Migrate Firebase off ObjC module @import statements (#992)

* Migrate Firebase off @import statements

* - Migrate tests and test utils from @import to #import.
  - Update Xcode projects for tests to explicitly link in framework deps.
  - Update check_no_module_imports.sh to look for @imports in tests/test utils/
    integration tests.

* Ensure check_no_module_imports.sh explicitly exits with code 0 on success.

26 files changed, 86 insertions, 26 deletions

diff --git a/.travis.yml b/.travis.yml
index c907873..d68fafc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,6 +17,7 @@ jobs:
       script:
         - ./scripts/check_whitespace.sh
         - ./scripts/check_copyright.sh
+        - ./scripts/check_no_module_imports.sh
         - ./scripts/style.sh test-only $TRAVIS_COMMIT_RANGE
         # Google C++ style compliance
         - ./scripts/lint.sh $TRAVIS_COMMIT_RANGE
diff --git a/Example/Auth/Tests/FIRPhoneAuthProviderTests.m b/Example/Auth/Tests/FIRPhoneAuthProviderTests.m
index 0dc0b44..2b58270 100644
--- a/Example/Auth/Tests/FIRPhoneAuthProviderTests.m
+++ b/Example/Auth/Tests/FIRPhoneAuthProviderTests.m
@@ -44,7 +44,7 @@
 #import "OCMStubRecorder+FIRAuthUnitTests.h"
 #import "Phone/FIRPhoneAuthCredential_Internal.h"
 
-@import SafariServices;
+#import <SafariServices/SafariServices.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
diff --git a/Example/Firebase.xcodeproj/project.pbxproj b/Example/Firebase.xcodeproj/project.pbxproj
index 57fbfc9..5b887a9 100644
--- a/Example/Firebase.xcodeproj/project.pbxproj
+++ b/Example/Firebase.xcodeproj/project.pbxproj
@@ -120,6 +120,11 @@
 		7EE21F7A1FE89193009B1370 /* FIREmailLinkRequestTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 7EE21F791FE89193009B1370 /* FIREmailLinkRequestTests.m */; };
 		7EE21F7C1FE8919E009B1370 /* FIREmailLinkSignInResponseTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 7EE21F7B1FE8919D009B1370 /* FIREmailLinkSignInResponseTests.m */; };
 		7EFA2E041F71C93300DD354F /* FIRUserMetadataTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 7EFA2E031F71C93300DD354F /* FIRUserMetadataTests.m */; };
+		923F824C206C4D8000034974 /* SafariServices.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 923F824B206C4D8000034974 /* SafariServices.framework */; };
+		923F824E206C4D8B00034974 /* SafariServices.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 923F824D206C4D8B00034974 /* SafariServices.framework */; };
+		923F824F206C4DA500034974 /* XCTest.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = DE45C6641E7DA8CB009E6ACD /* XCTest.framework */; };
+		923F8251206C4DC600034974 /* UserNotifications.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 923F8250206C4DC500034974 /* UserNotifications.framework */; settings = {ATTRIBUTES = (Weak, ); }; };
+		923F8252206C4DD500034974 /* UIKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F591195388D20070C39A /* UIKit.framework */; };
 		AFAF36F51EC28C25004BDEE5 /* Shared.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = AFAF36F41EC28C25004BDEE5 /* Shared.xcassets */; };
 		AFAF36F61EC28C25004BDEE5 /* Shared.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = AFAF36F41EC28C25004BDEE5 /* Shared.xcassets */; };
 		AFAF36F71EC28C25004BDEE5 /* Shared.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = AFAF36F41EC28C25004BDEE5 /* Shared.xcassets */; };
@@ -951,6 +956,9 @@
 		7EE21F7B1FE8919D009B1370 /* FIREmailLinkSignInResponseTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = FIREmailLinkSignInResponseTests.m; sourceTree = "<group>"; };
 		7EFA2E031F71C93300DD354F /* FIRUserMetadataTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = FIRUserMetadataTests.m; sourceTree = "<group>"; };
 		8496034D8156555C5FCF8F14 /* README.md */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = net.daringfireball.markdown; name = README.md; path = ../README.md; sourceTree = "<group>"; };
+		923F824B206C4D8000034974 /* SafariServices.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = SafariServices.framework; path = System/Library/Frameworks/SafariServices.framework; sourceTree = SDKROOT; };
+		923F824D206C4D8B00034974 /* SafariServices.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = SafariServices.framework; path = Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk/System/Library/Frameworks/SafariServices.framework; sourceTree = DEVELOPER_DIR; };
+		923F8250206C4DC500034974 /* UserNotifications.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = UserNotifications.framework; path = System/Library/Frameworks/UserNotifications.framework; sourceTree = SDKROOT; };
 		AFAF36F41EC28C25004BDEE5 /* Shared.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; name = Shared.xcassets; path = Shared/Shared.xcassets; sourceTree = "<group>"; };
 		AFC8BA9C1EBD230E00B8EEAE /* NotificationsController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = NotificationsController.swift; sourceTree = "<group>"; };
 		AFC8BA9E1EBD51A700B8EEAE /* Environment.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Environment.swift; sourceTree = "<group>"; };
@@ -1316,6 +1324,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				923F824E206C4D8B00034974 /* SafariServices.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1456,6 +1465,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				923F824C206C4D8000034974 /* SafariServices.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1463,6 +1473,9 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				923F8252206C4DD500034974 /* UIKit.framework in Frameworks */,
+				923F8251206C4DC600034974 /* UserNotifications.framework in Frameworks */,
+				923F824F206C4DA500034974 /* XCTest.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1660,6 +1673,9 @@
 		6003F58C195388D20070C39A /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				923F8250206C4DC500034974 /* UserNotifications.framework */,
+				923F824B206C4D8000034974 /* SafariServices.framework */,
+				923F824D206C4D8B00034974 /* SafariServices.framework */,
 				D09005301EDB32D600154410 /* OCMock-iOS/OCMock.framework */,
 				DE45C6641E7DA8CB009E6ACD /* XCTest.framework */,
 				DEB61E781E7C542600C04B96 /* libsqlite3.tbd */,
diff --git a/Example/Messaging/Tests/FIRMessagingClientTest.m b/Example/Messaging/Tests/FIRMessagingClientTest.m
index 5505b70..9c60d9c 100644
--- a/Example/Messaging/Tests/FIRMessagingClientTest.m
+++ b/Example/Messaging/Tests/FIRMessagingClientTest.m
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 
diff --git a/Example/Messaging/Tests/FIRMessagingCodedInputStreamTest.m b/Example/Messaging/Tests/FIRMessagingCodedInputStreamTest.m
index 7cc2d97..bafa714 100644
--- a/Example/Messaging/Tests/FIRMessagingCodedInputStreamTest.m
+++ b/Example/Messaging/Tests/FIRMessagingCodedInputStreamTest.m
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import "FIRMessagingCodedInputStream.h"
 
