Clever Geek Handbook

Contributing to Swift



Sound familiar?



Every time you tried to declare an optional closure @escapingin Swift, the compiler cursed and wrote an incomprehensible error @escaping attribute only applies to function types. I didn't like it and decided to fix it . Now the Swift 5.3 compiler will write instead of this error Closure is already escaping in optional type argument.



And today we will figure out how to contribute to the development of the Swift language.



What for



Swift β€” opensource-, , β€” . "contributed to Apple".





Swift macOS, Linux Windows, 15-70 GB Swift ( ).



Swift ++, , -, .





9 :



  1. bugs.swift.org.
  2. Swift.
  3. .
  4. .
  5. .
  6. .
  7. .
  8. .


.



bugs.swift.org



JIRA β€” , Issues .



Starter Bug- β€” , Swift. , .



Swift



Readme . , macOS, Linux Windows Swift .





brew install cmake ninja




brew bundle




mkdir swift-source
cd swift-source
git clone https://github.com/apple/swift.git #        
./swift/utils/update-checkout --clone


environment variable .



export SWIFT="~/swift-source"
export LLVM_SOURCE_ROOT="~/swift-source/llvm"




Swift β€” ninja Xcode.



Xcode , iOS IDE.



Ninja β€” C++ -, Xcode , IDE β€” Xcode. Swift ninja.



build-script β€” , LLDB Swift, SPM, ..



:



cd swift


ninja:



utils/build-script --release-debuginfo #


- , :



utils/build-script --release-debuginfo --debug-swift #   ,    
utils/build-script --release-debuginfo --debug-swift-stdlib # std  ,


Mac Pro, Swift :



: , + (~70 GB)



utils/build-script --debug


environment :



export SWIFT_BUILD_DIR="~/swift-source/build/Ninja-DebugAssert/swift-macosx-x86_64"


, ninja:



cd ${SWIFT_BUILD_DIR}
ninja swift


- , ninja swift.



Xcode



--xcode .



environment :



export XCODE_BUILD_DIR="~/swift-source/build/Xcode-DebugAssert/swift-macosx-x86_64"


.xcodeproj , 



open ${XCODE_BUILD_DIR}/Swift.xcodeproj


, Xcode .





swift Run. Swift, Xcode.



Xcode , .



swift, , .



P.S , , β€” forums.swift.org. .





β€” , .



, . , , . , Swift, , , , .



, , , Swift . Swift , , , , ..



.





Contributing to open source Swift by Jesse Squires



1) ( lib/Parse)



β€” AST ( ). β€” , . , , AST.



, / ..



2) (lib/Sema)



AST AST. .



3) Clang (lib/ClangImporter)



Clang C Objective-C API Swift API.



4) SIL (lib/SILGen)



Swift Intermediate Language (SIL) β€” , Swift . AST "" SIL.



5) SIL (lib/SILOptimizer/Mandatory)



, , . "" SIL.



6) SIL (lib/SILOptimizer)



, , ARC.



7) LLVM IR (lib/IRGen)



IR (Intermediate Representation) SIL LLVM IR, LLVM .



, , . :



  1. , .
  2. ( ), .
  3. , .


.





Swift :



  • TDD β€” , , , ( );
  • , Sema… TypeCheck… .


, .



Xcode Swift. , DiagnosticsSema.def escaping_non_function_parameter, , , NOTE, ERROR. 



// AST/DiagnosticsSema.def

ERROR(escaping_optional_type_argument, none,
       "closure is already escaping in optional type argument", ())


. , , .



// test/attr/attr_escaping.swift

func misuseEscaping(opt a: @escaping ((Int) -> Int)?) {} // expected-error{{closure is already escaping in optional type argument}} {{28-38=}}

func misuseEscaping(_ a: (@escaping (Int) -> Int)?) {} // expected-error{{closure is already escaping in optional type argument}} {{27-36=}}
func misuseEscaping(nest a: (((@escaping (Int) -> Int))?)) {} // expected-error{{closure is already escaping in optional type argument}} {{32-41=}}
func misuseEscaping(iuo a: (@escaping (Int) -> Int)!) {} // expected-error{{closure is already escaping in optional type argument}} {{29-38=}}


TypeCheckType.cpp, , , . , . , . , . , , , .



// *TypeCheckType.cpp*

const auto diagnoseInvalidAttr = [&](TypeAttrKind kind) {
  if (kind == TAK_escaping) {
    Type optionalObjectType = ty->getOptionalObjectType();
    if (optionalObjectType && optionalObjectType->is<AnyFunctionType>()) {
      return diagnoseInvalid(repr, attrs.getLoc(kind),
                             diag::escaping_optional_type_argument);
    }
  }
  return diagnoseInvalid(repr, attrs.getLoc(kind),
                         diag::attribute_requires_function_type,
                         TypeAttributes::getAttrName(kind));
};


TypeCheckType.cpp: if-, .



: C++ , clang-format, .



$SWIFT/clang/tools/clang-format/git-clang-format --force




Swift , . lit.py, cmake. .



lit.py, cheatsheet, . 



#   
${LLVM_SOURCE_ROOT}/utils/lit/lit.py ${SWIFT_BUILD_DIR}/test-macosx-x86_64/

#        
${LLVM_SOURCE_ROOT}/utils/lit/lit.py -sv ${SWIFT_BUILD_DIR}/test-macosx-x86_64/

#         
${LLVM_SOURCE_ROOT}/utils/lit/lit.py -a ${SWIFT_BUILD_DIR}/test-macosx-x86_64/attr/attr_escaping.swift}

#    
${LLVM_SOURCE_ROOT}/utils/lit/lit.py ${SWIFT_BUILD_DIR}/validation-test-macosx-x86_64/

#     ?   - ?
${LLVM_SOURCE_ROOT}/utils/lit/lit.py ${SWIFT_BUILD_DIR}/test-macosx-x86_64/ --filter=<REGEX>


: lit --filter .





, , .



, squash , . , . : fix-it-for-removing-escaping-from-optional-closure-parameter.





Swift , . , ++ . , , .





, .







opensource- Swift , .



, , . Starter Task- Swift!







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