Add roots.pem bundle to the Bazel target, and use a better bundle name.

BUILD

@@ -1247,8 +1247,15 @@ objc_library(
     objc_client_path + "/private/*.m",
   ]),
   includes = [objc_path],
+  bundles = [":gRPCCertificates"],
   deps = [
     ":grpc_objc",
     ":rx_library",
   ],
 )
+
+objc_bundle_library(
+    # The choice of name is signicant here, since it determines the bundle name.
+    name = "gRPCCertificates",
+    resources = ["etc/roots.pem"],
+)

gRPC.podspec

@@ -520,7 +520,7 @@ Pod::Spec.new do |s|
     ss.dependency 'gRPC/RxLibrary'
 
     # Certificates, to be able to establish TLS connections:
-    ss.resource_bundles = { 'gRPC' => ['etc/roots.pem'] }
+    ss.resource_bundles = { 'gRPCCertificates' => ['etc/roots.pem'] }
   end
 
   # RPC library for ProtocolBuffers, based on gRPC

src/objective-c/GRPCClient/private/GRPCSecureChannel.m

@@ -43,8 +43,12 @@
   dispatch_once(&loading, ^{
     // Do not use NSBundle.mainBundle, as it's nil for tests of library projects.
     NSBundle *bundle = [NSBundle bundleForClass:self.class];
-    NSString *certsPath = [bundle pathForResource:@"gRPC.bundle/roots" ofType:@"pem"];
+    NSString *certsPath = [bundle pathForResource:@"gRPCCertificates.bundle/roots" ofType:@"pem"];
+    NSAssert(certsPath.length,
+             @"gRPCCertificates.bundle/roots.pem not found under %@. This file, with the root "
+             "certificates, is needed to establish TLS (HTTPS) connections.", bundle.bundlePath);
     NSData *certsData = [NSData dataWithContentsOfFile:certsPath];
+    NSAssert(certsData.length, @"No data read from %@", certsPath);
     NSString *certsString = [[NSString alloc] initWithData:certsData encoding:NSUTF8StringEncoding];
     kCredentials = grpc_ssl_credentials_create(certsString.UTF8String, NULL);
   });

templates/BUILD.template

@@ -193,8 +193,15 @@ objc_library(
     objc_client_path + "/private/*.m",
   ]),
   includes = [objc_path],
+  bundles = [":gRPCCertificates"],
   deps = [
     ":grpc_objc",
     ":rx_library",
   ],
 )
+
+objc_bundle_library(
+    # The choice of name is signicant here, since it determines the bundle name.
+    name = "gRPCCertificates",
+    resources = ["etc/roots.pem"],
+)

templates/gRPC.podspec.template

@@ -137,7 +137,7 @@ Pod::Spec.new do |s|
     ss.dependency 'gRPC/RxLibrary'
 
     # Certificates, to be able to establish TLS connections:
-    ss.resource_bundles = { 'gRPC' => ['etc/roots.pem'] }
+    ss.resource_bundles = { 'gRPCCertificates' => ['etc/roots.pem'] }
   end
 
   # RPC library for ProtocolBuffers, based on gRPC