[commands] Revert SubsystemBase deprecation/removal (#5634)

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/PIDSubsystem.java

@@ -14,7 +14,7 @@ import edu.wpi.first.math.controller.PIDController;
  *
  * <p>This class is provided by the NewCommands VendorDep
  */
-public abstract class PIDSubsystem extends Subsystem {
+public abstract class PIDSubsystem extends SubsystemBase {
   protected final PIDController m_controller;
   protected boolean m_enabled;
 

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ProfiledPIDSubsystem.java

@@ -16,7 +16,7 @@ import edu.wpi.first.math.trajectory.TrapezoidProfile;
  *
  * <p>This class is provided by the NewCommands VendorDep
  */
-public abstract class ProfiledPIDSubsystem extends Subsystem {
+public abstract class ProfiledPIDSubsystem extends SubsystemBase {
   protected final ProfiledPIDController m_controller;
   protected boolean m_enabled;
 

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/Subsystem.java

@@ -4,10 +4,6 @@
 
 package edu.wpi.first.wpilibj2.command;
 
-import edu.wpi.first.util.sendable.Sendable;
-import edu.wpi.first.util.sendable.SendableBuilder;
-import edu.wpi.first.util.sendable.SendableRegistry;
-
 /**
  * A robot subsystem. Subsystems are the basic unit of robot organization in the Command-based
  * framework; they encapsulate low-level hardware objects (motor controllers, sensors, etc.) and
@@ -17,34 +13,29 @@ import edu.wpi.first.util.sendable.SendableRegistry;
  * their {@link Command#getRequirements()} method, and resources used within a subsystem should
  * generally remain encapsulated and not be shared by other parts of the robot.
  *
- * <p>Subsystems are automatically registered with the default scheduler in order for the {@link
- * Subsystem#periodic()} method to be called.
+ * <p>Subsystems must be registered with the scheduler with the {@link
+ * CommandScheduler#registerSubsystem(Subsystem...)} method in order for the {@link
+ * Subsystem#periodic()} method to be called. It is recommended that this method be called from the
+ * constructor of users' Subsystem implementations. The {@link SubsystemBase} class offers a simple
+ * base for user implementations that handles this.
  *
  * <p>This class is provided by the NewCommands VendorDep
  */
-public abstract class Subsystem implements Sendable {
-  /** Constructor. */
-  public Subsystem() {
-    String name = this.getClass().getSimpleName();
-    name = name.substring(name.lastIndexOf('.') + 1);
-    SendableRegistry.addLW(this, name, name);
-    CommandScheduler.getInstance().registerSubsystem(this);
-  }
-
+public interface Subsystem {
   /**
    * This method is called periodically by the {@link CommandScheduler}. Useful for updating
    * subsystem-specific state that you don't want to offload to a {@link Command}. Teams should try
    * to be consistent within their own codebases about which responsibilities will be handled by
    * Commands, and which will be handled here.
    */
-  public void periodic() {}
+  default void periodic() {}
 
   /**
    * This method is called periodically by the {@link CommandScheduler}. Useful for updating
    * subsystem-specific state that needs to be maintained for simulations, such as for updating
    * {@link edu.wpi.first.wpilibj.simulation} classes and setting simulated sensor readings.
    */
-  public void simulationPeriodic() {}
+  default void simulationPeriodic() {}
 
   /**
    * Sets the default {@link Command} of the subsystem. The default command will be automatically
@@ -55,7 +46,7 @@ public abstract class Subsystem implements Sendable {
    *
    * @param defaultCommand the default command to associate with this subsystem
    */
-  public void setDefaultCommand(Command defaultCommand) {
+  default void setDefaultCommand(Command defaultCommand) {
     CommandScheduler.getInstance().setDefaultCommand(this, defaultCommand);
   }
 
@@ -63,7 +54,7 @@ public abstract class Subsystem implements Sendable {
    * Removes the default command for the subsystem. This will not cancel the default command if it
    * is currently running.
    */
-  public void removeDefaultCommand() {
+  default void removeDefaultCommand() {
     CommandScheduler.getInstance().removeDefaultCommand(this);
   }
 
@@ -73,7 +64,7 @@ public abstract class Subsystem implements Sendable {
    *
    * @return the default command associated with this subsystem
    */
-  public Command getDefaultCommand() {
+  default Command getDefaultCommand() {
     return CommandScheduler.getInstance().getDefaultCommand(this);
   }
 
@@ -83,51 +74,15 @@ public abstract class Subsystem implements Sendable {
    *
    * @return the scheduled command currently requiring this subsystem
    */
-  public Command getCurrentCommand() {
+  default Command getCurrentCommand() {
     return CommandScheduler.getInstance().requiring(this);
   }
 