diff --git a/Example/Messaging/Tests/FIRMessagingConnectionTest.m b/Example/Messaging/Tests/FIRMessagingConnectionTest.m
index 47b29d2..b770cf5 100644
--- a/Example/Messaging/Tests/FIRMessagingConnectionTest.m
+++ b/Example/Messaging/Tests/FIRMessagingConnectionTest.m
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 
diff --git a/Example/Messaging/Tests/FIRMessagingDataMessageManagerTest.m b/Example/Messaging/Tests/FIRMessagingDataMessageManagerTest.m
index 5771337..8aaad51 100644
--- a/Example/Messaging/Tests/FIRMessagingDataMessageManagerTest.m
+++ b/Example/Messaging/Tests/FIRMessagingDataMessageManagerTest.m
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 
diff --git a/Example/Messaging/Tests/FIRMessagingLinkHandlingTest.m b/Example/Messaging/Tests/FIRMessagingLinkHandlingTest.m
index 8f93240..4ef2525 100644
--- a/Example/Messaging/Tests/FIRMessagingLinkHandlingTest.m
+++ b/Example/Messaging/Tests/FIRMessagingLinkHandlingTest.m
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 
diff --git a/Example/Messaging/Tests/FIRMessagingPubSubTest.m b/Example/Messaging/Tests/FIRMessagingPubSubTest.m
index 2981b54..3af1402 100644
--- a/Example/Messaging/Tests/FIRMessagingPubSubTest.m
+++ b/Example/Messaging/Tests/FIRMessagingPubSubTest.m
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import "FIRMessagingPubSub.h"
 
