Allow returning non-empty NpgsqlConection.DataSource with closed conn… (#4987)

vonzshik · web-flow · commit 5461fa883c29 · 2023-03-09T19:30:06.000Z
* Allow returning non-empty NpgsqlConection.DataSource with closed connection if single host Closes #4985
diff --git a/src/Npgsql/NpgsqlConnection.cs b/src/Npgsql/NpgsqlConnection.cs
@@ -449,7 +449,7 @@ public override string ConnectionString
     /// The name of the database server (host and port). If the connection uses a Unix-domain socket,
     /// the path to that socket is returned. The default value is the empty string.
     /// </value>
-    public override string DataSource => Connector?.Settings.DataSourceCached ?? string.Empty;
+    public override string DataSource => Connector?.Settings.DataSourceCached ?? _dataSource?.Settings.DataSourceCached ?? string.Empty;
 
     /// <summary>
     /// Whether to use Windows integrated security to log in.
diff --git a/src/Npgsql/NpgsqlConnectionStringBuilder.cs b/src/Npgsql/NpgsqlConnectionStringBuilder.cs
@@ -27,9 +27,9 @@ public sealed partial class NpgsqlConnectionStringBuilder : DbConnectionStringBu
     /// </summary>
     string? _dataSourceCached;
 
-    internal string DataSourceCached
-        => _dataSourceCached ??= _host is null
-            ? string.Empty
+    internal string? DataSourceCached
+        => _dataSourceCached ??= _host is null || _host.Contains(',')
+            ? null
             : IsUnixSocket(_host, _port, out var socketPath, replaceForAbstract: false)
                 ? socketPath
                 : $"tcp://{_host}:{_port}";
diff --git a/test/Npgsql.Tests/ConnectionTests.cs b/test/Npgsql.Tests/ConnectionTests.cs
@@ -500,17 +500,23 @@ public async Task Unix_abstract_domain_socket()
     }
 
     [Test, IssueLink("https://github.com/npgsql/npgsql/issues/903")]
-    public async Task DataSource_property()
+    public void DataSource_property()
     {
         using var conn = new NpgsqlConnection();
         Assert.That(conn.DataSource, Is.EqualTo(string.Empty));
 
-        conn.ConnectionString = ConnectionString;
-        Assert.That(conn.DataSource, Is.EqualTo(string.Empty));
+        var csb = new NpgsqlConnectionStringBuilder(ConnectionString);
 
-        await conn.OpenAsync();
-        await using var _ = await conn.BeginTransactionAsync();
-        Assert.That(conn.DataSource, Is.EqualTo($"tcp://{conn.Host}:{conn.Port}"));
+        conn.ConnectionString = csb.ConnectionString;
+        Assert.That(conn.DataSource, Is.EqualTo($"tcp://{csb.Host}:{csb.Port}"));
+
+        // Multiplexing isn't supported with multiple hosts
+        if (IsMultiplexing)
+            return;
+
+        csb.Host = "127.0.0.1, 127.0.0.2";
+        conn.ConnectionString = csb.ConnectionString;
+        Assert.That(conn.DataSource, Is.EqualTo(string.Empty));
     }
 
     #region Server version