-  /**
-   * Gets the name of this Subsystem.
-   *
-   * @return Name
-   */
-  public String getName() {
-    return SendableRegistry.getName(this);
-  }
-
-  /**
-   * Sets the name of this Subsystem.
-   *
-   * @param name name
-   */
-  public void setName(String name) {
-    SendableRegistry.setName(this, name);
-  }
-
-  /**
-   * Gets the subsystem name of this Subsystem.
-   *
-   * @return Subsystem name
-   */
-  public String getSubsystem() {
-    return SendableRegistry.getSubsystem(this);
-  }
-
-  /**
-   * Sets the subsystem name of this Subsystem.
-   *
-   * @param subsystem subsystem name
-   */
-  public void setSubsystem(String subsystem) {
-    SendableRegistry.setSubsystem(this, subsystem);
-  }
-
   /**
    * Registers this subsystem with the {@link CommandScheduler}, allowing its {@link
    * Subsystem#periodic()} method to be called when the scheduler runs.
    */
-  public void register() {
+  default void register() {
     CommandScheduler.getInstance().registerSubsystem(this);
   }
 
@@ -138,7 +93,7 @@ public abstract class Subsystem implements Sendable {
    * @return the command
    * @see InstantCommand
    */
-  public Command runOnce(Runnable action) {
+  default Command runOnce(Runnable action) {
     return Commands.runOnce(action, this);
   }
 
@@ -150,7 +105,7 @@ public abstract class Subsystem implements Sendable {
    * @return the command
    * @see RunCommand
    */
-  public Command run(Runnable action) {
+  default Command run(Runnable action) {
     return Commands.run(action, this);
   }
 
@@ -163,7 +118,7 @@ public abstract class Subsystem implements Sendable {
    * @return the command
    * @see StartEndCommand
    */
-  public Command startEnd(Runnable start, Runnable end) {
+  default Command startEnd(Runnable start, Runnable end) {
     return Commands.startEnd(start, end, this);
   }
 
@@ -175,33 +130,7 @@ public abstract class Subsystem implements Sendable {
    * @param end the action to run on interrupt
    * @return the command
    */
-  public Command runEnd(Runnable run, Runnable end) {
+  default Command runEnd(Runnable run, Runnable end) {
     return Commands.runEnd(run, end, this);
   }
-
-  /**
-   * Associates a {@link Sendable} with this Subsystem. Also update the child's name.
-   *
-   * @param name name to give child
-   * @param child sendable
-   */
-  public void addChild(String name, Sendable child) {
-    SendableRegistry.addLW(child, getSubsystem(), name);
-  }
-
-  @Override
-  public void initSendable(SendableBuilder builder) {
-    builder.setSmartDashboardType("Subsystem");
-
-    builder.addBooleanProperty(".hasDefault", () -> getDefaultCommand() != null, null);
-    builder.addStringProperty(
-        ".default",
-        () -> getDefaultCommand() != null ? getDefaultCommand().getName() : "none",
-        null);
-    builder.addBooleanProperty(".hasCommand", () -> getCurrentCommand() != null, null);
-    builder.addStringProperty(
-        ".command",
-        () -> getCurrentCommand() != null ? getCurrentCommand().getName() : "none",
-        null);
-  }
 }

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/SubsystemBase.java

@@ -4,15 +4,84 @@
 
 package edu.wpi.first.wpilibj2.command;
 
