Allow -u to accept a username string in addition to index, and suppress the User selector even if settings requires it to be shown for one instance only.

src/core/hle/service/acc/profile_manager.cpp

@@ -11,6 +11,7 @@
 #include "common/fs/path_util.h"
 #include "common/polyfill_ranges.h"
 #include "common/settings.h"
+#include "common/string_util.h"
 #include "core/hle/service/acc/profile_manager.h"
 
 namespace Service::Account {
@@ -164,6 +165,22 @@ std::optional<std::size_t> ProfileManager::GetUserIndex(const ProfileInfo& user)
     return GetUserIndex(user.user_uuid);
 }
 
+/// Returns the first user profile seen based on username (which does not enforce uniqueness)
+std::optional<std::size_t> ProfileManager::GetUserIndex(const std::string& username) const {
+    const auto iter =
+        std::find_if(profiles.begin(), profiles.end(), [&username](const ProfileInfo& p) {
+            const std::string pusername = Common::StringFromFixedZeroTerminatedBuffer(
+                reinterpret_cast<const char*>(p.username.data()), p.username.size());
+
+            return username.compare(pusername) == 0;
+        });
+    if (iter == profiles.end()) {
+        return std::nullopt;
+    }
+
+    return static_cast<std::size_t>(std::distance(profiles.begin(), iter));
+}
+
 /// Returns the data structure used by the switch when GetProfileBase is called on acc:*
 bool ProfileManager::GetProfileBase(std::optional<std::size_t> index, ProfileBase& profile) const {
     if (!index || index >= MAX_USERS) {

src/core/hle/service/acc/profile_manager.h

@@ -70,6 +70,7 @@ public:
     std::optional<Common::UUID> GetUser(std::size_t index) const;
     std::optional<std::size_t> GetUserIndex(const Common::UUID& uuid) const;
     std::optional<std::size_t> GetUserIndex(const ProfileInfo& user) const;
+    std::optional<std::size_t> GetUserIndex(const std::string& username) const;
     bool GetProfileBase(std::optional<std::size_t> index, ProfileBase& profile) const;
     bool GetProfileBase(Common::UUID uuid, ProfileBase& profile) const;
     bool GetProfileBase(const ProfileInfo& user, ProfileBase& profile) const;

src/yuzu/main.cpp

@@ -518,20 +518,31 @@ GMainWindow::GMainWindow(std::unique_ptr<QtConfig> config_, bool has_broken_vulk
                 continue;
             }
 
+            int user_arg_idx = ++i;
             bool argument_ok;
-            const std::size_t selected_user = args[++i].toUInt(&argument_ok);
+            std::size_t selected_user = args[user_arg_idx].toUInt(&argument_ok);
 
             if (!argument_ok) {
+                // try to look it up by username, only finds the first username that matches.
+                const std::string user_arg_str = args[user_arg_idx].toStdString();
+                const auto user_idx = system->GetProfileManager().GetUserIndex(user_arg_str);
+
+                if (user_idx == std::nullopt) {
                     LOG_ERROR(Frontend, "Invalid user argument");
                     continue;
                 }
 
+                selected_user = user_idx.value();
+            }
+
             if (!system->GetProfileManager().UserExistsIndex(selected_user)) {
                 LOG_ERROR(Frontend, "Selected user doesn't exist");
                 continue;
             }
 
             Settings::values.current_user = static_cast<s32>(selected_user);
+
+            user_flag_cmd_line = true;
             continue;
         }
 
@@ -1942,7 +1953,7 @@ void GMainWindow::BootGame(const QString& filename, u64 program_id, std::size_t
 
     Settings::LogSettings();
 
-    if (UISettings::values.select_user_on_boot) {
+    if (UISettings::values.select_user_on_boot && !user_flag_cmd_line) {
         const Core::Frontend::ProfileSelectParameters parameters{
             .mode = Service::AM::Applets::UiMode::UserSelector,
             .invalid_uid_list = {},
@@ -1954,6 +1965,11 @@ void GMainWindow::BootGame(const QString& filename, u64 program_id, std::size_t
         }
     }
 
+    // If the user specifies -u (successfully) on the cmd line, don't prompt for a user on first
+    // game startup only. If the user stops emulation and starts a new one, go back to the expected
+    // behavior of asking.
+    user_flag_cmd_line = false;
+
     if (!LoadROM(filename, program_id, program_index, launch_type)) {
         return;
     }

src/yuzu/main.h

@@ -523,6 +523,8 @@ private:
     std::unique_ptr<EmuThread> emu_thread;
     // The path to the game currently running
     QString current_game_path;
+    // Whether a user was set on the command line (skips UserSelector if it's forced to show up)
+    bool user_flag_cmd_line = false;
 
     bool auto_paused = false;
     bool auto_muted = false;