Increased the max supported dimensions via source gen to 30 dimensions

src/Generators/Microsoft.Gen.Metrics/Parser.cs

@@ -19,7 +19,7 @@ namespace Microsoft.Gen.Metrics;
 
 internal sealed class Parser
 {
-    private const int MaxTagNames = 20;
+    private const int MaxTagNames = 30;
 
     private static readonly Regex _regex = new("^[A-Z]+[A-za-z0-9]*$", RegexOptions.Compiled);
     private static readonly Regex _regexTagNames = new("^[A-Za-z]+[A-Za-z0-9_.:-]*$", RegexOptions.Compiled);
@@ -450,7 +450,7 @@ private void GetTagDescription(
             IsExtensionMethod = methodSymbol.IsExtensionMethod,
             Modifiers = methodSyntax.Modifiers.ToString(),
             MetricTypeName = methodSymbol.ReturnType.ToDisplayString(), // Roslyn doesn't know this type yet, no need to use a format here
-            StrongTypeConfigs = strongTypeAttrParams.StrongTypeConfigs,
+            StrongTypeConfigs = strongTypeAttrParams.DimensionHashSet,
             StrongTypeObjectName = strongTypeAttrParams.StrongTypeObjectName,
             IsTagTypeClass = strongTypeAttrParams.IsClass,
             MetricTypeModifiers = typeDeclaration.Modifiers.ToString(),
@@ -640,11 +640,11 @@ private StrongTypeAttributeParameters ExtractStrongTypeAttributeParameters(
                 var tagConfigs = BuildTagConfigs(member, typesChain, strongTypeAttributeParameters.TagHashSet,
                     strongTypeAttributeParameters.TagDescriptionDictionary, symbols, _builders.GetStringBuilder());
 
-                strongTypeAttributeParameters.StrongTypeConfigs.AddRange(tagConfigs);
+                strongTypeAttributeParameters.DimensionHashSet.AddRange(tagConfigs);
             }
 
             // Now that all of the current level and below dimensions are extracted, let's get any parent ones
-            strongTypeAttributeParameters.StrongTypeConfigs.AddRange(GetParentTagConfigs(strongTypeSymbol,
+            strongTypeAttributeParameters.DimensionHashSet.AddRange(GetParentTagConfigs(strongTypeSymbol,
                 strongTypeAttributeParameters.TagHashSet, strongTypeAttributeParameters.TagDescriptionDictionary, symbols));
         }
         catch (TransitiveTypeCycleException ex)
@@ -656,7 +656,7 @@ private StrongTypeAttributeParameters ExtractStrongTypeAttributeParameters(
                 ex.NamedType.ToDisplayString());
         }
 
-        if (strongTypeAttributeParameters.StrongTypeConfigs.Count > MaxTagNames)
+        if (strongTypeAttributeParameters.DimensionHashSet.Count > MaxTagNames)
         {
             Diag(DiagDescriptors.ErrorTooManyTagNames, strongTypeSymbol.Locations[0]);
         }

src/Generators/Microsoft.Gen.Metrics/StrongTypeAttributeParameters.cs

@@ -11,7 +11,7 @@ internal sealed class StrongTypeAttributeParameters
     public string MetricNameFromAttribute = string.Empty;
     public HashSet<string> TagHashSet = [];
     public Dictionary<string, string> TagDescriptionDictionary = [];
-    public List<StrongTypeConfig> StrongTypeConfigs = [];
+    public List<StrongTypeConfig> DimensionHashSet = [];
     public string StrongTypeObjectName = string.Empty;
     public bool IsClass;
 }

test/Generators/Microsoft.Gen.Metrics/Unit/ParserTests.Diagnostics.cs

@@ -387,7 +387,7 @@ public async Task TooManyDimensions()
 
         int i = 0;
 
-        for (; i < 21; i++)
+        for (; i < 30; i++)
         {
             sb.AppendLine($"public class C{i} : C{i + 1} {{ public string dim{i} {{get;set;}}}}");
         }

test/Generators/Microsoft.Gen.Metrics/Unit/ParserTests.StrongTypes.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.Text;
 using System.Threading.Tasks;
 using Xunit;
 
@@ -590,4 +591,73 @@ public static partial class MetricClass
 
         Assert.Empty(d);
     }
+
+    [Fact]
+    public async Task MaxDimensions()
+    {
+        StringBuilder sb = new StringBuilder();
+        int i = 1;
+        for (; i < 30; i++)
+        {
+            sb.AppendLine($"public class C{i} : C{i + 1} {{ public string dim{i} {{get;set;}}}}");
+        }
+
+        sb.AppendLine($"public class C{i} {{ public string dim{i} {{get;set;}}}}");
+        sb.AppendLine(@"        public static partial class MetricClass
+        {
+            [Histogram(typeof(C1), Name=""TotalCountTest"")]
+            public static partial TotalCount CreateTotalCountCounter(Meter meter);
+        }");
+        var d = await RunGenerator(sb.ToString());
+        Assert.Empty(d);
+    }
+
+    [Fact]
+    public async Task TransitiveDimensions()
+    {
+        var d = await RunGenerator(@"
+            class MyClassA
+            {
+                public string Dim1 { get; set; }
+                public string Dim2 { get; set; }
+                public string Dim3 { get; set; }
+                public string Dim4 { get; set; }
+                public string Dim5 { get; set; }
+                public string Dim6 { get; set; }
+                public string Dim7 { get; set; }
+                public string Dim8 { get; set; }
+                public string Dim9 { get; set; }
+                public string Dim10 { get; set; }
+                public string Dim11 { get; set; }
+                public string Dim12 { get; set; }
+                public string Dim13 { get; set; }
+                public string Dim14 { get; set; }
+                public string Dim15 { get; set; }
+                public string Dim16 { get; set; }
+                public string Dim17 { get; set; }
+                public string Dim18 { get; set; }
+                public string Dim19 { get; set; }
+                public string Dim20 { get; set; }
+                public MyClassB MyTransitiveProperty { get; set; }
+            }
+            class MyClassB
+            {
+                public string Dim21 { get; set; }
+                public string Dim22 { get; set; }
+                public string Dim23 { get; set; }
+                public string Dim24 { get; set; }
+                public string Dim25 { get; set; }
+                public string Dim26 { get; set; }
+                public string Dim27 { get; set; }
+                public string Dim28 { get; set; }
+                public string Dim29 { get; set; }
+                public string Dim30 { get; set; }
+            }
+            static partial class MetricClass
+            {
+                [Histogram(typeof(MyClassA))]
+                static partial TotalCount CreateTotalCountCounter(Meter meter);
+            }");
+        Assert.Empty(d);
+    }
 }