From 15ebf6c081106bd93b7c1c999b10a0bb0d70f7ff Mon Sep 17 00:00:00 2001
From: carolineRe13 <60150268+carolineRe13@users.noreply.github.com>
Date: Tue, 8 Oct 2024 15:31:05 +0200
Subject: [PATCH 1/2] Allowing namespaces to start with _

Making it possible for namespaces to start with _. This is necessary to use OT exporter as it requires namespace overrides to start with _
---
 src/Generators/Microsoft.Gen.Metrics/Parser.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Generators/Microsoft.Gen.Metrics/Parser.cs b/src/Generators/Microsoft.Gen.Metrics/Parser.cs
index b9d5697e24e..da05c6a51ec 100644
--- a/src/Generators/Microsoft.Gen.Metrics/Parser.cs
+++ b/src/Generators/Microsoft.Gen.Metrics/Parser.cs
@@ -22,7 +22,7 @@ internal sealed class Parser
     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);
+    private static readonly Regex _regexTagNames = new("^[A-Za-z_]+[A-Za-z0-9_.:-]*$", RegexOptions.Compiled);
     private static readonly SymbolDisplayFormat _typeSymbolFormat =
         SymbolDisplayFormat.FullyQualifiedFormat.WithMiscellaneousOptions(
             SymbolDisplayMiscellaneousOptions.IncludeNullableReferenceTypeModifier);

From 17fd8467ac05f4859ce18d8b163867d9d46398a6 Mon Sep 17 00:00:00 2001
From: carolineRe13 <60150268+carolineRe13@users.noreply.github.com>
Date: Wed, 9 Oct 2024 10:28:39 +0200
Subject: [PATCH 2/2] Adding test that checks if a tag can start with _

---
 test/Generators/Microsoft.Gen.Metrics/Unit/ParserTests.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/Generators/Microsoft.Gen.Metrics/Unit/ParserTests.cs b/test/Generators/Microsoft.Gen.Metrics/Unit/ParserTests.cs
index 865315511f6..d6496ac10f3 100644
--- a/test/Generators/Microsoft.Gen.Metrics/Unit/ParserTests.cs
+++ b/test/Generators/Microsoft.Gen.Metrics/Unit/ParserTests.cs
@@ -144,7 +144,7 @@ public async Task ValidDimensionsKeyNames()
         var d = await RunGenerator(@"
             partial class C
             {
-                [Counter(""Env.Name"", ""clustr:region"", ""Req_Name"", ""Req-Status"")]
+                [Counter(""Env.Name"", ""clustr:region"", ""Req_Name"", ""Req-Status"", ""_microsoft_metrics_namespace"")]
                 static partial TestCounter CreateMetricName(Meter meter, string env, string region);
             }");