From a3b4a9c7e6d529ff30dd5eddeae7c3ecd4761e22 Mon Sep 17 00:00:00 2001
From: A <a@a.com>
Date: Mon, 6 Jan 2020 22:08:36 +0000
Subject: [PATCH 1/2] Added support for MatchNamesWithUnderscores and ctor
 parameters

---
 Dapper.Tests/MiscTests.cs | 21 +++++++++++++++++++++
 Dapper/DefaultTypeMap.cs  | 15 +++++++++++++--
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/Dapper.Tests/MiscTests.cs b/Dapper.Tests/MiscTests.cs
index 857dcf9a2..2787f0149 100644
--- a/Dapper.Tests/MiscTests.cs
+++ b/Dapper.Tests/MiscTests.cs
@@ -1130,5 +1130,26 @@ private class HazGetOnly
             public int Id { get; }
             public string Name { get; } = "abc";
         }
+
+        [Fact]
+        public void GetOnlyPropertiesWithNonDefaultConstructor()
+        {
+            DefaultTypeMap.MatchNamesWithUnderscores = true;
+            var obj = connection.QuerySingle<HazGetOnlyAndCtor>("select 42 as [id_property], 'def' as [name_property];");
+            Assert.Equal(42, obj.IdProperty);
+            Assert.Equal("def", obj.NameProperty);
+        }
+
+        private class HazGetOnlyAndCtor
+        {
+            public int IdProperty { get; }
+            public string NameProperty { get; }
+
+            public HazGetOnlyAndCtor(int idProperty, string nameProperty)
+            {
+                IdProperty = idProperty;
+                NameProperty = nameProperty;
+            }
+        }
     }
 }
diff --git a/Dapper/DefaultTypeMap.cs b/Dapper/DefaultTypeMap.cs
index 8366ae5ee..bf1b23128 100644
--- a/Dapper/DefaultTypeMap.cs
+++ b/Dapper/DefaultTypeMap.cs
@@ -74,7 +74,8 @@ public ConstructorInfo FindConstructor(string[] names, Type[] types)
                 int i = 0;
                 for (; i < ctorParameters.Length; i++)
                 {
-                    if (!string.Equals(ctorParameters[i].Name, names[i], StringComparison.OrdinalIgnoreCase))
+                    if ((!MatchNamesWithUnderscores && !string.Equals(ctorParameters[i].Name, names[i], StringComparison.OrdinalIgnoreCase)) ||
+                        (MatchNamesWithUnderscores && !string.Equals(ctorParameters[i].Name, names[i].Replace("_", ""), StringComparison.OrdinalIgnoreCase)))
                         break;
                     if (types[i] == typeof(byte[]) && ctorParameters[i].ParameterType.FullName == SqlMapper.LinqBinary)
                         continue;
@@ -121,7 +122,17 @@ public SqlMapper.IMemberMap GetConstructorParameter(ConstructorInfo constructor,
         {
             var parameters = constructor.GetParameters();
 
-            return new SimpleMemberMap(columnName, parameters.FirstOrDefault(p => string.Equals(p.Name, columnName, StringComparison.OrdinalIgnoreCase)));
+            var property = parameters.FirstOrDefault(p => string.Equals(p.Name, columnName, StringComparison.OrdinalIgnoreCase));
+
+            if (property == null && MatchNamesWithUnderscores)
+            {
+                property = parameters.FirstOrDefault(p => string.Equals(p.Name, columnName.Replace("_", ""), StringComparison.Ordinal))
+                    ?? parameters.FirstOrDefault(p => string.Equals(p.Name, columnName.Replace("_", ""), StringComparison.OrdinalIgnoreCase));
+            }
+
+            return new SimpleMemberMap(
+                MatchNamesWithUnderscores ? columnName.Replace("_", "") : columnName,
+                property);
         }
 
         /// <summary>

From ca32340476d630199aec8f930e6984f94599e4f8 Mon Sep 17 00:00:00 2001
From: A <a@a.com>
Date: Tue, 7 Jan 2020 08:02:43 +0000
Subject: [PATCH 2/2] Code reivew changes

---
 Dapper/DefaultTypeMap.cs | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/Dapper/DefaultTypeMap.cs b/Dapper/DefaultTypeMap.cs
index bf1b23128..efa92166a 100644
--- a/Dapper/DefaultTypeMap.cs
+++ b/Dapper/DefaultTypeMap.cs
@@ -122,17 +122,11 @@ public SqlMapper.IMemberMap GetConstructorParameter(ConstructorInfo constructor,
         {
             var parameters = constructor.GetParameters();
 
-            var property = parameters.FirstOrDefault(p => string.Equals(p.Name, columnName, StringComparison.OrdinalIgnoreCase));
+            var effectiveColumnName = MatchNamesWithUnderscores ? columnName.Replace("_", "") : columnName;
 
-            if (property == null && MatchNamesWithUnderscores)
-            {
-                property = parameters.FirstOrDefault(p => string.Equals(p.Name, columnName.Replace("_", ""), StringComparison.Ordinal))
-                    ?? parameters.FirstOrDefault(p => string.Equals(p.Name, columnName.Replace("_", ""), StringComparison.OrdinalIgnoreCase));
-            }
+            var property = parameters.FirstOrDefault(p => string.Equals(p.Name, effectiveColumnName, StringComparison.OrdinalIgnoreCase));
 
-            return new SimpleMemberMap(
-                MatchNamesWithUnderscores ? columnName.Replace("_", "") : columnName,
-                property);
+            return new SimpleMemberMap(effectiveColumnName, property);
         }
 
         /// <summary>