Address a couple log generator issues.

src/Generators/Microsoft.Gen.Logging/Emission/Emitter.Method.cs

@@ -91,7 +91,7 @@ private void GenLogMethod(LoggingMethod lm)
         }
         else
         {
-            OutLn($"new(0, {eventName}),");
+            OutLn($"new({GetNonRandomizedHashCode(eventName)}, {eventName}),");
         }
 
         OutLn($"{stateName},");
@@ -134,6 +134,26 @@ private void GenLogMethod(LoggingMethod lm)
         OutLn($"{stateName}.Clear();");
         OutCloseBrace();
 
+        /// <summary>
+        /// Returns a non-randomized hash code for the given string.
+        /// </summary>
+        /// <remarks>
+        /// We always return a positive value.
+        /// This code is cloned from the logging generator in dotnet/runtime in
+        /// order to retain the same event ids when upgrading to this generator.
+        /// </remarks>
+        static int GetNonRandomizedHashCode(string s)
+        {
+            const int Mult = 16_777_619;
+            uint result = 2_166_136_261u;
+            foreach (char c in s)
+            {
+                result = (c ^ result) * Mult;
+            }
+
+            return Math.Abs((int)result);
+        }
+
         static bool ShouldStringifyParameter(LoggingMethodParameter p)
         {
             if (p.IsReference)
@@ -395,7 +415,7 @@ void GenTagWrites(LoggingMethod lm, string stateName, out int numReservedUnclass
 
             foreach (var p in lm.Parameters)
             {
-                if (p.HasProperties && p.SkipNullProperties)
+                if (p.HasProperties && p.SkipNullProperties && !p.HasTagProvider)
                 {
                     p.TraverseParameterPropertiesTransitively((propertyChain, member) =>
                     {

test/Generators/Microsoft.Gen.Logging/Generated/LogMethodTests.cs

@@ -231,47 +231,47 @@ public void ConstructorVariationsTests()
         Assert.Null(collector.LatestRecord.Exception);
         Assert.Equal("M1 One", collector.LatestRecord.Message);
         Assert.Equal(LogLevel.Error, collector.LatestRecord.Level);
-        Assert.Equal(0, collector.LatestRecord.Id.Id);
+        Assert.NotEqual(0, collector.LatestRecord.Id.Id);
         Assert.Equal(1, collector.Count);
 
         collector.Clear();
         ConstructorVariationsTestExtensions.M2(logger, "Two");
         Assert.Null(collector.LatestRecord.Exception);
         Assert.Equal(string.Empty, collector.LatestRecord.Message);
         Assert.Equal(LogLevel.Debug, collector.LatestRecord.Level);
-        Assert.Equal(0, collector.LatestRecord.Id.Id);
+        Assert.NotEqual(0, collector.LatestRecord.Id.Id);
         Assert.Equal(1, collector.Count);
 
         collector.Clear();
         ConstructorVariationsTestExtensions.M3(logger, LogLevel.Error, "Three");
         Assert.Null(collector.LatestRecord.Exception);
         Assert.Equal(string.Empty, collector.LatestRecord.Message);
         Assert.Equal(LogLevel.Error, collector.LatestRecord.Level);
-        Assert.Equal(0, collector.LatestRecord.Id.Id);
+        Assert.NotEqual(0, collector.LatestRecord.Id.Id);
         Assert.Equal(1, collector.Count);
 
         collector.Clear();
         ConstructorVariationsTestExtensions.M4(logger, "Four");
         Assert.Null(collector.LatestRecord.Exception);
         Assert.Equal("M4 Four", collector.LatestRecord.Message);
         Assert.Equal(LogLevel.Debug, collector.LatestRecord.Level);
-        Assert.Equal(0, collector.LatestRecord.Id.Id);
+        Assert.NotEqual(0, collector.LatestRecord.Id.Id);
         Assert.Equal(1, collector.Count);
 
