fix(storage): guard prepare timestamp serialization

src/EventStore.Core.Tests/Services/Storage/Chaser/when_chaser_reads_commit_event.cs

@@ -31,7 +31,7 @@ public override async ValueTask When(CancellationToken token)
 			transactionOffset: 0xBEEF,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.Data,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },

src/EventStore.Core.Tests/Services/Storage/Chaser/when_chaser_reads_committed_prepare_event.cs

@@ -30,7 +30,7 @@ public override async ValueTask When(CancellationToken token)
 			transactionOffset: 0xBEEF,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.IsCommitted | PrepareFlags.TransactionEnd,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },

src/EventStore.Core.Tests/Services/Storage/Chaser/when_chaser_reads_prepare_event.cs

@@ -30,7 +30,7 @@ public override async ValueTask When(CancellationToken token)
 			transactionOffset: 0xBEEF,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.SingleWrite,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },

src/EventStore.Core.Tests/TransactionLog/Scavenging/Helpers/TFChunkDbCreationHelper.cs

@@ -581,6 +581,11 @@ public Rec(RecType type, int transaction, string streamId, string eventType, Dat
 		Transaction = transaction;
 		StreamId = streamId;
 		EventType = eventType ?? string.Empty;
+		if (timestamp.HasValue && timestamp.Value.Kind != DateTimeKind.Utc)
+		{
+			throw new ArgumentException("Scavenge fixture prepare timestamps must be UTC.", nameof(timestamp));
+		}
+
 		TimeStamp = timestamp ?? DateTime.UtcNow;
 		Version = version;
 		EventNumber = eventNumber;

src/EventStore.Core.Tests/TransactionLog/tfchunk_get_actual_raw_position_should.cs

@@ -27,7 +27,7 @@ private IPrepareLogRecord<TStreamId> CreateRecord(long logPosition, int dataSize
 	{
 		return LogRecord.Prepare(_recordFactory, logPosition, Guid.NewGuid(), Guid.NewGuid(), 0, 0, _streamId, 1,
 			PrepareFlags.None, _eventTypeId, new byte[dataSize], Array.Empty<byte>(),
-			new DateTime(2000, 1, 1, 12, 0, 0));
+			new DateTime(2000, 1, 1, 12, 0, 0, DateTimeKind.Utc));
 	}
 
 	private async ValueTask<TFChunk> CreateChunk(int numEvents, bool completed, bool scavenged,

src/EventStore.Core.Tests/TransactionLog/when_appending_past_end_of_a_tfchunk.cs

@@ -25,7 +25,8 @@ public override async Task SetUp()
 		var eventTypeId = LogFormatHelper<TLogFormat, TStreamId>.EventTypeId;
 
 		var record = LogRecord.Prepare(recordFactory, 15556, _corrId, _eventId, 15556, 0, streamId, 1,
-			PrepareFlags.None, eventTypeId, new byte[12], new byte[15], new DateTime(2000, 1, 1, 12, 0, 0));
+			PrepareFlags.None, eventTypeId, new byte[12], new byte[15],
+			new DateTime(2000, 1, 1, 12, 0, 0, DateTimeKind.Utc));
 		_chunk = await TFChunkHelper.CreateNewChunk(Filename, 20);
 		_written = (await _chunk.TryAppend(record, CancellationToken.None)).Success;
 	}

src/EventStore.Core.Tests/TransactionLog/when_appending_to_a_tfchunk_and_flushing.cs

@@ -26,7 +26,8 @@ public override async Task TestFixtureSetUp()
 		var streamId = LogFormatHelper<TLogFormat, TStreamId>.StreamId;
 		var eventTypeId = LogFormatHelper<TLogFormat, TStreamId>.EventTypeId;
 		_record = LogRecord.Prepare(recordFactory, 0, _corrId, _eventId, 0, 0, streamId, 1,
-			PrepareFlags.None, eventTypeId, new byte[12], new byte[15], new DateTime(2000, 1, 1, 12, 0, 0));
+			PrepareFlags.None, eventTypeId, new byte[12], new byte[15],
+			new DateTime(2000, 1, 1, 12, 0, 0, DateTimeKind.Utc));
 		_chunk = await TFChunkHelper.CreateNewChunk(Filename);
 		_result = await _chunk.TryAppend(_record, CancellationToken.None);
 		await _chunk.Flush(CancellationToken.None);

src/EventStore.Core.Tests/TransactionLog/when_appending_to_a_tfchunk_without_flush.cs

@@ -27,7 +27,8 @@ public override async Task TestFixtureSetUp()
 		var eventTypeId = LogFormatHelper<TLogFormat, TStreamId>.EventTypeId;
 
