Revert "[DDS] Make runDartDevelopmentServiceFromCLI use IPv6 to serve DDS if either the VM Service address or the bind address cannot be resolved to an IPv4 address"

This reverts commit 4391ca6.

Reason for revert: breaks internal tests

Original change's description:
> [DDS] Make runDartDevelopmentServiceFromCLI use IPv6 to serve DDS if either the VM Service address or the bind address cannot be resolved to an IPv4 address
>
> TEST=CI
>
> Fixes: #56557
> Change-Id: Id06532aedf26d8d5e4d037df72dece2d6550e694
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/389521
> Reviewed-by: Ben Konyi <[email protected]>
> Commit-Queue: Derek Xu <[email protected]>

Change-Id: I02709235d32abab122b5269a5d80f12c4085988b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/390542
Bot-Commit: Rubber Stamper <[email protected]>
Commit-Queue: Derek Xu <[email protected]>
Reviewed-by: Siva Annamalai <[email protected]>

Author: derekxu16

pkg/dds/lib/src/dds_cli_entrypoint.dart

@@ -49,33 +49,18 @@ ${argParser.usage}
     return;
   }
 
-  // Check if the remote VM Service address can be resolved to an IPv4 address.
+  // This URI is provided by the VM service directly so don't bother doing a
+  // lookup.
   final remoteVmServiceUri = Uri.parse(
     argResults[DartDevelopmentServiceOptions.vmServiceUriOption],
   );
-  bool doesVmServiceAddressResolveToIpv4Address = false;
-  try {
-    final addresses = await InternetAddress.lookup(remoteVmServiceUri.host);
-    for (final address in addresses) {
-      if (address.type == InternetAddressType.IPv4) {
-        doesVmServiceAddressResolveToIpv4Address = true;
-      }
-    }
-  } on SocketException catch (e, st) {
-    writeErrorResponse(
-      'Invalid --${DartDevelopmentServiceOptions.vmServiceUriOption} argument: '
-      '$remoteVmServiceUri',
-      st,
-    );
-    return;
-  }
 
   // Ensure that the bind address, which is potentially provided by the user,
   // can be resolved at all, and check whether it can be resolved to an IPv4
   // address.
+  bool doesBindAddressResolveToIpv4Address = false;
   final bindAddress =
       argResults[DartDevelopmentServiceOptions.bindAddressOption];
-  bool doesBindAddressResolveToIpv4Address = false;
   try {
     final addresses = await InternetAddress.lookup(bindAddress);
     for (final address in addresses) {
@@ -130,10 +115,9 @@ ${argParser.usage}
       remoteVmServiceUri,
       serviceUri: serviceUri,
       enableAuthCodes: !disableServiceAuthCodes,
-      // Only use IPv6 to serve DDS if either the remote VM Service address or
-      // the bind address cannot be resolved to an IPv4 address.
-      ipv6: !doesVmServiceAddressResolveToIpv4Address ||
-          !doesBindAddressResolveToIpv4Address,
+      // Only use IPv6 to serve DDS if the bind address cannot be resolved to an
+      // IPv4 address.
+      ipv6: !doesBindAddressResolveToIpv4Address,
       devToolsConfiguration: serveDevTools && devToolsBuildDirectory != null
           ? DevToolsConfiguration(
               enable: serveDevTools,

pkg/dds/test/dap/integration/debug_attach_test.dart

@@ -128,7 +128,10 @@ main() {
 
       expect(
         outputEvents.map((e) => e.output).join(),
-        contains('Invalid --vm-service-uri argument: http://bogus.local'),
+        allOf(
+          contains('Failed to start DDS for ws://bogus.local/'),
+          contains('Failed host lookup'),
+        ),
       );
     });