         collector.Clear();
         ConstructorVariationsTestExtensions.M5(logger, LogLevel.Error, "Five");
         Assert.Null(collector.LatestRecord.Exception);
         Assert.Equal("M5 Five", collector.LatestRecord.Message);
         Assert.Equal(LogLevel.Error, collector.LatestRecord.Level);
-        Assert.Equal(0, collector.LatestRecord.Id.Id);
+        Assert.NotEqual(0, collector.LatestRecord.Id.Id);
         Assert.Equal(1, collector.Count);
 
         collector.Clear();
         ConstructorVariationsTestExtensions.M6(logger, "Six");
         Assert.Null(collector.LatestRecord.Exception);
         Assert.Equal(string.Empty, collector.LatestRecord.Message);
         Assert.Equal(LogLevel.Debug, collector.LatestRecord.Level);
-        Assert.Equal(0, collector.LatestRecord.Id.Id);
+        Assert.NotEqual(0, collector.LatestRecord.Id.Id);
         Assert.Equal(1, collector.Count);
 
         collector.Clear();
@@ -282,7 +282,7 @@ public void ConstructorVariationsTests()
         Assert.Null(logRecord.Exception);
         Assert.Equal(string.Empty, logRecord.Message);
         Assert.Equal(LogLevel.Information, logRecord.Level);
-        Assert.Equal(0, logRecord.Id.Id);
+        Assert.NotEqual(0, logRecord.Id.Id);
         Assert.Equal("M7", logRecord.Id.Name);
 
         collector.Clear();
@@ -336,15 +336,15 @@ public void MessageTests()
         Assert.Null(collector.LatestRecord.Exception);
         Assert.Equal("\"p\" -> \"q\"", collector.LatestRecord.Message);
         Assert.Equal(LogLevel.Warning, collector.LatestRecord.Level);
-        Assert.Equal(0, collector.LatestRecord.Id.Id);
+        Assert.NotEqual(0, collector.LatestRecord.Id.Id);
         Assert.Equal(1, collector.Count);
 
         collector.Clear();
         MessageTestExtensions.M7(logger);
         Assert.Null(collector.LatestRecord.Exception);
         Assert.Equal("\"\n\r\\", collector.LatestRecord.Message);
         Assert.Equal(LogLevel.Debug, collector.LatestRecord.Level);
-        Assert.Equal(0, collector.LatestRecord.Id.Id);
+        Assert.NotEqual(0, collector.LatestRecord.Id.Id);
         Assert.Equal(1, collector.Count);
     }
 
@@ -575,7 +575,7 @@ public void EventNameTests()
         Assert.Null(logRecord.Exception);
         Assert.Equal(string.Empty, logRecord.Message);
         Assert.Equal(LogLevel.Warning, logRecord.Level);
-        Assert.Equal(0, logRecord.Id.Id);
+        Assert.NotEqual(0, logRecord.Id.Id);
         Assert.Equal("M1_Event", logRecord.Id.Name);
     }
 

test/Generators/Microsoft.Gen.Logging/Generated/LogPropertiesTests.cs

@@ -431,7 +431,7 @@ public void LogPropertiesDefaultAttrCtor()
         Assert.Equal(1, _logger.Collector.Count);
         var latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Critical, latestRecord.Level);
         Assert.Equal(string.Empty, latestRecord.Message);
 
@@ -482,7 +482,7 @@ public void LogPropertiesRecordClassArgument()
         Assert.Equal(1, _logger.Collector.Count);
         var latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Debug, latestRecord.Level);
         Assert.Empty(latestRecord.Message);
 
@@ -507,7 +507,7 @@ public void LogPropertiesRecordStructArgument()
         Assert.Equal(1, _logger.Collector.Count);
         var latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Debug, latestRecord.Level);
         Assert.Equal($"Struct is: {recordToLog}", latestRecord.Message);
 
