[PodTargetInstaller] Dont set clang-specific flags for files that wont be compiled with clang

CHANGELOG.md

@@ -47,6 +47,11 @@ To install release candidates run `[sudo] gem install cocoapods --pre`
   [Samuel Giddins](https://github.com/segiddins)
   [#3436](https://github.com/CocoaPods/CocoaPods/issues/3436)
 
+* Don't set the `-fno-objc-arc` compiler flags for files for which the flag
+  makes no sense.  
+  [Samuel Giddins](https://github.com/segiddins)
+  [#2559](https://github.com/CocoaPods/CocoaPods/issues/2559)
+
 
 ## 0.37.0.beta.1
 

lib/cocoapods/installer/target_installer/pod_target_installer.rb

@@ -38,6 +38,8 @@ module Pod
 
       #-----------------------------------------------------------------------#
 
+      SOURCE_FILE_EXTENSIONS = Sandbox::FileAccessor::SOURCE_FILE_EXTENSIONS
+
       # Adds the build files of the pods to the target and adds a reference to
       # the frameworks of the Pods.
       #
@@ -53,7 +55,7 @@ module Pod
           headers = file_accessor.headers
           public_headers = file_accessor.public_headers
           private_headers = file_accessor.private_headers
-          other_source_files = file_accessor.source_files.select { |sf| sf.extname == '.d' }
+          other_source_files = file_accessor.source_files.reject { |sf| SOURCE_FILE_EXTENSIONS.include?(sf.extname) }
 
           {
             true => file_accessor.arc_source_files,

lib/cocoapods/sandbox/file_accessor.rb

@@ -8,11 +8,12 @@ module Pod
     #
     class FileAccessor
       HEADER_EXTENSIONS = Xcodeproj::Constants::HEADER_FILES_EXTENSIONS
+      SOURCE_FILE_EXTENSIONS = (%w(.m .mm .c .cpp .swift) + HEADER_EXTENSIONS).uniq.freeze
 
       GLOB_PATTERNS = {
         :readme              => 'readme{*,.*}'.freeze,
         :license             => 'licen{c,s}e{*,.*}'.freeze,
-        :source_files        => '*.{h,hpp,tpp,hh,m,mm,c,cpp,swift}'.freeze,
+        :source_files        => "*{#{SOURCE_FILE_EXTENSIONS.join(',')}}".freeze,
         :public_header_files => "*{#{HEADER_EXTENSIONS.join(',')}}".freeze,
       }.freeze
 

spec/unit/sandbox/file_accessor_spec.rb

@@ -211,7 +211,7 @@ module Pod
           file_patterns = ['Classes/*.{h,m,d}', 'Vendor']
           options = {
             :exclude_patterns => ['Classes/**/osx/**/*', 'Resources/**/osx/**/*'],
-            :dir_pattern => '*.{h,hpp,tpp,hh,m,mm,c,cpp,swift}',
+            :dir_pattern => '*{.m,.mm,.c,.cpp,.swift,.h,.hh,.hpp,.ipp,.tpp}',
             :include_dirs => false,
           }
           @spec.exclude_files = options[:exclude_patterns]