Pre-install hook in the Tests podspec for local dev of gRPC-Core

1 files changed, 32 insertions, 0 deletions

diff --git a/src/objective-c/tests/Podfile b/src/objective-c/tests/Podfile
index f36c60c997..41814f18af 100644
--- a/src/objective-c/tests/Podfile
+++ b/src/objective-c/tests/Podfile
@@ -26,4 +26,36 @@ GRPC_LOCAL_SRC = '../../..'
   end
 end
 
+# gRPC-Core.podspec needs to be modified to be successfully used for local development. A Podfile's
+# pre_install hook lets us do that. The block passed to it runs after the podspecs are downloaded
+# and before they are installed in the user project.
+#
+# This podspec searches for the gRPC core library headers under "$(PODS_ROOT)/gRPC-Core", where
+# Cocoapods normally places the downloaded sources. When doing local development of the libraries,
+# though, Cocoapods just takes the sources from whatever directory was specified using `:path`, and
+# doesn't copy them under $(PODS_ROOT). When using static libraries, one can sometimes rely on the
+# symbolic links to the pods headers that Cocoapods creates under "$(PODS_ROOT)/Headers". But those
+# aren't created when using dynamic frameworks. So our solution is to modify the podspec on the fly
+# to point at the local directory where the sources are.
+#
+# TODO(jcanizales): Send a PR to Cocoapods to get rid of this need.
+pre_install do |installer|
+  # This is the gRPC-Core podspec object, as initialized by its podspec file.
+  grpc_core_spec = installer.pod_targets.find{|t| t.name == 'gRPC-Core'}.root_spec
+
+  # Copied from gRPC-Core.podspec, except for the adjusted src_root:
+
+  src_root = "$(PODS_ROOT)/../#{GRPC_LOCAL_SRC}"
+
+  public_build_settings = {
+    'GRPC_SRC_ROOT' => src_root,
+    'HEADER_SEARCH_PATHS' => '"$(inherited)" "$(GRPC_SRC_ROOT)/include"',
+  }
+  private_build_settings = public_build_settings.merge({
+    'USE_HEADERMAP' => 'NO',
+    'ALWAYS_SEARCH_USER_PATHS' => 'NO',
+    'USER_HEADER_SEARCH_PATHS' => '"$(GRPC_SRC_ROOT)"',
+  })
+  grpc_core_spec.user_target_xcconfig = public_build_settings
+  grpc_core_spec.pod_target_xcconfig = private_build_settings
 end