Unknown type name 'namespace' in umbrella-header.h that include cpp headers

[Alexufo]

I am trying to compile a swift project with my pod. My pod contains binary libs and c++ wrapper for them.
I have successfully created the pod for the default objc project and everything works fine.

Then I try to integrate my pod into the default swift project in the same way and I get

I remove "import myModule" from swift (the project starts compiling without errors) and put bridge-header.h. After that I can access my pod, but I don't want to use bridge-header.h Is it possible?

[ospfranco]

Did you find a solution for this?

[Alexufo]

Did you find a solution for this?

No. I use bridge-header in parent project. A bit hacky.

 s.xcconfig = { "SWIFT_OBJC_BRIDGING_HEADER" => "${PODS_CONFIGURATION_BUILD_DIR}/Name/Name.framework/Headers/Name-Bridging-Header.h"}

Bridge header will be avalable in xcode after first build.

[ospfranco]

The root issue is Swift compiler fault, it doesn't support C++. Whenever you have Swift files together with C++ files, it's the Swift compiler that will kick-in and will try to compile the headers as C headers independently of what you tell it, file extensions, etc. Here is the workaround I found:

require "json"

package = JSON.parse(File.read(File.join(__dir__, "package.json")))

Pod::Spec.new do |s|
  s.name           = "matrix"
  s.version        = package["version"]
  s.summary        = package["description"]
  s.homepage       = package["homepage"]
  s.license        = package["license"]
  s.authors        = package["author"]
  s.platforms      = { :ios => "13.0" }

  s.pod_target_xcconfig = {
    "DEFINES_MODULE" => "YES",
    "SWIFT_COMPILATION_MODE" => "wholemodule",
    "CLANG_CXX_LANGUAGE_STANDARD" => "c++17",
    "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)/cpp/\"/** " # This will link the headers at compile time, flag passed directly to the compiler
  }

  s.source_files = "ios/**/*.{mm,swift}", "cpp/**/*.{cpp,c}" # Do not include the headers in the sources, then XCode won't try to compile them

  s.preserve_paths = [
    "cpp/**/*.h",
    "ios/**/*.h"
  ]
  
  s.dependency "React"
  s.dependency "React-Core"
  s.dependency "React-callinvoker"
end

By not including the headers in source_files XCode does not try to compile them, but by adding them to the HEADER_SEARCH_PATHS they are still found on the linking step of the compilation.

One side effect is that the headers will not appear on the project explorer view on XCode which is annoying if you are developing something from scratch but I don't see any other workaround.

The other alternative would be as stated in the Stack Overflow answer, to hide everything with macros that check if C++ is compiling the header.

It does not solve the problem the generated umbrella header does not check for this, which CocoaPods can better handle.

[Alexufo]

Thanks. I left PODS_CONFIGURATION_BUILD_DIR.

My working pod is

Pod::Spec.new do |s|
  s.name             = 'Id'
  s.version          = '0.1.0'
  s.summary          = 'Swift pod'
  s.homepage         = 'https://'

  s.source           = { :path => './' }
  
  s.ios.deployment_target = '11.0'
  s.frameworks = 'UIKit', 'Foundation','AVFoundation' , 'CoreVideo', 'CoreGraphics', 'CoreMedia'
  
  s.ios.resources = 'Core/data'
  s.ios.vendored_frameworks = 'Core/lib/*.xcframework'
  
  s.xcconfig = {
    'SWIFT_OBJC_BRIDGING_HEADER' => '$(PODS_ROOT)/../S/S-Bridging-Header.h',
    'HEADER_SEARCH_PATHS' =>
    '$(PODS_ROOT)/../Core/wrap/objcs/include ' +
    '$(PODS_ROOT)/../Core/wrap/objcs/include_impl ' +
    '$(PODS_ROOT)/../Core/wrap/objci/include ' +
    '$(PODS_ROOT)/../Core/wrap/objci/include_impl ' +
    '$(PODS_ROOT)/../Core/include'
  }

  s.pod_target_xcconfig = {  
    "DEFINES_MODULE" => "YES",
    'ENABLE_BITCODE' => "NO",
    'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'i386'
  }
  
  s.subspec 'Core' do |h|
    h.source_files =  "Core/wrap/**/*.{mm,h}", "Core/include/**/*.{mm,h}"
    h.header_mappings_dir = './'
  end
  
  s.subspec 'S' do |w|
    w.source_files =  "S/**/*.{mm,h}"
  end
  
end

preserve_paths doesn't work for me. If I ignore the *.h, they won't be copied to the build folder. If I move xcconfig to pod_target_xcconfig, I get the problem I wrote about earlier