[msbuild] Always codesign the framework directory, not what's inside

[spouliot]

Example #1. Signing a framework binary is the same thing as
signing the framework directory.

$ codesign -v --force --timestamp=none --sign - bin/iPhone/Release/xcf_ios.app//Frameworks/lame.framework/lame
bin/iPhone/Release/xcf_ios.app//Frameworks/lame.framework/lame: replacing existing signature
bin/iPhone/Release/xcf_ios.app//Frameworks/lame.framework/lame: signed bundle with Mach-O thin (arm64) [io.sourceforge.lame]

$ codesign -v --force --timestamp=none --sign - bin/iPhone/Release/xcf_ios.app//Frameworks/lame.framework
bin/iPhone/Release/xcf_ios.app//Frameworks/lame.framework: replacing existing signature
bin/iPhone/Release/xcf_ios.app//Frameworks/lame.framework: signed bundle with Mach-O thin (arm64) [io.sourceforge.lame]

Nice right ? Pretty much until...

Example #2. Signing a framework binary is NOT the same thing
as signing the framework directory.

$ codesign -v --force --timestamp=none --sign - bin/iPhone/Release/xcf_ios.app//Frameworks/flac.framework/flac
bin/iPhone/Release/xcf_ios.app//Frameworks/flac.framework/flac: replacing existing signature
bin/iPhone/Release/xcf_ios.app//Frameworks/flac.framework/flac: signed Mach-O thin (arm64) [flac-55554944583d2f02282c33d8bfed082daa857e30]

$ codesign -v --force --timestamp=none --sign - bin/iPhone/Release/xcf_ios.app//Frameworks/flac.framework
bin/iPhone/Release/xcf_ios.app//Frameworks/flac.framework: replacing existing signature
bin/iPhone/Release/xcf_ios.app//Frameworks/flac.framework: signed bundle with Mach-O thin (arm64) [org.xiph.flac]

In this case signing the binary flac does not produce the
_CodeSignature directory and fails our msbuild Codesign task

The fix is to detect if we're signing a framework like A.framework/A
and change this to sign A.framework as this will always work.

[dalexsoto]

Because it all makes sense and it is so straightforward 😂

[vs-mobiletools-engineering-service2]

❌ Device tests failed on Build ❌

Device tests failed on Build.

• Azure DevOps
• Html Report (VSDrops)

Test results

2 tests failed, 39 tests passed.

Failed tests

• [xUnit] Mono Mac OS X BCL tests group 4/Mac Modern/Debug: Failed (No test log file was produced)
• MTouch tests/NUnit: Failed (Execution failed with exit code 7)

Pipeline on Agent XAMBOT-1094'

[monojenkins]

Build failure
✅ Provisioning succeeded
✅ Build succeeded
✅ API Diff (from stable)
🔥 Failed to compare API and create generator diff 🔥
    ** Error: Working directory isn't clean:
    HEAD detached at 9b7fd9f
    Untracked files:
    (use "git add ..." to include in what will be committed)
    tools/dotnet-linker/packages/
    
    nothing added to commit but untracked files present (use "git add" to track)
    Search for Comparing API & creating generator diff in the log to view the complete log.
✅ Test run succeeded