Reuse ReferenceProxy references when possible

[OdNairy]

XcodeGen should reuse PBXReferenceProxy for external targets when possible. In the current state, Xcode will remove all duplicated dependencies as soon as any change in pbxproj happens.

https://user-images.githubusercontent.com/735178/235425213-eba0bdda-8caf-4b14-9f4a-7244ddb7c030.mov

[OdNairy]

@yonaskolb Is there anything I can do to help you to review this PR?

[antonyalkmim]

Thanks for this fix @OdNairy 👏.

I'm facing a problem using targetTemplates that I think this PR solves. Unfortunately I cant run some targets because the dependencies are not being imported on some targets that uses the same template. Clone and run xcodegen locally solves my problem.

@yonaskolb are you waiting for more PRs to add on next release or there is a release date? Can you release this fix for us? 😅

[liamnichols]

I was currently investigating something similar to #1339 in my project file and I wanted to test with the latest master to try and dig into the issue, but I think something in this commit might have added to the problem.

Prior to this change, I had one unused object reference for a PBXGroup that I was investigating, but now there are a lot of unused PBXContainerItemProxy references in the generated project file:

(R.swift has a linting tool that is picking this up for me)

The references seem to be related to targets from a different Xcode project of mine:

TofuClient, XCTestKit, APIKit, ImageKit etc are all targets in a referenced project called Frameworks.xcodeproj

Perhaps the missing piece here is that we're still creating new PBXContainerItemProxy objects when we reuse the PBXReferenceProxy which is leading to the orphaned object?

[liamnichols]

Ah yes, further up in the file, we're always adding the container item when we create it:

https://github.com/yonaskolb/XcodeGen/blob/af1adfe1cddaac0fc6be0ad50b79f6227900fa18/Sources/XcodeGenKit/PBXProjGenerator.swift#L410-L417

But really I think that we need to do something like this:

diff --git a/Sources/XcodeGenKit/PBXProjGenerator.swift b/Sources/XcodeGenKit/PBXProjGenerator.swift
index 6e77c3f..9ad0c91 100644
--- a/Sources/XcodeGenKit/PBXProjGenerator.swift
+++ b/Sources/XcodeGenKit/PBXProjGenerator.swift
@@ -407,13 +407,11 @@ public class PBXProjGenerator {
             )
         )

-        let productProxy = addObject(
-            PBXContainerItemProxy(
-                containerPortal: .fileReference(projectFileReference),
-                remoteGlobalID: targetObject.product.flatMap(PBXContainerItemProxy.RemoteGlobalID.object),
-                proxyType: .reference,
-                remoteInfo: target
-            )
+        let productProxy = PBXContainerItemProxy(
+            containerPortal: .fileReference(projectFileReference),
+            remoteGlobalID: targetObject.product.flatMap(PBXContainerItemProxy.RemoteGlobalID.object),
+            proxyType: .reference,
+            remoteInfo: target
         )

         var path = targetObject.productNameWithExtension()
@@ -437,6 +435,7 @@ public class PBXProjGenerator {
         if let existingValue = existingValue {
             productReferenceProxy = existingValue
         } else {
+            addObject(productProxy)
             productReferenceProxy = addObject(
                 PBXReferenceProxy(
                     fileType: productReferenceProxyFileType,

It fixed the issue in my project file, but I need to run through and see if there is more to it than that or not.

[yonaskolb]

@liamnichols would you mind opening a PR for this?