@@ -533,7 +533,7 @@ public void LogPropertiesReadonlyRecordStructArgument()
         Assert.Equal(1, _logger.Collector.Count);
         var latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Debug, latestRecord.Level);
         Assert.Equal($"Readonly struct is: {recordToLog}", latestRecord.Message);
 

test/Generators/Microsoft.Gen.Logging/Generated/TagProviderTests.cs

@@ -80,7 +80,7 @@ public void LogsWhenDefaultAttrCtorInNonStaticClass()
         Assert.Equal(1, _logger.Collector.Count);
         var latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Debug, latestRecord.Level);
         Assert.Equal(string.Empty, latestRecord.Message);
 
@@ -103,7 +103,7 @@ public void LogsWhenDefaultAttrCtorInStaticClass()
         Assert.Equal(1, _logger.Collector.Count);
         var latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Trace, latestRecord.Level);
         Assert.Equal(string.Empty, latestRecord.Message);
 
@@ -124,7 +124,7 @@ public void LogsWithNullable()
         Assert.Equal(1, _logger.Collector.Count);
         var latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Trace, latestRecord.Level);
         Assert.Equal(string.Empty, latestRecord.Message);
         Assert.Empty(latestRecord.StructuredState!);
@@ -135,7 +135,7 @@ public void LogsWithNullable()
         Assert.Equal(1, _logger.Collector.Count);
         latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Trace, latestRecord.Level);
         Assert.Equal(string.Empty, latestRecord.Message);
 
@@ -185,7 +185,7 @@ public void LogsWhenOmitParamNameIsTrueWithDefaultAttrCtor()
         Assert.Equal(1, _logger.Collector.Count);
         var latestRecord = _logger.Collector.LatestRecord;
         Assert.Null(latestRecord.Exception);
-        Assert.Equal(0, latestRecord.Id.Id);
+        Assert.NotEqual(0, latestRecord.Id.Id);
         Assert.Equal(LogLevel.Error, latestRecord.Level);
         Assert.Equal(string.Empty, latestRecord.Message);
 
@@ -300,6 +300,26 @@ public void LogsWhenInterface()
         latestRecord.StructuredState.Should().NotBeNull().And.Equal(expectedState);
     }
 
+    [Fact]
+    public void LogsWhenEnumerable()
+    {
+        var a = new[] { "Zero", "One", "Two" };
+        TagProviderExtensions.Enumerable(_logger, LogLevel.Debug, a);
+
+        Assert.Equal(1, _logger.Collector.Count);
+        var latestRecord = _logger.Collector.LatestRecord;
+        Assert.Equal(LogLevel.Debug, latestRecord.Level);
+
+        var expectedState = new Dictionary<string, string?>
+        {
+            ["things.Foo0"] = a[0],
+            ["things.Foo1"] = a[1],
+            ["things.Foo2"] = a[2],
+        };
+
+        latestRecord.StructuredState.Should().NotBeNull().And.Equal(expectedState);
+    }
+
     [Fact]
     public void LogsWhenProviderCombinedWithLogProperties()
     {

test/Generators/Microsoft.Gen.Logging/TestClasses/TagProviderExtensions.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Generic;
 using Microsoft.Extensions.Logging;
 using Microsoft.Shared.Text;
 
@@ -49,6 +50,12 @@ internal static partial void Nullable(
             ILogger logger,
             LogLevel level,
             [TagProvider(typeof(CustomProvider), nameof(CustomProvider.ProvideTags))] int? param);
+
+        [LoggerMessage]
+        internal static partial void Enumerable(
+            ILogger logger,
+            LogLevel level,
+            [TagProvider(typeof(CustomProvider), nameof(CustomProvider.ProvideForEnumerable))] IEnumerable<string> things);
     }
 
     internal static class CustomProvider
@@ -95,6 +102,16 @@ public static void ProvideForInterface(ITagCollector list, IInterfaceToLog param
             list.Add(nameof(ClassToLog.MyIntProperty), param.MyIntProperty);
             list.Add("Custom_property_name", param.MyStringProperty);
         }
+
+        public static void ProvideForEnumerable(ITagCollector list, IEnumerable<string> e)
+        {
+            int i = 0;
+            foreach (var s in e)
+            {
+                list.Add($"Foo{i}", s);
+                i++;
+            }
+        }
     }
 
     internal sealed class ClassToLog