 		_record = LogRecord.Prepare(recordFactory, 0, _corrId, _eventId, 0, 0, streamId, 1,
-			PrepareFlags.None, eventTypeId, new byte[12], new byte[15], new DateTime(2000, 1, 1, 12, 0, 0));
+			PrepareFlags.None, eventTypeId, new byte[12], new byte[15],
+			new DateTime(2000, 1, 1, 12, 0, 0, DateTimeKind.Utc));
 		_chunk = await TFChunkHelper.CreateNewChunk(Filename);
 		_result = await _chunk.TryAppend(_record, CancellationToken.None);
 	}

src/EventStore.Core.Tests/TransactionLog/when_chasing_a_chunked_transaction_log.cs

@@ -98,7 +98,7 @@ public async Task open_starts_from_the_latest_chaser_checkpoint()
 			transactionOffset: 0,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },
@@ -138,7 +138,7 @@ public async Task try_read_returns_record_when_writerchecksum_ahead()
 			transactionOffset: 0,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },
@@ -195,7 +195,7 @@ public async Task try_read_returns_record_when_record_bigger_than_internal_buffe
 			transactionOffset: 0,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[9000],
@@ -239,7 +239,7 @@ public async Task try_read_returns_record_when_writerchecksum_equal()
 			transactionOffset: 0,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },
@@ -274,7 +274,7 @@ public void try_read_returns_false_when_writer_checksum_is_ahead_but_not_enough_
 	                                                transactionPosition: 0,
 	                                                eventStreamId: "WorldEnding",
 	                                                expectedVersion: 1234,
-	                                                timeStamp: new DateTime(2012, 12, 21),
+	                                                timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 	                                                flags: PrepareFlags.None,
 	                                                eventType: "type",
 	                                                data: new byte[] { 1, 2, 3, 4, 5 },
@@ -309,7 +309,7 @@ public void try_read_returns_false_when_writer_checksum_is_ahead_but_not_enough_
 	                                                transactionPosition: 0,
 	                                                eventStreamId: "WorldEnding",
 	                                                expectedVersion: 1234,
-	                                                timeStamp: new DateTime(2012, 12, 21),
+	                                                timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 	                                                flags: PrepareFlags.None,
 	                                                eventType: "type",
 	                                                data: new byte[] { 1, 2, 3, 4, 5 },
@@ -352,7 +352,7 @@ public void try_read_returns_properly_when_writer_is_written_to_while_chasing()
 	                                                transactionPosition: 0,
 	                                                eventStreamId: "WorldEnding",
 	                                                expectedVersion: 1234,
-	                                                timeStamp: new DateTime(2012, 12, 21),
+	                                                timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 	                                                flags: PrepareFlags.None,
 	                                                eventType: "type",
 	                                                data: new byte[] { 1, 2, 3, 4, 5 },
@@ -377,7 +377,7 @@ public void try_read_returns_properly_when_writer_is_written_to_while_chasing()
 	                                                 transactionPosition: 0,
 	                                                 eventStreamId: "WorldEnding",
 	                                                 expectedVersion: 4321,
-	                                                 timeStamp: new DateTime(2012, 12, 21),
+	                                                 timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 	                                                 flags: PrepareFlags.None,
 	                                                 eventType: "type",
 	                                                 data: new byte[] { 3, 2, 1 },

src/EventStore.Core.Tests/TransactionLog/when_closing_the_database.cs

@@ -41,7 +41,7 @@ private static IPrepareLogRecord<TStreamId> CreateRecord()
 			transactionOffset: 0,
 			eventStreamId: streamId,
 			expectedVersion: -1,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.SingleWrite,
 			eventType: eventTypeId,
 			data: new byte[123],

src/EventStore.Core.Tests/TransactionLog/when_reading_from_a_cached_tfchunk.cs

@@ -31,7 +31,8 @@ public override async Task TestFixtureSetUp()
 		var eventTypeId = LogFormatHelper<TLogFormat, TStreamId>.EventTypeId;
 
 		_record = LogRecord.Prepare(recordFactory, 0, _corrId, _eventId, 0, 0, streamId, 1,
-			PrepareFlags.None, eventTypeId, new byte[12], new byte[15], new DateTime(2000, 1, 1, 12, 0, 0));
+			PrepareFlags.None, eventTypeId, new byte[12], new byte[15],
+			new DateTime(2000, 1, 1, 12, 0, 0, DateTimeKind.Utc));
 		_chunk = await TFChunkHelper.CreateNewChunk(Filename);
 		_result = await _chunk.TryAppend(_record, CancellationToken.None);
 		await _chunk.Flush(CancellationToken.None);

src/EventStore.Core.Tests/TransactionLog/when_uncaching_a_tfchunk.cs

@@ -31,7 +31,8 @@ public override async Task TestFixtureSetUp()
 		var eventTypeId = LogFormatHelper<TLogFormat, TStreamId>.EventTypeId;
 
