[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;