From 467e518e4689426b2a99eac32fee86b76788d9d2 Mon Sep 17 00:00:00 2001
From: Lauri Tulmin <ltulmin@splunk.com>
Date: Mon, 30 Mar 2026 15:30:23 +0300
Subject: [PATCH] Decompose dicjunction matchers

---
 .../agent/builder/AgentBuilderUtil.java       | 58 +++++++++++++++----
 1 file changed, 47 insertions(+), 11 deletions(-)

diff --git a/javaagent-tooling/src/main/java/net/bytebuddy/agent/builder/AgentBuilderUtil.java b/javaagent-tooling/src/main/java/net/bytebuddy/agent/builder/AgentBuilderUtil.java
index 82df2dd6b5f9..e6ccfbce6561 100644
--- a/javaagent-tooling/src/main/java/net/bytebuddy/agent/builder/AgentBuilderUtil.java
+++ b/javaagent-tooling/src/main/java/net/bytebuddy/agent/builder/AgentBuilderUtil.java
@@ -6,6 +6,7 @@
 package net.bytebuddy.agent.builder;
 
 import static java.util.Collections.emptyIterator;
+import static java.util.Collections.singleton;
 import static java.util.logging.Level.FINE;
 
 import io.opentelemetry.javaagent.extension.matcher.internal.DelegatingMatcher;
@@ -48,6 +49,8 @@ public class AgentBuilderUtil {
   private static final Field erasureMatcherField = getField(ErasureMatcher.class, "matcher");
   private static final Field conjunctionMatchersField =
       getField(ElementMatcher.Junction.Conjunction.class, "matchers");
+  private static final Field disjunctionMatchersField =
+      getField(ElementMatcher.Junction.Disjunction.class, "matchers");
   private static final Field stringMatcherValueField = getField(StringMatcher.class, "value");
   private static final Field stringMatcherModeField = getField(StringMatcher.class, "mode");
   private static final Field stringSetMatcherValuesField =
@@ -173,11 +176,37 @@ private static Result inspect(ElementMatcher<?> matcher) throws Exception {
       List<ElementMatcher<?>> matchers =
           getDelegateMatchers((ElementMatcher.Junction.Conjunction<?>) matcher);
       for (ElementMatcher<?> elementMatcher : matchers) {
+        // For conjunction to match all elements need to match, we can return result for any element
+        // here since we are using it as a negative match - if it does not match the whole matcher
+        // can't match.
         Result result = inspect(elementMatcher);
         if (result != null) {
           return result;
         }
       }
+    } else if (matcher instanceof ElementMatcher.Junction.Disjunction) {
+      List<ElementMatcher<?>> matchers =
+          getDelegateMatchers((ElementMatcher.Junction.Disjunction<?>) matcher);
+      boolean subtype = false;
+      Set<String> names = new HashSet<>();
+      boolean failed = false;
+      for (ElementMatcher<?> elementMatcher : matchers) {
+        // For disjunction to match at least one element needs to match, we need to inspect all
+        // elements and combine results to be able to tell whether the whole matcher could match.
+        Result result = inspect(elementMatcher);
+        if (result == null) {
+          failed = true;
+          break;
+        }
+        // Subtype matcher covers named matcher, if we have at least one subtype matcher we can
+        // treat all named matchers as subtype matchers, if we have only named matchers we can treat
+        // them as named matchers.
+        subtype |= result.subtype;
+        names.addAll(result.names);
+      }
+      if (!failed) {
+        return subtype ? Result.subtype(names) : Result.named(names);
+      }
     }
 
     return null;
@@ -207,19 +236,17 @@ private Result(boolean subtype) {
       this.subtype = subtype;
     }
 
-    private Result() {
-      this(false);
-    }
-
     @Nullable
     static Result subtype(@Nullable Result value) {
       if (value == null) {
         return null;
       }
+      return subtype(value.names);
+    }
 
-      Result result = new Result(true);
-      result.names.addAll(value.names);
-      return result;
+    @Nullable
+    static Result subtype(@Nullable Set<String> value) {
+      return result(true, value);
     }
 
     @Nullable
@@ -227,17 +254,20 @@ static Result named(@Nullable String value) {
       if (value == null) {
         return null;
       }
-      Result result = new Result();
-      result.names.add(value);
-      return result;
+      return named(singleton(value));
     }
 
     @Nullable
     static Result named(@Nullable Set<String> value) {
+      return result(false, value);
+    }
+
+    @Nullable
+    private static Result result(boolean subtype, @Nullable Set<String> value) {
       if (value == null || value.isEmpty()) {
         return null;
       }
-      Result result = new Result();
+      Result result = new Result(subtype);
       result.names.addAll(value);
       return result;
     }
@@ -283,6 +313,12 @@ private static List<ElementMatcher<?>> getDelegateMatchers(
     return (List<ElementMatcher<?>>) conjunctionMatchersField.get(matcher);
   }
 
+  @SuppressWarnings("unchecked") // casting reflection result
+  private static List<ElementMatcher<?>> getDelegateMatchers(
+      ElementMatcher.Junction.Disjunction<?> matcher) throws Exception {
+    return (List<ElementMatcher<?>>) disjunctionMatchersField.get(matcher);
+  }
+
   /**
    * @return the value given string matcher matches when matcher mode is
    *     StringMatcher.Mode.EQUALS_FULLY, null otherwise