if name is nil.
• Similarly, when creating the comment for PBXProject.mainGroup and PBXProject.productRefGroup, fall back to path if name is nil.
• PBXTarget.buildRules emits the isa as the comment, similar to the dependencies property.

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This change is 

[pepicrft]

Shouldn't this be super.plistValues?

[briantkelley]

Yeah, I can update that to make it more clear. This method has an isa: named argument so this code isn't infinitely recursive. After reading your comment I was like, wait, how does this work? :)

[pepicrft]

Just a comment. Out of curiosity, how did you do the dump-header search that you mentioned?

[briantkelley]

I just searched around PBXTarget.h until I found something interesting. PBXContainerItem.h has the comments property, which PBXBuildPhase and PBXTarget inherit via the PBXProjectItem class.

[yonaskolb]

Where is the comment property set within the Xcode UI?

[briantkelley]

As far as I know, the UI for editing comments was eliminated in Xcode 4, but we still have a lot of comments throughout our 218 Xcode projects, so even though it's seemingly an obsolete feature, I'd like to eliminate diffs.