Minor fix to connect-url to support unix-connect sockets on localhost

lldb/source/Plugins/Platform/gdb-server/PlatformRemoteGDBServer.cpp

@@ -800,7 +800,10 @@ std::string PlatformRemoteGDBServer::MakeUrl(const char *scheme,
                                              const char *hostname,
                                              uint16_t port, const char *path) {
   StreamString result;
-  result.Printf("%s://[%s]", scheme, hostname);
+  result.Printf("%s://", scheme);
+  if (strlen(hostname) > 0)
+    result.Printf("[%s]", hostname);
+
   if (port != 0)
     result.Printf(":%u", port);
   if (path)

lldb/test/API/commands/platform/connect/TestPlatformConnect.py

@@ -57,3 +57,48 @@ def test_platform_process_connect(self):
         self.assertEqual(frame.GetFunction().GetName(), "main")
         self.assertEqual(frame.FindVariable("argc").GetValueAsSigned(), 2)
         process.Continue()
+
+    @skipIfRemote
+    @expectedFailureAll(hostoslist=["windows"], triple=".*-android")
+    @skipIfDarwin  # lldb-server not found correctly
+    @expectedFailureAll(oslist=["windows"])  # process modules not loaded
+    # lldb-server platform times out waiting for the gdbserver port number to be
+    # written to the pipe, yet it seems the gdbserver already has written it.
+    @expectedFailureAll(
+        archs=["aarch64"],
+        oslist=["freebsd"],
+        bugnumber="https://github.com/llvm/llvm-project/issues/84327",
+    )
+    @add_test_categories(["lldb-server"])
+    def test_platform_process_connect_with_unix_connect(self):
+        self.build()
+        lldb_temp_dir = lldb.SBHostOS.GetLLDBPath(lldb.ePathTypeLLDBTempSystemDir)
+        named_pipe = "%s/platform_server.sock" % lldb_temp_dir
+        port_file = self.getBuildArtifact("port")
+        commandline_args = [
+            "platform",
+            "--listen",
+            named_pipe,
+            "--socket-file",
+            port_file,
+            "--",
+            self.getBuildArtifact("a.out"),
+            "foo",
+        ]
+        self.spawnSubprocess(lldbgdbserverutils.get_lldb_server_exe(), commandline_args)
+
+        socket_file = lldbutil.wait_for_file_on_target(self, port_file)
+        new_platform = lldb.SBPlatform("remote-" + self.getPlatform())
+        self.dbg.SetSelectedPlatform(new_platform)
+        connect_url = "unix-connect://%s" % socket_file
+        self.runCmd("platform connect %s" % connect_url)
+
+        lldbutil.run_break_set_by_symbol(self, "main")
+        process = self.process()
+
+        process.Continue()
+
+        frame = self.frame()
+        self.assertEqual(frame.GetFunction().GetName(), "main")
+        self.assertEqual(frame.FindVariable("argc").GetValueAsSigned(), 2)
+        process.Continue()