From 44cf6456327286af22158c0df9eeab1efaf0ee7d Mon Sep 17 00:00:00 2001
From: Sam Carlberg <sam@slfc.dev>
Date: Sun, 7 Dec 2025 01:38:10 -0500
Subject: [PATCH] [epilogue] Fix v3 scheduler incompatibility with epilogue
 (#8458)

Was caused by checking assignability like`Protobuf<Scheduler,
ProtoMessage>` instead of `Protobuf<Scheduler, ? extends
ProtoMessage<?>>`

This epilogue bug would have also applied to other protobuf-serializable
types
---
 commandsv3/BUILD.bazel                         |  4 ++++
 commandsv3/build.gradle                        |  2 ++
 .../SchedulerIsLoggableWithEpilogue.java       | 16 ++++++++++++++++
 .../epilogue/processor/ProtobufHandler.java    | 18 +++++++++++-------
 4 files changed, 33 insertions(+), 7 deletions(-)
 create mode 100644 commandsv3/src/test/java/org/wpilib/command3/epilogue/SchedulerIsLoggableWithEpilogue.java

diff --git a/commandsv3/BUILD.bazel b/commandsv3/BUILD.bazel
index c7c41c1750..d3ea907669 100644
--- a/commandsv3/BUILD.bazel
+++ b/commandsv3/BUILD.bazel
@@ -66,8 +66,12 @@ wpilib_java_library(
 wpilib_java_junit5_test(
     name = "commandsv3-java-test",
     srcs = glob(["src/test/java/**/*.java"]),
+    plugins = [
+        "//epilogue-processor:plugin",
+    ],
     deps = [
         ":commandsv3-java",
+        "//epilogue-runtime:epilogue-java",
         "//hal:hal-java",
         "//ntcore:ntcore-java",
         "//wpiannotations",
diff --git a/commandsv3/build.gradle b/commandsv3/build.gradle
index b097060d1d..fe419f7228 100644
--- a/commandsv3/build.gradle
+++ b/commandsv3/build.gradle
@@ -27,7 +27,9 @@ dependencies {
     implementation project(':wpilibj')
     api("us.hebi.quickbuf:quickbuf-runtime:1.4")
     testAnnotationProcessor project(':javacPlugin')
+    testAnnotationProcessor project(':epilogue-processor')
     testImplementation 'org.mockito:mockito-core:4.1.0'
+    testImplementation project(':epilogue-runtime')
 }
 
 sourceSets.main.java.srcDir "${projectDir}/src/generated/main/java"
diff --git a/commandsv3/src/test/java/org/wpilib/command3/epilogue/SchedulerIsLoggableWithEpilogue.java b/commandsv3/src/test/java/org/wpilib/command3/epilogue/SchedulerIsLoggableWithEpilogue.java
new file mode 100644
index 0000000000..e4c07f688f
--- /dev/null
+++ b/commandsv3/src/test/java/org/wpilib/command3/epilogue/SchedulerIsLoggableWithEpilogue.java
@@ -0,0 +1,16 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package org.wpilib.command3.epilogue;
+
+import org.wpilib.command3.Scheduler;
+import org.wpilib.epilogue.Logged;
+
+// This class will fail to compile if m_scheduler is not considered loggable
+// Note that this assumes epilogue is set up correctly.
+@Logged
+public class SchedulerIsLoggableWithEpilogue {
+  @Logged(name = "Scheduler (logged via protobuf)")
+  private final Scheduler m_scheduler = Scheduler.createIndependentScheduler();
+}
diff --git a/epilogue-processor/src/main/java/org/wpilib/epilogue/processor/ProtobufHandler.java b/epilogue-processor/src/main/java/org/wpilib/epilogue/processor/ProtobufHandler.java
index 148e2281c0..664d14a558 100644
--- a/epilogue-processor/src/main/java/org/wpilib/epilogue/processor/ProtobufHandler.java
+++ b/epilogue-processor/src/main/java/org/wpilib/epilogue/processor/ProtobufHandler.java
@@ -58,14 +58,20 @@ public class ProtobufHandler extends ElementHandler {
       return false;
     }
 
-    // eg `Protobuf<Rotation2d, ?>` instead of the raw `Protobuf` type. The message type doesn't
-    // really matter here; we can leave it as a wildcard.
+    // Build a type like `Protobuf<SerializableType, ? extends ProtoMessage<?>>` to match
+    // implementations such as `SchedulerProto implements Protobuf<Scheduler, ProtobufScheduler>`.
+    // Note: Using `ProtoMessage` raw as the upper bound causes assignability to fail; we must use
+    // `ProtoMessage<?>` as the bound, then wrap that with an extends wildcard.
+    var protoMessageElement = m_elementUtils.getTypeElement("us.hebi.quickbuf.ProtoMessage");
+    var protoMessageWildcard =
+        m_typeUtils.getDeclaredType(protoMessageElement, m_typeUtils.getWildcardType(null, null));
+    var boundedProtoMessageWildcard = m_typeUtils.getWildcardType(protoMessageWildcard, null);
+
     var sharpProtobufType =
         m_typeUtils.getDeclaredType(
             m_protobufType,
             typeElement.asType(), // the serializable type
-            m_typeUtils.getWildcardType(
-                m_elementUtils.getTypeElement("us.hebi.quickbuf.ProtoMessage").asType(), null));
+            boundedProtoMessageWildcard);
 
     boolean hasProto =
         typeElement.getEnclosedElements().stream()
@@ -78,9 +84,7 @@ public class ProtobufHandler extends ElementHandler {
                       field
                           .getModifiers()
                           .containsAll(Set.of(Modifier.PUBLIC, Modifier.STATIC, Modifier.FINAL));
-                  var typeMatch =
-                      m_typeUtils.isAssignable(
-                          m_typeUtils.erasure(field.asType()), sharpProtobufType);
+                  var typeMatch = m_typeUtils.isAssignable(field.asType(), sharpProtobufType);
                   return nameMatch && modifiersMatch && typeMatch;
                 });
     return m_typeUtils.isAssignable(type, m_serializable) && hasProto;