Weaken the dependency on XCTest #146

briancroom · 2015-07-10T12:24:41Z

I had some good success working on what seems like a great solution to #144. The weak linking seems to be working successfully. The process dies with a dylib error the instant that you try to instantiate NimbleXCTestHandler without the XCTest framework+lib around, so I added some code to prevent that form happening. We could potentially try to add a non-crashing fallback assertion handler for this situation as well.

Thoughts? @jeffh @tjarratt

tjarratt · 2015-07-10T17:53:11Z

This is really awesome! It looks like the build failed because CircleCI doesn't support the latest swift compiler (but I'm not 100% sure).

briancroom · 2015-07-11T15:03:15Z

Would it make sense to apply this to a different branch (master?) instead?

jeffh · 2015-07-12T08:14:51Z

Don't worry about CircleCI, it doesn't support Swift 2.0 yet, so it's always red for the swift-2.0 branch. I manually run the tests before merging in PRs. The master branch is for stable swift (1.2).

Hey @briancroom, are you doing something special to get Nimble working without XCTest? I've tried importing Nimble as an app dependency in a demo app as an example (using carthage or cocoapods), but it doesn't work. libswiftXCTest is still required.

$ otool -L /Users/jeff/Library/Developer/Xcode/DerivedData/Nimble-ejlspkozrikyvdavdrwfoyknlvax/Build/Products/Debug-iphoneos/Nimble.framework/Nimble
/Users/jeff/Library/Developer/Xcode/DerivedData/Nimble-ejlspkozrikyvdavdrwfoyknlvax/Build/Products/Debug-iphoneos/Nimble.framework/Nimble (architecture armv7):
    @rpath/Nimble.framework/Nimble (compatibility version 1.0.0, current version 1.0.0)
    @rpath/libswiftXCTest.dylib (compatibility version 0.0.0, current version 0.0.0)
    /System/Library/Frameworks/Foundation.framework/Foundation (compatibility version 300.0.0, current version 1223.1.0)
    /usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 228.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1223.0.0)
    /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation (compatibility version 150.0.0, current version 1223.1.0)
    @rpath/libswiftCore.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftCoreGraphics.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftCoreImage.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftDarwin.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftDispatch.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftFoundation.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftObjectiveC.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftSecurity.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftUIKit.dylib (compatibility version 0.0.0, current version 0.0.0)
/Users/jeff/Library/Developer/Xcode/DerivedData/Nimble-ejlspkozrikyvdavdrwfoyknlvax/Build/Products/Debug-iphoneos/Nimble.framework/Nimble (architecture arm64):
    @rpath/Nimble.framework/Nimble (compatibility version 1.0.0, current version 1.0.0)
    @rpath/libswiftXCTest.dylib (compatibility version 0.0.0, current version 0.0.0)
    /System/Library/Frameworks/Foundation.framework/Foundation (compatibility version 300.0.0, current version 1223.1.0)
    /usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 228.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1223.0.0)
    /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation (compatibility version 150.0.0, current version 1223.1.0)
    @rpath/libswiftCore.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftCoreGraphics.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftCoreImage.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftDarwin.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftDispatch.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftFoundation.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftObjectiveC.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftSecurity.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libswiftUIKit.dylib (compatibility version 0.0.0, current version 0.0.0)

briancroom · 2015-07-15T02:37:22Z

That's interesting, @jeffh, I hadn't tried running inspecting the Nimble binary with otool. I've done some more digging, and it seems that the -L command reports linked dylibs without any indication of whether they are weakly referenced or not, however if you use -l to get the list of load commands, then you can see the distinction:

...
Load command 10
          cmd LC_LOAD_WEAK_DYLIB
      cmdsize 72
         name @rpath/XCTest.framework/Versions/A/XCTest (offset 24)
   time stamp 2 Wed Dec 31 19:00:02 1969
      current version 8131.5.0
compatibility version 1.0.0
Load command 11
          cmd LC_LOAD_WEAK_DYLIB
      cmdsize 56
         name @rpath/libswiftXCTest.dylib (offset 24)
   time stamp 2 Wed Dec 31 19:00:02 1969
      current version 0.0.0
compatibility version 0.0.0
Load command 12
          cmd LC_LOAD_DYLIB
      cmdsize 96
         name /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation (offset 24)
   time stamp 2 Wed Dec 31 19:00:02 1969
      current version 1223.1.0
compatibility version 300.0.0
...