 		_record = LogRecord.Prepare(recordFactory, 0, _corrId, _eventId, 0, 0, streamId, 1,
-			PrepareFlags.None, eventTypeId, new byte[12], new byte[15], new DateTime(2000, 1, 1, 12, 0, 0));
+			PrepareFlags.None, eventTypeId, new byte[12], new byte[15],
+			new DateTime(2000, 1, 1, 12, 0, 0, DateTimeKind.Utc));
 		_chunk = await TFChunkHelper.CreateNewChunk(Filename);
 		_result = await _chunk.TryAppend(_record, CancellationToken.None);
 		await _chunk.Flush(CancellationToken.None);

src/EventStore.Core.Tests/TransactionLog/when_writing_a_new_chunked_transaction_file.cs

@@ -41,7 +41,7 @@ public async Task a_record_can_be_written()
 			transactionOffset: 0,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },

src/EventStore.Core.Tests/TransactionLog/when_writing_an_existing_chunked_transaction_file_with_checksum.cs

@@ -52,7 +52,7 @@ public async Task a_record_can_be_written()
 			transactionPos: 0,
 			transactionOffset: 0,
 			eventStreamId: streamId,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },

src/EventStore.Core.Tests/TransactionLog/when_writing_an_existing_chunked_transaction_file_with_checksum_and_data_bigger_than_buffer.cs

@@ -58,7 +58,7 @@ public async Task a_record_can_be_written()
 			transactionOffset: 543,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.SingleWrite,
 			eventType: eventTypeId,
 			data: bytes,

src/EventStore.Core.Tests/TransactionLog/when_writing_an_existing_chunked_transaction_file_with_not_enough_space_in_chunk.cs

@@ -55,7 +55,7 @@ public async Task a_record_is_not_written_at_first_but_written_on_second_try()
 			transactionPos: 0,
 			transactionOffset: 0,
 			eventStreamId: streamId,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },
@@ -72,7 +72,7 @@ public async Task a_record_is_not_written_at_first_but_written_on_second_try()
 			transactionPos: pos,
 			transactionOffset: 0,
 			eventStreamId: streamId,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },
@@ -89,7 +89,7 @@ public async Task a_record_is_not_written_at_first_but_written_on_second_try()
 			transactionPos: pos,
 			transactionOffset: 0,
 			eventStreamId: streamId,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.None,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },

src/EventStore.Core.Tests/TransactionLog/when_writing_multiple_records_to_a_tfchunk.cs

@@ -34,13 +34,15 @@ public override async Task TestFixtureSetUp()
 		var eventTypeId2 = LogFormatHelper<TLogFormat, TStreamId>.EventTypeId2;
 
 		_prepare1 = LogRecord.Prepare(recordFactory, 0, _corrId, _eventId, 0, 0, streamId1, 1,
-			PrepareFlags.None, eventTypeId1, new byte[12], new byte[15], new DateTime(2000, 1, 1, 12, 0, 0));
+			PrepareFlags.None, eventTypeId1, new byte[12], new byte[15],
+			new DateTime(2000, 1, 1, 12, 0, 0, DateTimeKind.Utc));
 		var r1 = await _chunk.TryAppend(_prepare1, CancellationToken.None);
 		_written1 = r1.Success;
 		_position1 = r1.OldPosition;
 
 		_prepare2 = LogRecord.Prepare(recordFactory, r1.NewPosition, _corrId, _eventId, 0, 0, streamId2, 2,
-			PrepareFlags.None, eventTypeId2, new byte[12], new byte[15], new DateTime(2000, 1, 1, 12, 0, 0));
+			PrepareFlags.None, eventTypeId2, new byte[12], new byte[15],
+			new DateTime(2000, 1, 1, 12, 0, 0, DateTimeKind.Utc));
 		var r2 = await _chunk.TryAppend(_prepare2, CancellationToken.None);
 		_written2 = r2.Success;
 		_position2 = r2.OldPosition;