+import edu.wpi.first.util.sendable.Sendable;
+import edu.wpi.first.util.sendable.SendableBuilder;
+import edu.wpi.first.util.sendable.SendableRegistry;
+
 /**
  * A base for subsystems that handles registration in the constructor, and provides a more intuitive
  * method for setting the default command.
  *
  * <p>This class is provided by the NewCommands VendorDep
- *
- * @deprecated All functionality provided by {@link SubsystemBase} has been merged into {@link
- *     Subsystem}. Use {@link Subsystem} instead.
  */
-@Deprecated(since = "2024", forRemoval = true)
-@SuppressWarnings("PMD.AbstractClassWithoutAnyMethod")
-public abstract class SubsystemBase extends Subsystem {}
+public abstract class SubsystemBase implements Subsystem, Sendable {
+  /** Constructor. */
+  public SubsystemBase() {
+    String name = this.getClass().getSimpleName();
+    name = name.substring(name.lastIndexOf('.') + 1);
+    SendableRegistry.addLW(this, name, name);
+    CommandScheduler.getInstance().registerSubsystem(this);
+  }
+
+  /**
+   * Gets the name of this Subsystem.
+   *
+   * @return Name
+   */
+  public String getName() {
+    return SendableRegistry.getName(this);
+  }
+
+  /**
+   * Sets the name of this Subsystem.
+   *
+   * @param name name
+   */
+  public void setName(String name) {
+    SendableRegistry.setName(this, name);
+  }
+
+  /**
+   * Gets the subsystem name of this Subsystem.
+   *
+   * @return Subsystem name
+   */
+  public String getSubsystem() {
+    return SendableRegistry.getSubsystem(this);
+  }
+
+  /**
+   * Sets the subsystem name of this Subsystem.
+   *
+   * @param subsystem subsystem name
+   */
+  public void setSubsystem(String subsystem) {
+    SendableRegistry.setSubsystem(this, subsystem);
+  }
+
+  /**
+   * Associates a {@link Sendable} with this Subsystem. Also update the child's name.
+   *
+   * @param name name to give child
+   * @param child sendable
+   */
+  public void addChild(String name, Sendable child) {
+    SendableRegistry.addLW(child, getSubsystem(), name);
+  }
+
+  @Override
+  public void initSendable(SendableBuilder builder) {
+    builder.setSmartDashboardType("Subsystem");
+
+    builder.addBooleanProperty(".hasDefault", () -> getDefaultCommand() != null, null);
+    builder.addStringProperty(
+        ".default",
+        () -> getDefaultCommand() != null ? getDefaultCommand().getName() : "none",
+        null);
+    builder.addBooleanProperty(".hasCommand", () -> getCurrentCommand() != null, null);
+    builder.addStringProperty(
+        ".command",
+        () -> getCurrentCommand() != null ? getCurrentCommand().getName() : "none",
+        null);
+  }
+}

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/TrapezoidProfileSubsystem.java

@@ -14,7 +14,7 @@ import edu.wpi.first.math.trajectory.TrapezoidProfile;
  *
  * <p>This class is provided by the NewCommands VendorDep
  */
-public abstract class TrapezoidProfileSubsystem extends Subsystem {
+public abstract class TrapezoidProfileSubsystem extends SubsystemBase {
   private final double m_period;
   private final TrapezoidProfile m_profile;
 

wpilibNewCommands/src/main/native/cpp/frc2/command/Subsystem.cpp

@@ -8,12 +8,6 @@
 #include "frc2/command/Commands.h"
 
 using namespace frc2;
-
-Subsystem::Subsystem() {
-  wpi::SendableRegistry::AddLW(this, GetTypeName(*this));
-  CommandScheduler::GetInstance().RegisterSubsystem({this});
-}
-
 Subsystem::~Subsystem() {
   CommandScheduler::GetInstance().UnregisterSubsystem(this);
 }
@@ -39,26 +33,6 @@ Command* Subsystem::GetCurrentCommand() const {
   return CommandScheduler::GetInstance().Requiring(this);
 }
 
-std::string Subsystem::GetName() const {
-  return wpi::SendableRegistry::GetName(this);
-}
-
-void Subsystem::SetName(std::string_view name) {
-  wpi::SendableRegistry::SetName(this, name);
-}
-
-std::string Subsystem::GetSubsystem() const {
-  return wpi::SendableRegistry::GetSubsystem(this);
-}
-
-void Subsystem::SetSubsystem(std::string_view name) {
-  wpi::SendableRegistry::SetSubsystem(this, name);
-}
-
-void Subsystem::AddChild(std::string name, wpi::Sendable* child) {
-  wpi::SendableRegistry::AddLW(child, GetSubsystem(), name);
-}
-
 void Subsystem::Register() {
   return CommandScheduler::GetInstance().RegisterSubsystem(this);
 }
@@ -80,33 +54,3 @@ CommandPtr Subsystem::RunEnd(std::function<void()> run,
                              std::function<void()> end) {
   return cmd::RunEnd(std::move(run), std::move(end), {this});
 }
-
-void Subsystem::InitSendable(wpi::SendableBuilder& builder) {
-  builder.SetSmartDashboardType("Subsystem");
-  builder.AddBooleanProperty(
-      ".hasDefault", [this] { return GetDefaultCommand() != nullptr; },
-      nullptr);
-  builder.AddStringProperty(
-      ".default",
-      [this]() -> std::string {
-        auto command = GetDefaultCommand();
-        if (command == nullptr) {
-          return "none";
-        }
-        return command->GetName();
-      },
-      nullptr);
-  builder.AddBooleanProperty(
-      ".hasCommand", [this] { return GetCurrentCommand() != nullptr; },
-      nullptr);
-  builder.AddStringProperty(
-      ".command",
-      [this]() -> std::string {
-        auto command = GetCurrentCommand();
-        if (command == nullptr) {
-          return "none";
-        }
-        return command->GetName();
-      },
-      nullptr);
-}

wpilibNewCommands/src/main/native/cpp/frc2/command/SubsystemBase.cpp

@@ -12,4 +12,57 @@
 
 using namespace frc2;
 
