问题
My project always runs correctly on all devices using Xcode 11, but after I installed Xcode 12 beta 4, it is failing to build on the simulator.
I compared the build logs of Xcode 11 and Xcode 12 and it seems in Xcode 12 that my main target is being built before the cocoa pods target, and so the link will fail because the cocoapods library will not be found.
How to fix the order of the build target?
In Xcode 11, everything is fine. My own target is built after the cocoapods target .
In Xcode 12, the build is out of order My own target is built before the cocoapods target .
回答1:
OK, i got a solution to make the build work (this way to fix problem is not correct , the right way to fix is added in my update):
1 you need to add the Pods project to your main project as a external project
2 add all the cocodpods target as dependency explicitly in your main project 's build phase
But i still think may be the new beta version of xcode 12 will fix this. because it seem a bug of xcode 12 (my project work perfect in xcode 11 and xcode 12 + ios device , failed in xcode 12 + simulator only)
###2020-08-17 update###
i found a more exactly reason to reproduce this problem , it seems my project file open in xcode 12 will auto generate a VALID_ARCHS macro in User-Defines , and this macro will make the build failed
And i found that ,with this macro , During in the LINK of building,the link target type will be a unknown type 'arm64-apple-ios11.0-simulator' which cause the build faild and the problem that all the targets build in wrong order seems will only happen when this macro is being added
XcodeDefault.xctoolchain/usr/bin/clang -target arm64-apple-ios11.0-simulator
after i delete this VALID_ARCHS macro, the link target type will be 'x86_64-apple-ios11.0-simulator' , and everything goes well
XcodeDefault.xctoolchain/usr/bin/clang -target x86_64-apple-ios11.0-simulator
####2020-09-11 add Add Apple's Feedback about this macro####
update Apple's Feedback on VALID_ARCHSAfter reviewing your feedback, we have some additional information for you:
Xcode does not add VALID_ARCHS to your project. Indeed, we recommend against using VALID_ARCHS. Maybe some CocoaPod is setting it in your project for some reason? CocoaPods are not part of Xcode so, we don’t have any control over what they do.
One thing to note is that in Xcode 11 VALID_ARCHS showed up under the architectures section. Since we are strongly recommending against using it, it no longer shows up there and now appears in the User Defined section if it is defined at all.
Xcode 11 used to automatically translate building for arm64 for the simulator into building for x86_64, but now that arm64 is a valid simulator architecture (it’s the Apple Silicon architecture), that translation no longer occurs.
So, we suspect what you should do is delete VALID_ARCHS from your project altogether, and make sure Architectures (ARCHS) is set to Standard Architectures (ARCHS_STANDARD) and not to something specific (unless you really know exactly why you’re not using ARCHS_STANDARD).
####Feedback end####
####2020-10-10 added####
the build may still not working after deleting the VALID_ARCHS macro for some guys , you may check the answer of Apple's feedback added and @Andrei Herford's answer below:
make sure Architectures (ARCHS) is set to Standard Architectures (ARCHS_STANDARD)
and then delete the macro ,hope these two steps works for all:)
####2020-10-10 added end####
回答2:
I was able to solve the problem both in simulator and on device by using $(ARCHS_STANDARD) not only for ARCHS in the Architecture settings but also in VALID_ARCHS as well. I am not sure what possible side effect changing the archs in this way might have but so far I have not experiencend any new problems.
Details:
The excellent answer by @ximmyxiao got me on the right track. However, the solution proposend by him (remove VALID_ARCHS) did not work for me. This led to a new problem when compiling the Pod targets (Command PhaseScriptExecution failed with a nonzero exit code and ARCHS[@]: unbound variable in Pods script).
Instead replacing arm64 with x86_64in VALID_ARCHS solved the problem when building for simulator. It seems that arm64 was never a correct platform and was translated to x86 by Xcode. As Apple has announced their shift to ARM processors, this translation is not correct anymore and thus one has to use the the correct platform x86_64 instead.
Regarding to Apple VALID_ARCHS should not be used any more. However, this fix did not work when building for devices. Eventually using $(ARCHS_STANDARD) instead (both for simulator and device) did the trick in both cases.
Good look to others who encounter this kind of problems. Never gets boring working with Xcode....
回答3:
For Xcode Version 12.1 If you can't find VALID_ARCHS Adding **$(ARCHS_STANDARD) x86_64 i386 all three in Architectures will solve the issue for running on simulators and Devices , archiving . also suggestedly add Build Active Architecture Only to 'Yes'.
来源：https://stackoverflow.com/questions/63391793/xcode-12-build-target-in-wrong-order-for-simulator