src/EventStore.Core.Tests/TransactionLog/when_writing_prepare_record_to_file.cs

@@ -45,7 +45,7 @@ public async Task SetUp()
 			transactionOffset: 0xBEEF,
 			eventStreamId: streamId,
 			expectedVersion: 1234,
-			timeStamp: new DateTime(2012, 12, 21),
+			timeStamp: new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc),
 			flags: PrepareFlags.SingleWrite,
 			eventType: eventTypeId,
 			data: new byte[] { 1, 2, 3, 4, 5 },
@@ -86,7 +86,7 @@ public async Task the_data_is_written()
 		Assert.AreEqual(p.EventId, _eventId);
 		Assert.AreEqual(p.EventStreamId, streamId);
 		Assert.AreEqual(p.ExpectedVersion, 1234);
-		Assert.That(p.TimeStamp, Is.EqualTo(new DateTime(2012, 12, 21)).Within(7).Milliseconds);
+		Assert.That(p.TimeStamp, Is.EqualTo(new DateTime(2012, 12, 21, 0, 0, 0, DateTimeKind.Utc)).Within(7).Milliseconds);
 		Assert.AreEqual(p.Flags, PrepareFlags.SingleWrite);
 		Assert.AreEqual(p.EventType, eventTypeId);
 		Assert.AreEqual(p.Data.Length, 5);

src/EventStore.Core.XUnit.Tests/Scavenge/Infrastructure/StreamMetadatas.cs

@@ -27,15 +27,16 @@ public class StreamMetadatas
 		new StreamMetadata(truncateBefore: EventNumber.DeletedStream);
 
 	public static DateTime EffectiveNow { get; } = new DateTime(2022, 1, 5, 00, 00, 00);
-	public static DateTime Expired { get; } = EffectiveNow - TimeSpan.FromDays(3);
-	public static DateTime Cutoff { get; } = EffectiveNow - MaxAgeTimeSpan;
-	public static DateTime Active { get; } = EffectiveNow - TimeSpan.FromDays(1);
+	private static DateTime EffectiveNowRecordTimestamp { get; } = new DateTime(2022, 1, 5, 00, 00, 00, DateTimeKind.Utc);
+	public static DateTime Expired { get; } = EffectiveNowRecordTimestamp - TimeSpan.FromDays(3);
+	public static DateTime Cutoff { get; } = EffectiveNowRecordTimestamp - MaxAgeTimeSpan;
+	public static DateTime Active { get; } = EffectiveNowRecordTimestamp - TimeSpan.FromDays(1);
 
 	public static Rec ScavengePointRec(int transaction, int threshold = 0, DateTime? timeStamp = null) => Rec.Write(
 		transaction: transaction,
 		stream: SystemStreams.ScavengePointsStream,
 		eventType: SystemEventTypes.ScavengePoint,
-		timestamp: timeStamp ?? EffectiveNow,
+		timestamp: timeStamp ?? EffectiveNowRecordTimestamp,
 		data: new ScavengePointPayload
 		{
 			Threshold = threshold,

src/EventStore.Core.XUnit.Tests/TransactionLog/LogRecords/PrepareLogRecordViewTests.cs

@@ -71,6 +71,27 @@ public void should_have_correct_properties()
 		Assert.Equal(Version, _prepare.Version);
 	}
 
+	[Fact]
+	public void constructor_should_reject_non_utc_timestamp()
+	{
+		Assert.Throws<ArgumentException>(() => new PrepareLogRecord(
+			LogPosition,
+			_correlationId,
+			_eventId,
+			TransactionPosition,
+			TransactionOffset,
+			EventStreamId,
+			null,
+			ExpectedVersion,
+			DateTime.Now,
+			Flags,
+			EventType,
+			null,
+			_data,
+			_metadata,
+			Version));
+	}
+
 	[Fact]
 	public void parsed_record_should_preserve_utc_timestamp_kind()
 	{

src/EventStore.Core/Services/Storage/InMemory/SingleEventInMemoryStream.cs

@@ -149,7 +149,7 @@ public void Write(string eventType, ReadOnlyMemory<byte> data)
 			eventStreamId: _streamName,
 			eventStreamIdSize: null,
 			expectedVersion: _eventNumber - 1,
-			timeStamp: DateTime.Now,
+			timeStamp: DateTime.UtcNow,
 			flags: Flags,
 			eventType: eventType,
 			eventTypeSize: null,

src/EventStore.Core/TransactionLog/LogRecords/PrepareLogRecord.cs

@@ -156,6 +156,11 @@ public PrepareLogRecord(long logPosition,
 			throw new ArgumentOutOfRangeException("expectedVersion");
 		}
 
+		if (timeStamp.Kind != DateTimeKind.Utc)
+		{
+			throw new ArgumentException("Prepare log record timestamps must be UTC.", nameof(timeStamp));
+		}
+
 		Flags = flags;
 		TransactionPosition = transactionPosition;
 		TransactionOffset = transactionOffset;