I have also pushed a branch that shows an example of using Nimble without XCTest to briancroom/Nimble@0d3721f

To be fair, I haven't attempted this with pulling in the framework via Cocoapods or Carthage yet. I'm anticipating that Carthage will work, but it may take some additional work to get Cocoapods to build it correctly.

briancroom · 2015-07-15T03:50:17Z

Ah, I see...there's more going on here than I realized. The example app I linked to was included in the Nimble workspace. It links with a copy of the Nimble framework that isn't embedded in the final app, which meant that swift-stdlib-tool didn't scan Nimble when it decides which Swift libraries to copy in.

I tested it with Carthage now and encountered the same problem that @jeffh saw, presumably. swift-stdlib-tool copies libswiftXCTest.dylib into the app bundle, because it sees that Nimble can take advantage of it, but then the app crashes on launch because that dylib is strongly linked to XCTest.framework. I tried adding a Run Script to delete libswiftXCTest.dylib, but the Swift libs aren't copied until after the script executes.

I'm going to need to experiment a bit more to determine what other approaches may be feasible to work around this.

briancroom · 2015-07-17T17:20:39Z

A couple more findings...

When using this with Carthage, the app will launch and execute as expected if I manually delete libswiftXCTest.dylib from the app bundle after Xcode finishes making the build, however I haven't been able to figure out a way to make this work as part of a standard Xcode Run action
I'm intending to file a Radar on swift-stdlib-tool asking for more flexible handling of weakly linked libraries, or some other way to modify the handling of the XCTest support lib
Because of these issues, I've lost a lot of confidence in using weak linking as a solution to Using Nimble without XCTest #144, unfortunately

briancroom · 2015-08-06T18:21:22Z

A couple updates:

I rebased this against the latest on the swift-2.0 branch
I was able to get this working for iOS and Mac apps using Nimble as a Carthage-built framework by adding a post-build scheme action running a script[1] that deletes the copy of libswiftXCTest.dylib that swift-stdlib-tool copies into the bundle. This would only be a requirement for people trying to use Nimble without XCTest.
This patch set seems to me to align with @modocache's stated goal of trying to loosen Quick's coupling with XCTest.

[1]

rm "${SWIFT_STDLIB_TOOL_DESTINATION_DIR}/libswiftXCTest.dylib"

briancroom · 2015-08-07T03:07:27Z

@jeffh I've pushed a usage example of this: https://github.com/briancroom/NimbleWithCarthageExample

jeffh · 2015-08-13T04:26:41Z

Hey @briancroom, would this script be safe to run in always or does this cause surprising failures when XCTest should automatically be linked, but isn't? I'm wondering if this is something more automatic or documentation that needs to mention how to run Nimble without XCTest.

Sorry, I haven't been spending significant time on Nimble since it's annoying that Xcode 7 beta 5 crashes on Nimble's test suite.

briancroom · 2015-08-14T04:35:43Z

Thanks for bringing up documentation @jeffh. I've added a section to the README indicating how this works.

modocache · 2015-08-15T16:04:28Z

This is really cool! 👍

Code looks good to me, but I'll defer to @jeffh to merge. If this is the direction Nimble is taking, I'd love to explore whether Quick could also use weak linking.

jeffh · 2015-08-17T16:21:36Z

Hey @briancroom,

In Xcode 7 beta 5, it doesn't seem like 'SWIFT_STDLIB_TOOL_DESTINATION_DIR' exists?

briancroom · 2015-08-18T16:38:23Z

@jeffh I just gave it another try on beta 5 and it seemed to be working. If the script isn't finding the environment variable, maybe check to make sure that you selected the right target in the script's "Provide build settings from" dropdown? When working on this, I was putting the following line in the script to see what I had available:

export > /tmp/out.txt

Do you see the expected build settings env vars from that?

jeffh · 2015-08-26T08:37:14Z

Oh never mind, I configured it incorrectly. My bad. But I still seem to get failure when running. This could be because I'm now running Xcode 7 beta 6.

Sorry for the long turnaround. I've also uploaded my repo that I've been using to test: https://github.com/jeffh/NimbleCocoaPodsExample.

I'll raise this issue to a higher priority so I can respond more regularly.

This allows using Nimble without pulling XCTest into your process.