diff --git a/Example/Messaging/Tests/FIRMessagingRegistrarTest.m b/Example/Messaging/Tests/FIRMessagingRegistrarTest.m
index b32851c..863ba4b 100644
--- a/Example/Messaging/Tests/FIRMessagingRegistrarTest.m
+++ b/Example/Messaging/Tests/FIRMessagingRegistrarTest.m
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-@import UIKit;
-@import XCTest;
+#import <UIKit/UIKit.h>
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 
diff --git a/Example/Messaging/Tests/FIRMessagingRemoteNotificationsProxyTest.m b/Example/Messaging/Tests/FIRMessagingRemoteNotificationsProxyTest.m
index 1e1cbf3..3453f11 100644
--- a/Example/Messaging/Tests/FIRMessagingRemoteNotificationsProxyTest.m
+++ b/Example/Messaging/Tests/FIRMessagingRemoteNotificationsProxyTest.m
@@ -15,9 +15,9 @@
  */
 
 #if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
-@import UserNotifications;
+#import <UserNotifications/UserNotifications.h>
 #endif
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 
diff --git a/Example/Messaging/Tests/FIRMessagingSecureSocketTest.m b/Example/Messaging/Tests/FIRMessagingSecureSocketTest.m
index 9f6186b..b86592c 100644
--- a/Example/Messaging/Tests/FIRMessagingSecureSocketTest.m
+++ b/Example/Messaging/Tests/FIRMessagingSecureSocketTest.m
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 
diff --git a/Example/Messaging/Tests/FIRMessagingServiceTest.m b/Example/Messaging/Tests/FIRMessagingServiceTest.m
index c8d61c2..0a41314 100644
--- a/Example/Messaging/Tests/FIRMessagingServiceTest.m
+++ b/Example/Messaging/Tests/FIRMessagingServiceTest.m
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-@import UIKit;
-@import XCTest;
+#import <UIKit/UIKit.h>
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 
diff --git a/Example/Messaging/Tests/FIRMessagingTest.m b/Example/Messaging/Tests/FIRMessagingTest.m
index 3521290..c2a136a 100644
--- a/Example/Messaging/Tests/FIRMessagingTest.m
+++ b/Example/Messaging/Tests/FIRMessagingTest.m
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import <OCMock/OCMock.h>
 #import <FirebaseInstanceID/FirebaseInstanceID.h>
diff --git a/Firebase/Core/FIRNetworkConstants.m b/Firebase/Core/FIRNetworkConstants.m
index a92e0e2..c958201 100644
--- a/Firebase/Core/FIRNetworkConstants.m
+++ b/Firebase/Core/FIRNetworkConstants.m
@@ -14,7 +14,7 @@
 
 #import "Private/FIRNetworkConstants.h"
 
-@import Foundation;
+#import <Foundation/Foundation.h>
 
 NSString *const kFIRNetworkBackgroundSessionConfigIDPrefix =
     @"com.firebase.network.background-upload";
diff --git a/Firebase/Core/Private/FIRMutableDictionary.h b/Firebase/Core/Private/FIRMutableDictionary.h
index ebe2d33..6829dbc 100644
--- a/Firebase/Core/Private/FIRMutableDictionary.h
+++ b/Firebase/Core/Private/FIRMutableDictionary.h
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import Foundation;
+#import <Foundation/Foundation.h>
 
 /// A mutable dictionary that provides atomic accessor and mutators.
 @interface FIRMutableDictionary : NSObject
diff --git a/Firebase/Core/Private/FIRNetwork.h b/Firebase/Core/Private/FIRNetwork.h
index aac0bca..32be35a 100644
--- a/Firebase/Core/Private/FIRNetwork.h
+++ b/Firebase/Core/Private/FIRNetwork.h
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import Foundation;
+#import <Foundation/Foundation.h>
 
 #import "FIRNetworkConstants.h"
 #import "FIRNetworkLoggerProtocol.h"
diff --git a/Firebase/Core/Private/FIRNetworkConstants.h b/Firebase/Core/Private/FIRNetworkConstants.h
index 5878088..d318581 100644
--- a/Firebase/Core/Private/FIRNetworkConstants.h
+++ b/Firebase/Core/Private/FIRNetworkConstants.h
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import Foundation;
+#import <Foundation/Foundation.h>
 
 /// Error codes in Firebase Network error domain.
 /// Note: these error codes should never change. It would make it harder to decode the errors if
diff --git a/Firebase/Core/Private/FIRNetworkLoggerProtocol.h b/Firebase/Core/Private/FIRNetworkLoggerProtocol.h
index 4a4315b..add70fc 100644
--- a/Firebase/Core/Private/FIRNetworkLoggerProtocol.h
+++ b/Firebase/Core/Private/FIRNetworkLoggerProtocol.h
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import Foundation;
+#import <Foundation/Foundation.h>
 
