fix: Adds AddGoogleDiagnostics empty overload.

To avoid ambiguity, which results in a compiler error, when not specifying any of the optional parameters for the other overloads.
This is the same as what was done on #7642 for the ASP.NET Core packages, but for the Common package instead, which had the same issue.

apis/Google.Cloud.Diagnostics.AspNetCore/Google.Cloud.Diagnostics.AspNetCore.IntegrationTests/DiagnosticsTests.cs

@@ -65,7 +65,7 @@ public async Task UseGoogleDiagnostics_ConfiguresServices_Default()
             using var client = server.CreateClient();
             await TestTrace(testId, startTime, client);
             await TestLogging(testId, startTime, client);
-            await TestErrorReporting(testId, client);
+            await TestErrorReporting(testId, client, verifyServiceAndVersion: false);
         }
 
         [Fact]
@@ -182,7 +182,7 @@ private static async Task TestTrace(string testId, DateTimeOffset startTime, Htt
             Assert.False(response.Headers.Contains(TraceHeaderContext.TraceHeader));
         }
 
-        private static async Task TestErrorReporting(string testId, HttpClient client)
+        private static async Task TestErrorReporting(string testId, HttpClient client, bool verifyServiceAndVersion = true)
         {
             await Assert.ThrowsAsync<Exception>(() => client.GetAsync($"/ErrorReporting/{nameof(ErrorReportingController.ThrowsException)}/{testId}"));
             var errorEvent = ErrorEventEntryVerifiers.VerifySingle(ErrorEventEntryPolling.Default, testId);

apis/Google.Cloud.Diagnostics.Common/Google.Cloud.Diagnostics.Common.IntegrationTests/DiagnosticsTests.cs

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+using Google.Api.Gax;
 using Google.Cloud.ClientTesting;
 using Google.Cloud.Logging.Type;
 using Microsoft.Extensions.DependencyInjection;
@@ -40,15 +41,20 @@ public DiagnosticsTests()
             _startTime = DateTimeOffset.UtcNow;
         }
 
+        private static class EmptyHostBuilder
+        {
+            public static IHostBuilder CreateHostBuilder() =>
+                new HostBuilder()
+                    .ConfigureLogging(builder => builder.ClearProviders())
+                    .ConfigureServices(services => services.AddGoogleDiagnostics());
+        }
+
         private static class DefaultHostBuilder
         {
             public static IHostBuilder CreateHostBuilder() =>
                 new HostBuilder()
                     .ConfigureLogging(builder => builder.ClearProviders())
-                    .ConfigureServices(services =>
-                    {
-                        services.AddGoogleDiagnostics(ProjectId, Service, Version);
-                    });
+                    .ConfigureServices(services => services.AddGoogleDiagnostics(ProjectId, Service, Version));
         }
 
         private static class WithOptionsHostBuilder
@@ -57,14 +63,12 @@ private static class WithOptionsHostBuilder
                 new HostBuilder()
                     .ConfigureLogging(builder => builder.ClearProviders())
                     .ConfigureServices(services =>
-                    {
                         // We don't care much about which options we are setting.
                         // These are for testing that all the extension method overloads work as expected.
                         services.AddGoogleDiagnostics(ProjectId, Service, Version,
                             TraceOptions.Create(retryOptions: RetryOptions.NoRetry(ExceptionHandling.Propagate)),
                             LoggingOptions.Create(retryOptions: RetryOptions.NoRetry(ExceptionHandling.Propagate)),
-                            ErrorReportingOptions.CreateInstance(retryOptions: RetryOptions.NoRetry(ExceptionHandling.Propagate)));
-                    });
+                            ErrorReportingOptions.CreateInstance(retryOptions: RetryOptions.NoRetry(ExceptionHandling.Propagate))));
         }
 
         private static class WithServiceOptionsHostBuilder
@@ -106,6 +110,11 @@ public static IEnumerable<object[]> HostBuilderData
                 yield return new object[] { (Func<IHostBuilder>)DefaultHostBuilder.CreateHostBuilder };
                 yield return new object[] { (Func<IHostBuilder>)WithOptionsHostBuilder.CreateHostBuilder };
                 yield return new object[] { (Func<IHostBuilder>)WithServiceOptionsHostBuilder.CreateHostBuilder };
+                // Skip these tests if we are not running on GCP
+                if (Platform.Instance().Type != PlatformType.Unknown)
+                {
+                    yield return new object[] { (Func<IHostBuilder>)EmptyHostBuilder.CreateHostBuilder };
+                }
             }
         }
 