-SubsystemBase::SubsystemBase() {}
+SubsystemBase::SubsystemBase() {
+  wpi::SendableRegistry::AddLW(this, GetTypeName(*this));
+  CommandScheduler::GetInstance().RegisterSubsystem({this});
+}
+
+void SubsystemBase::InitSendable(wpi::SendableBuilder& builder) {
+  builder.SetSmartDashboardType("Subsystem");
+  builder.AddBooleanProperty(
+      ".hasDefault", [this] { return GetDefaultCommand() != nullptr; },
+      nullptr);
+  builder.AddStringProperty(
+      ".default",
+      [this]() -> std::string {
+        auto command = GetDefaultCommand();
+        if (command == nullptr) {
+          return "none";
+        }
+        return command->GetName();
+      },
+      nullptr);
+  builder.AddBooleanProperty(
+      ".hasCommand", [this] { return GetCurrentCommand() != nullptr; },
+      nullptr);
+  builder.AddStringProperty(
+      ".command",
+      [this]() -> std::string {
+        auto command = GetCurrentCommand();
+        if (command == nullptr) {
+          return "none";
+        }
+        return command->GetName();
+      },
+      nullptr);
+}
+
+std::string SubsystemBase::GetName() const {
+  return wpi::SendableRegistry::GetName(this);
+}
+
+void SubsystemBase::SetName(std::string_view name) {
+  wpi::SendableRegistry::SetName(this, name);
+}
+
+std::string SubsystemBase::GetSubsystem() const {
+  return wpi::SendableRegistry::GetSubsystem(this);
+}
+
+void SubsystemBase::SetSubsystem(std::string_view name) {
+  wpi::SendableRegistry::SetSubsystem(this, name);
+}
+
+void SubsystemBase::AddChild(std::string name, wpi::Sendable* child) {
+  wpi::SendableRegistry::AddLW(child, GetSubsystem(), name);
+}

wpilibNewCommands/src/main/native/include/frc2/command/PIDSubsystem.h

@@ -6,7 +6,7 @@
 
 #include <frc/controller/PIDController.h>
 
-#include "frc2/command/Subsystem.h"
+#include "frc2/command/SubsystemBase.h"
 
 namespace frc2 {
 /**
@@ -17,7 +17,7 @@ namespace frc2 {
  *
  * @see PIDController
  */
-class PIDSubsystem : public Subsystem {
+class PIDSubsystem : public SubsystemBase {
  public:
   /**
    * Creates a new PIDSubsystem.

wpilibNewCommands/src/main/native/include/frc2/command/ProfiledPIDSubsystem.h

@@ -7,7 +7,7 @@
 #include <frc/controller/ProfiledPIDController.h>
 #include <units/time.h>
 
-#include "frc2/command/Subsystem.h"
+#include "frc2/command/SubsystemBase.h"
 
 namespace frc2 {
 /**
@@ -19,7 +19,7 @@ namespace frc2 {
  * @see ProfiledPIDController
  */
 template <class Distance>
-class ProfiledPIDSubsystem : public Subsystem {
+class ProfiledPIDSubsystem : public SubsystemBase {
   using Distance_t = units::unit_t<Distance>;
   using Velocity =
       units::compound_unit<Distance, units::inverse<units::seconds>>;

wpilibNewCommands/src/main/native/include/frc2/command/Subsystem.h

@@ -6,11 +6,8 @@
 
 #include <concepts>
 #include <functional>
-#include <string>
 #include <utility>
 
-#include <wpi/sendable/Sendable.h>
-
 #include "frc2/command/CommandScheduler.h"
 
 namespace frc2 {
@@ -27,19 +24,22 @@ class CommandPtr;
  * subsystem should generally remain encapsulated and not be shared by other
  * parts of the robot.
  *
- * <p>Subsystems are automatically registered with the scheduler with the
+ * <p>Subsystems must be registered with the scheduler with the
  * CommandScheduler.RegisterSubsystem() method in order for the
- * Periodic() method to be called.
+ * Periodic() method to be called.  It is recommended that this method be called
+ * from the constructor of users' Subsystem implementations.  The
+ * SubsystemBase class offers a simple base for user implementations
+ * that handles this.
  *
  * This class is provided by the NewCommands VendorDep
  *
  * @see Command
  * @see CommandScheduler
+ * @see SubsystemBase
  */
-class Subsystem : public wpi::Sendable, public wpi::SendableHelper<Subsystem> {
+class Subsystem {
  public:
-  ~Subsystem() override;
-
+  virtual ~Subsystem();
   /**
    * This method is called periodically by the CommandScheduler.  Useful for
    * updating subsystem-specific state that you don't want to offload to a
@@ -111,43 +111,6 @@ class Subsystem : public wpi::Sendable, public wpi::SendableHelper<Subsystem> {
    */
   void Register();
 
