Clone connection string builder when building data source (#5000)

(cherry picked from commit 1566d76)
npgsql · Mar 18, 2023 · 5e0141f · 5e0141f
1 parent 7c19344
commit 5e0141f
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Showing 2 changed files with 19 additions and 5 deletions.
diff --git a/src/Npgsql/NpgsqlDataSourceBuilder.cs b/src/Npgsql/NpgsqlDataSourceBuilder.cs
@@ -339,19 +339,20 @@ static string GetPgName(Type clrType, INpgsqlNameTranslator nameTranslator)
     public NpgsqlDataSource Build()
     {
         var config = PrepareConfiguration();
+        var connectionStringBuilder = ConnectionStringBuilder.Clone();
 
         if (ConnectionStringBuilder.Host!.Contains(","))
         {
             ValidateMultiHost();
 
-            return new NpgsqlMultiHostDataSource(ConnectionStringBuilder, config);
+            return new NpgsqlMultiHostDataSource(connectionStringBuilder, config);
         }
 
         return ConnectionStringBuilder.Multiplexing
-            ? new MultiplexingDataSource(ConnectionStringBuilder, config)
+            ? new MultiplexingDataSource(connectionStringBuilder, config)
             : ConnectionStringBuilder.Pooling
-                ? new PoolingDataSource(ConnectionStringBuilder, config)
-                : new UnpooledDataSource(ConnectionStringBuilder, config);
+                ? new PoolingDataSource(connectionStringBuilder, config)
+                : new UnpooledDataSource(connectionStringBuilder, config);
     }
 
     /// <summary>
@@ -363,7 +364,7 @@ public NpgsqlMultiHostDataSource BuildMultiHost()
 
         ValidateMultiHost();
 
-        return new(ConnectionStringBuilder, config);
+        return new(ConnectionStringBuilder.Clone(), config);
     }
 
     NpgsqlDataSourceConfiguration PrepareConfiguration()

diff --git a/test/Npgsql.Tests/DataSourceTests.cs b/test/Npgsql.Tests/DataSourceTests.cs
@@ -280,4 +280,17 @@ public async Task Multiplexing_connectionless_command_open_connection()
         Assert.True(reader.Read());
         Assert.That(reader.GetInt32(0), Is.EqualTo(1));
     }
+
+    [Test]
+    public async Task Connection_string_builder_settings_are_frozen_on_Build()
+    {
+        var builder = CreateDataSourceBuilder();
+        builder.ConnectionStringBuilder.ApplicationName = "foo";
+        await using var dataSource = builder.Build();
+
+        builder.ConnectionStringBuilder.ApplicationName = "bar";
+
+        await using var command = dataSource.CreateCommand("SHOW application_name");
+        Assert.That(await command.ExecuteScalarAsync(), Is.EqualTo("foo"));
+    }
 }