@@ -193,7 +202,7 @@ public async Task LogsExceptionAsync(Func<IHostBuilder> createHostBuilder)
 
                 var errorEvent = ErrorEventEntryVerifiers.VerifySingle(ErrorEventEntryPolling.Default, _testId);
                 ErrorEventEntryVerifiers.VerifyFullErrorEventLogged(
-                    errorEvent, _testId, nameof(ThrowsException), verifyHttpContext: false);
+                    errorEvent, _testId, nameof(ThrowsException), verifyHttpContext: false, verifyServiceAndVersion: false);
             }
             finally
             {

apis/Google.Cloud.Diagnostics.Common/Google.Cloud.Diagnostics.Common.IntegrationTests/ErrorReporting/ErrorEventEntryVerifiers.cs

@@ -50,9 +50,10 @@ public static IEnumerable<ErrorEvent> VerifyMany(ErrorEventEntryPolling polling,
         /// Checks that an <see cref="ErrorEvent"/> contains valid data,
         /// including HTTP Context data.
         /// </summary>
-        public static void VerifyFullErrorEventLogged(ErrorEvent errorEvent, string testId, string functionName, bool verifyHttpContext = true)
+        public static void VerifyFullErrorEventLogged(ErrorEvent errorEvent, string testId, string functionName,
+            bool verifyHttpContext = true, bool verifyServiceAndVersion = true)
         {
-            VerifyErrorEventLogged(errorEvent, testId, functionName);
+            VerifyErrorEventLogged(errorEvent, testId, functionName, verifyServiceAndVersion);
             if (verifyHttpContext)
             {
                 VerifyHttpContextLogged(errorEvent);
@@ -66,10 +67,13 @@ public static void VerifyFullErrorEventLogged(ErrorEvent errorEvent, string test
         /// Google.Cloud.Diagnostics.GoogleExceptionLogger is used instead of the
         /// Google.Cloud.Diagnostics.GoogleWebApiExceptionLogger.
         /// </summary>
-        public static void VerifyErrorEventLogged(ErrorEvent errorEvent, string testId, string functionName)
+        public static void VerifyErrorEventLogged(ErrorEvent errorEvent, string testId, string functionName, bool verifyServiceAndVersion = true)
         {
-            Assert.Equal(EntryData.Service, errorEvent.ServiceContext.Service);
-            Assert.Equal(EntryData.Version, errorEvent.ServiceContext.Version);
+            if (verifyServiceAndVersion)
+            {
+                Assert.Equal(EntryData.Service, errorEvent.ServiceContext.Service);
+                Assert.Equal(EntryData.Version, errorEvent.ServiceContext.Version);
+            }
 
             Assert.Contains(functionName, errorEvent.Message);
             Assert.Contains(testId, errorEvent.Message);

apis/Google.Cloud.Diagnostics.Common/Google.Cloud.Diagnostics.Common/GoogleDiagnosticsExtensions.cs

@@ -21,6 +21,21 @@ namespace Google.Cloud.Diagnostics.Common
     /// </summary>
     public static class GoogleDiagnosticsExtensions
     {
+        /// <summary>
+        /// Configures Google Diagnostics to be used in non ASP.NET Core applications.
+        /// </summary>
+        /// <remarks>
+        /// Note that the Google Cloud Project ID to use is required and it can only be
+        /// obtained from the environment if running on GCP. This means that this overload
+        /// can only be used when running on GCP. If you are not running on GCP or need to specify
+        /// the Google Cloud Project ID, you can use any of
+        /// <see cref="AddGoogleDiagnostics(IServiceCollection, TraceServiceOptions, LoggingServiceOptions, ErrorReportingServiceOptions)"/>
+        /// or 
+        /// <see cref="AddGoogleDiagnostics(IServiceCollection, string, string, string, TraceOptions, LoggingOptions, ErrorReportingOptions)"/>.
+        /// </remarks>
+        public static IServiceCollection AddGoogleDiagnostics(this IServiceCollection services) =>
+            services.AddGoogleDiagnostics((TraceServiceOptions)null);
+
         /// <summary>
         /// Configures Google Diagnostics to be used in non ASP.NET Core applications.
         /// </summary>