-  /**
-   * Gets the name of this Subsystem.
-   *
-   * @return Name
-   */
-  std::string GetName() const;
-
-  /**
-   * Sets the name of this Subsystem.
-   *
-   * @param name name
-   */
-  void SetName(std::string_view name);
-
-  /**
-   * Gets the subsystem name of this Subsystem.
-   *
-   * @return Subsystem name
-   */
-  std::string GetSubsystem() const;
-
-  /**
-   * Sets the subsystem name of this Subsystem.
-   *
-   * @param name subsystem name
-   */
-  void SetSubsystem(std::string_view name);
-
-  /**
-   * Associate a Sendable with this Subsystem.
-   * Also update the child's name.
-   *
-   * @param name name to give child
-   * @param child sendable
-   */
-  void AddChild(std::string name, wpi::Sendable* child);
-
   /**
    * Constructs a command that runs an action once and finishes. Requires this
    * subsystem.
@@ -185,10 +148,5 @@ class Subsystem : public wpi::Sendable, public wpi::SendableHelper<Subsystem> {
    */
   [[nodiscard]]
   CommandPtr RunEnd(std::function<void()> run, std::function<void()> end);
-
-  void InitSendable(wpi::SendableBuilder& builder) override;
-
- protected:
-  Subsystem();
 };
 }  // namespace frc2

wpilibNewCommands/src/main/native/include/frc2/command/SubsystemBase.h

@@ -4,7 +4,11 @@
 
 #pragma once
 
-#include <wpi/deprecated.h>
+#include <string>
+#include <string_view>
+
+#include <wpi/sendable/Sendable.h>
+#include <wpi/sendable/SendableHelper.h>
 
 #include "frc2/command/Subsystem.h"
 
@@ -14,13 +18,51 @@ namespace frc2 {
  * provides a more intuitive method for setting the default command.
  *
  * This class is provided by the NewCommands VendorDep
- *
- * @deprecated All functionality provided by SubsystemBase has been merged into
- * Subsystem. Use Subsystem instead.
  */
-class [[deprecated("Use Subsystem instead")]] SubsystemBase : public Subsystem {
+class SubsystemBase : public Subsystem,
+                      public wpi::Sendable,
+                      public wpi::SendableHelper<SubsystemBase> {
+ public:
+  void InitSendable(wpi::SendableBuilder& builder) override;
+
+  /**
+   * Gets the name of this Subsystem.
+   *
+   * @return Name
+   */
+  std::string GetName() const;
+
+  /**
+   * Sets the name of this Subsystem.
+   *
+   * @param name name
+   */
+  void SetName(std::string_view name);
+
+  /**
+   * Gets the subsystem name of this Subsystem.
+   *
+   * @return Subsystem name
+   */
+  std::string GetSubsystem() const;
+
+  /**
+   * Sets the subsystem name of this Subsystem.
+   *
+   * @param name subsystem name
+   */
+  void SetSubsystem(std::string_view name);
+
+  /**
+   * Associate a Sendable with this Subsystem.
+   * Also update the child's name.
+   *
+   * @param name name to give child
+   * @param child sendable
+   */
+  void AddChild(std::string name, wpi::Sendable* child);
+
  protected:
-  WPI_DEPRECATED("Use Subsystem instead")
   SubsystemBase();
 };
 }  // namespace frc2

wpilibNewCommands/src/main/native/include/frc2/command/TrapezoidProfileSubsystem.h

@@ -7,7 +7,7 @@
 #include <frc/trajectory/TrapezoidProfile.h>
 #include <units/time.h>
 
-#include "frc2/command/Subsystem.h"
+#include "frc2/command/SubsystemBase.h"
 
 namespace frc2 {
 /**
@@ -18,7 +18,7 @@ namespace frc2 {
  * This class is provided by the NewCommands VendorDep
  */
 template <class Distance>
-class TrapezoidProfileSubsystem : public Subsystem {
+class TrapezoidProfileSubsystem : public SubsystemBase {
   using Distance_t = units::unit_t<Distance>;
   using Velocity =
       units::compound_unit<Distance, units::inverse<units::seconds>>;