…est is not available

When strongly linking XCTest, Cocoapods automatically adds a framework search path to allow the framework to be found. When weakly linking, it must be manually specified.

briancroom · 2015-09-02T17:56:36Z

Hey @jeffh , thanks for that repo. That was useful for testing just now. I just found some time to get this rebased to include the new commits on the swift-2.0 branch. After doing so, I was able to get your example repo working by using the following Podfile:

platform :ios, '8.0'

use_frameworks!

target 'NimbleCocoaPodsExample' do
  pod 'Nimble', :path => '../TestingTools/Nimble' #:git => 'https://github.com/briancroom/Nimble', :branch => 'weakly-link-xctest'
end

target 'NimbleCocoaPodsExampleTests' do
  pod 'Quick', :git => 'https://github.com/Quick/Quick', :tag => 'v0.6.0'
  pod 'Nimble', :path => '../TestingTools/Nimble' #:git => 'https://github.com/briancroom/Nimble', :branch => 'weakly-link-xctest'
end

When you get a few minutes, could you take another look?

jeffh · 2015-09-03T15:53:06Z

I'll take a look tonight. Thanks.

—
Sent from my iPhone

On Wed, Sep 2, 2015 at 10:56 AM, Brian Croom notifications@github.com
wrote:

Hey Jeff, thanks for that repo. That was useful for testing just now. I just found some time to get this rebased to include the new commits on the swift-2.0 branch. After doing so, I was able to get your example repo working by using the following Podfile:
platform :ios, '8.0'
use_frameworks!
target 'NimbleCocoaPodsExample' do
  pod 'Nimble', :path => '../TestingTools/Nimble' #:git => 'https://github.com/briancroom/Nimble', :branch => 'weakly-link-xctest'
end
target 'NimbleCocoaPodsExampleTests' do
  pod 'Quick', :git => 'https://github.com/Quick/Quick', :tag => 'v0.6.0'
  pod 'Nimble', :path => '../TestingTools/Nimble' #:git => 'https://github.com/briancroom/Nimble', :branch => 'weakly-link-xctest'
end
When you get a few minutes, could you take another look?

Reply to this email directly or view it on GitHub:
#146 (comment)

Weaken the dependency on XCTest

jeffh · 2015-09-07T09:29:49Z

Thanks @briancroom, I've gotten it to work. Although, I'm not sure if it was cache cleaning, cocoapods update, or xcode update that's related to the original issues i've been having.

briancroom · 2015-09-08T23:56:16Z

🎉 Thanks @jeffh for seeing this through! Also to @tjarratt for the initial inspiration.

Weaken the dependency on XCTest

briancroom force-pushed the weakly-link-xctest branch from cbaeedf to d2b4eba Compare August 6, 2015 17:40

modocache mentioned this pull request Aug 15, 2015

Using Nimble without XCTest #144

Closed

jeffh added the high priority label Aug 26, 2015

Brian Croom added 4 commits September 2, 2015 13:33

Weakly link to the XCTest framework and the XCTest Swift support library

3471c07

This allows using Nimble without pulling XCTest into your process.

Emit a somewhat more informative error message before aborting if XCT…

2ad3f1f

…est is not available

Update the podspec to weakly link XCTest

4e6b23e

When strongly linking XCTest, Cocoapods automatically adds a framework search path to allow the framework to be found. When weakly linking, it must be manually specified.

Document how to use Nimble without XCTest

9cba9f1

briancroom force-pushed the weakly-link-xctest branch from 89fba37 to 9cba9f1 Compare September 2, 2015 17:33

Fix overridden project config in the podspec

0fc8ada

jeffh added a commit that referenced this pull request Sep 7, 2015

Merge pull request #146 from briancroom/weakly-link-xctest

8baefcc

Weaken the dependency on XCTest

jeffh merged commit 8baefcc into Quick:swift-2.0 Sep 7, 2015

briancroom deleted the weakly-link-xctest branch January 20, 2016 18:37

Megal pushed a commit to Megal/Nimble that referenced this pull request Jul 31, 2019

Merge pull request Quick#146 from briancroom/weakly-link-xctest

5b67696

Weaken the dependency on XCTest

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Weaken the dependency on XCTest #146

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When you get a few minutes, could you take another look?

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briancroom commented Sep 8, 2015

Weaken the dependency on XCTest #146

Weaken the dependency on XCTest #146

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When you get a few minutes, could you take another look?

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