 #import "FIRLoggerLevel.h"
 #import "FIRNetworkMessageCode.h"
diff --git a/Firebase/Core/Private/FIRNetworkURLSession.h b/Firebase/Core/Private/FIRNetworkURLSession.h
index 3b60317..a51b8a9 100644
--- a/Firebase/Core/Private/FIRNetworkURLSession.h
+++ b/Firebase/Core/Private/FIRNetworkURLSession.h
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@import Foundation;
+#import <Foundation/Foundation.h>
 
 #import "FIRNetworkLoggerProtocol.h"
 
diff --git a/Firebase/Core/Private/FIRReachabilityChecker.h b/Firebase/Core/Private/FIRReachabilityChecker.h
index afbc89b..3a6a531 100644
--- a/Firebase/Core/Private/FIRReachabilityChecker.h
+++ b/Firebase/Core/Private/FIRReachabilityChecker.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-@import Foundation;
-@import SystemConfiguration;
+#import <Foundation/Foundation.h>
+#import <SystemConfiguration/SystemConfiguration.h>
 
 /// Reachability Status
 typedef enum {
diff --git a/Functions/Example/IntegrationTests/FIRIntegrationTests.m b/Functions/Example/IntegrationTests/FIRIntegrationTests.m
index 15a5af5..bd4b127 100644
--- a/Functions/Example/IntegrationTests/FIRIntegrationTests.m
+++ b/Functions/Example/IntegrationTests/FIRIntegrationTests.m
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import "FIRError.h"
 #import "FIRFunctions+Internal.h"
diff --git a/Functions/Example/TestUtils/FUNFakeApp.m b/Functions/Example/TestUtils/FUNFakeApp.m
index 5b31d01..370273b 100644
--- a/Functions/Example/TestUtils/FUNFakeApp.m
+++ b/Functions/Example/TestUtils/FUNFakeApp.m
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#import <Foundation/Foundation.h>
+
 #import "FUNFakeApp.h"
 
 NS_ASSUME_NONNULL_BEGIN
diff --git a/Functions/Example/Tests/FIRFunctionsTests.m b/Functions/Example/Tests/FIRFunctionsTests.m
index bec96e6..5d11601 100644
--- a/Functions/Example/Tests/FIRFunctionsTests.m
+++ b/Functions/Example/Tests/FIRFunctionsTests.m
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import "FIRFunctions+Internal.h"
 #import "FIRFunctions.h"
diff --git a/Functions/Example/Tests/FUNSerializerTests.m b/Functions/Example/Tests/FUNSerializerTests.m
index 707c3e7..ca2198e 100644
--- a/Functions/Example/Tests/FUNSerializerTests.m
+++ b/Functions/Example/Tests/FUNSerializerTests.m
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-@import XCTest;
+#import <XCTest/XCTest.h>
 
 #import "FIRError.h"
 #import "FUNSerializer.h"
diff --git a/scripts/check_no_module_imports.sh b/scripts/check_no_module_imports.sh
new file mode 100755
index 0000000..c00c1db
--- /dev/null
+++ b/scripts/check_no_module_imports.sh
@@ -0,0 +1,41 @@
+# Copyright 2018 Google
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Fail if any source files contain Objective-C module @imports, excluding:
+#   * Example sources
+#   * Sample sources
+
+options=(
+  -n  # show line numbers
+  -I  # exclude binary files
+  '^@import'
+)
+
+function exit_with_error {
+  echo "ERROR: @import statement found in the files above. Please use #import instead."
+  exit 1
+}
+
+git grep "${options[@]}" \
+  -- ':(exclude,glob)**/Example/**' ':(exclude,glob)**/Sample/**' && exit_with_error
+
+# Tests are under the Example directory, so we have to separately grep them for
+# @import statements (otherwise they'd be excluded).
+git grep "${options[@]}" \
+  -- ':(glob)**/Tests/**' ':(glob)**/TestUtils/**' ':(glob)**/IntegrationTests/**' && \
+  exit_with_error
+
+# We need to explicitly exit 0, since we expect `git grep` to return an error
+# if no @import calls are found.
+exit 0