fix: Write SampleRate as float to manifest

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixes
 
+- Fixed an issue where the SDK would write the `SampleRate` as an `int` instead of a `float` to the Android Manifest, causing issues during the Android SDK's initialization ([#1872](https://github.com/getsentry/sentry-unity/pull/1872))
 - The SDK no longer calls into `Application.persistentDataPath` on unknown platforms. This prevents crashes during startup on platforms with restricted disk access like the Nintendo Switch ([#1870](https://github.com/getsentry/sentry-unity/pull/1870))
 
 ### Dependencies

src/Sentry.Unity.Editor/Android/AndroidManifestConfiguration.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.IO;
 using System.Text;
 using System.Xml;
@@ -157,7 +158,8 @@ internal void ModifyManifest(string basePath)
 
         if (_options.SampleRate.HasValue)
         {
-            _logger.LogDebug("Setting SampleRate: {0}", _options.SampleRate);
+            // To keep the logs in line with what the SDK writes to the AndroidManifest we're formatting here too
+            _logger.LogDebug("Setting SampleRate: {0}", ((float)_options.SampleRate).ToString("F", CultureInfo.InvariantCulture));
             androidManifest.SetSampleRate(_options.SampleRate.Value);
         }
 
@@ -420,7 +422,8 @@ public void AddDisclaimerComment() =>
     internal void SetDsn(string dsn) => SetMetaData($"{SentryPrefix}.dsn", dsn);
 
     internal void SetSampleRate(float sampleRate) =>
-        SetMetaData($"{SentryPrefix}.sample-rate", sampleRate.ToString());
+        // Keeping the sample-rate as float: https://learn.microsoft.com/en-us/dotnet/standard/base-types/standard-numeric-format-strings
+        SetMetaData($"{SentryPrefix}.sample-rate", sampleRate.ToString("F", CultureInfo.InvariantCulture));
 
     internal void SetRelease(string release) => SetMetaData($"{SentryPrefix}.release", release);
 

test/Sentry.Unity.Editor.Tests/Android/AndroidManifestConfigurationTests.cs

@@ -223,17 +223,18 @@ public void ModifyManifest_DiagnosticLevel_TestCases(
     }
 
     [Test]
-    public void ModifyManifest_SampleRate_SetIfNotNull()
+    [TestCase(0.45f, "0.45")]
+    [TestCase(1, "1.00")]
+    public void ModifyManifest_SampleRate_SetIfNotNull(float sampleRate, string expectedSampleRate)
     {
-        const float expected = 0.6f;
-        _fixture.SentryUnityOptions!.SampleRate = expected;
+        _fixture.SentryUnityOptions!.SampleRate = sampleRate;
         var sut = _fixture.GetSut();
         var manifest = WithAndroidManifest(basePath => sut.ModifyManifest(basePath));
 
-        _fixture.UnityTestLogger.AssertLogContains(SentryLevel.Debug, $"Setting SampleRate: {expected}");
+        _fixture.UnityTestLogger.AssertLogContains(SentryLevel.Debug, $"Setting SampleRate: {expectedSampleRate}");
 
         Assert.True(manifest.Contains(
-                $"<meta-data android:name=\"io.sentry.sample-rate\" android:value=\"{expected}\" />"),
+                $"<meta-data android:name=\"io.sentry.sample-rate\" android:value=\"{expectedSampleRate}\" />"),
             $"Expected 'io.sentry.sample-rate' in Manifest:\n{manifest}");
     }