Fix proto generation for collection types (NpgsqlPolygon, etc.)

- Add IsCollectionTypeByInterface() to detect types implementing IList<T>, ICollection<T>, IEnumerable<T> - Add GetCollectionElementTypeByInterface() to extract element type from collection interfaces - Add IsCollectionInternalProperty() to filter out Count, Capacity, IsReadOnly, etc. - Update GenerateComplexTypeMessage to generate `repeated T items` for collection types - Filter out indexers (!p.IsIndexer) and collection-internal properties from all property extraction This fixes the invalid proto syntax where C# indexers (this[]) were being generated as proto fields, causing proto compilation errors. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-06 10:33:55 -05:00
parent f76dbb1a97
commit 99aebcf314
2 changed files with 151 additions and 29 deletions
@@ -243,4 +243,97 @@ internal static class ProtoFileTypeMapper
        }
        return null;
    }
+
+    /// <summary>
+    /// Checks if a type is a collection by checking if it implements IList{T}, ICollection{T}, or IEnumerable{T}
+    /// This handles types like NpgsqlPolygon that implement IList{NpgsqlPoint} but aren't named "List"
+    /// </summary>
+    public static bool IsCollectionTypeByInterface(ITypeSymbol typeSymbol)
+    {
+        if (typeSymbol is not INamedTypeSymbol namedType)
+            return false;
+
+        // Skip string (implements IEnumerable<char>)
+        if (namedType.SpecialType == SpecialType.System_String)
+            return false;
+
+        // Check all interfaces for IList<T>, ICollection<T>, or IEnumerable<T>
+        foreach (var iface in namedType.AllInterfaces)
+        {
+            if (iface.IsGenericType && iface.TypeArguments.Length == 1)
+            {
+                var ifaceName = iface.OriginalDefinition.ToDisplayString();
+                if (ifaceName == "System.Collections.Generic.IList<T>" ||
+                    ifaceName == "System.Collections.Generic.ICollection<T>" ||
+                    ifaceName == "System.Collections.Generic.IEnumerable<T>" ||
+                    ifaceName == "System.Collections.Generic.IReadOnlyList<T>" ||
+                    ifaceName == "System.Collections.Generic.IReadOnlyCollection<T>")
+                {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    /// Gets the element type from a collection that implements IList{T}, ICollection{T}, or IEnumerable{T}
+    /// Returns null if the type is not a collection
+    /// </summary>
+    public static ITypeSymbol? GetCollectionElementTypeByInterface(ITypeSymbol typeSymbol)
+    {
+        if (typeSymbol is not INamedTypeSymbol namedType)
+            return null;
+
+        // Skip string
+        if (namedType.SpecialType == SpecialType.System_String)
+            return null;
+
+        // Prefer IList<T> over ICollection<T> over IEnumerable<T>
+        ITypeSymbol? elementType = null;
+        int priority = 0;
+
+        foreach (var iface in namedType.AllInterfaces)
+        {
+            if (iface.IsGenericType && iface.TypeArguments.Length == 1)
+            {
+                var ifaceName = iface.OriginalDefinition.ToDisplayString();
+                int currentPriority = 0;
+
+                if (ifaceName == "System.Collections.Generic.IList<T>" ||
+                    ifaceName == "System.Collections.Generic.IReadOnlyList<T>")
+                    currentPriority = 3;
+                else if (ifaceName == "System.Collections.Generic.ICollection<T>" ||
+                         ifaceName == "System.Collections.Generic.IReadOnlyCollection<T>")
+                    currentPriority = 2;
+                else if (ifaceName == "System.Collections.Generic.IEnumerable<T>")
+                    currentPriority = 1;
+
+                if (currentPriority > priority)
+                {
+                    priority = currentPriority;
+                    elementType = iface.TypeArguments[0];
+                }
+            }
+        }
+
+        return elementType;
+    }
+
+    /// <summary>
+    /// Collection-internal properties that should be skipped when generating proto messages
+    /// </summary>
+    private static readonly System.Collections.Generic.HashSet<string> CollectionInternalProperties = new()
+    {
+        "Count", "Capacity", "IsReadOnly", "IsSynchronized", "SyncRoot", "Keys", "Values"
+    };
+
+    /// <summary>
+    /// Checks if a property name is a collection-internal property that should be skipped
+    /// </summary>
+    public static bool IsCollectionInternalProperty(string propertyName)
+    {
+        return CollectionInternalProperties.Contains(propertyName);
+    }
 }