Performance degradation with lombok by snjeza · Pull Request #4713 · eclipse-jdt/eclipse.jdt.core

snjeza · 2025-12-23T16:20:05Z

Fixes #4712

iloveeclipse · 2025-12-23T16:30:05Z

Could you please provide a regression test?

snjeza · 2025-12-23T19:05:01Z

Could you please provide a regression test?

Can I start tests with the -javaagent VM argument?

iloveeclipse · 2025-12-23T19:07:54Z

Can I start tests with the -javaagent VM argument?

Should be possible to start JVM from the test with extra arguments, the tests itself don't have individual configurations AFAIK.

snjeza · 2025-12-23T19:15:34Z

@iloveeclipse ~~I will try to create a test.~~

snjeza · 2025-12-30T23:50:53Z

Could you please provide a regression test?

@iloveeclipse I have added ASTConverter18Test.testIssue4712()

eclipse-jdt-bot · 2026-02-28T00:14:51Z

This pull request changes some projects for the first time in this development cycle.
Therefore the following files need a version increment:

org.eclipse.jdt.core.compiler.batch/META-INF/MANIFEST.MF
org.eclipse.jdt.core.compiler.batch/pom.xml
org.eclipse.jdt.core.tests.model/META-INF/MANIFEST.MF
org.eclipse.jdt.core.tests.model/pom.xml
org.eclipse.jdt.core/META-INF/MANIFEST.MF
org.eclipse.jdt.core/pom.xml

An additional commit containing all the necessary changes was pushed to the top of this PR's branch. To obtain these changes (for example if you want to push more changes) either fetch from your fork or apply the git patch.

Git patch

From b1db6ac2c7ef67b78cafc5c6c22dfdefd0f9e153 Mon Sep 17 00:00:00 2001
From: Eclipse JDT Bot <jdt-bot@eclipse.org>
Date: Sat, 28 Feb 2026 00:14:25 +0000
Subject: [PATCH] Version bump(s) for 4.40 stream


diff --git a/org.eclipse.jdt.core.compiler.batch/META-INF/MANIFEST.MF b/org.eclipse.jdt.core.compiler.batch/META-INF/MANIFEST.MF
index 915d7eef49..f1e166fde4 100644
--- a/org.eclipse.jdt.core.compiler.batch/META-INF/MANIFEST.MF
+++ b/org.eclipse.jdt.core.compiler.batch/META-INF/MANIFEST.MF
@@ -3,7 +3,7 @@ Main-Class: org.eclipse.jdt.internal.compiler.batch.Main
 Bundle-ManifestVersion: 2
 Bundle-Name: Eclipse Compiler for Java(TM)
 Bundle-SymbolicName: org.eclipse.jdt.core.compiler.batch
-Bundle-Version: 3.45.0.qualifier
+Bundle-Version: 3.45.100.qualifier
 Bundle-ClassPath: .
 Bundle-Vendor: Eclipse.org
 Automatic-Module-Name: org.eclipse.jdt.core.compiler.batch
diff --git a/org.eclipse.jdt.core.compiler.batch/pom.xml b/org.eclipse.jdt.core.compiler.batch/pom.xml
index ce59619b2e..f0801f9261 100644
--- a/org.eclipse.jdt.core.compiler.batch/pom.xml
+++ b/org.eclipse.jdt.core.compiler.batch/pom.xml
@@ -17,7 +17,7 @@
     <version>4.40.0-SNAPSHOT</version>
   </parent>
   <artifactId>org.eclipse.jdt.core.compiler.batch</artifactId>
-  <version>3.45.0-SNAPSHOT</version>
+  <version>3.45.100-SNAPSHOT</version>
   <packaging>eclipse-plugin</packaging>
 
   <properties>
diff --git a/org.eclipse.jdt.core.tests.model/META-INF/MANIFEST.MF b/org.eclipse.jdt.core.tests.model/META-INF/MANIFEST.MF
index aa5c6b00cf..b7e54e66b3 100644
--- a/org.eclipse.jdt.core.tests.model/META-INF/MANIFEST.MF
+++ b/org.eclipse.jdt.core.tests.model/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.jdt.core.tests.model;singleton:=true
-Bundle-Version: 3.13.700.qualifier
+Bundle-Version: 3.13.800.qualifier
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
 Export-Package: org.eclipse.jdt.core.tests,
diff --git a/org.eclipse.jdt.core.tests.model/pom.xml b/org.eclipse.jdt.core.tests.model/pom.xml
index 543b2b5542..9a5f15b809 100644
--- a/org.eclipse.jdt.core.tests.model/pom.xml
+++ b/org.eclipse.jdt.core.tests.model/pom.xml
@@ -19,7 +19,7 @@
     <relativePath>../tests-pom/</relativePath>
   </parent>
   <artifactId>org.eclipse.jdt.core.tests.model</artifactId>
-  <version>3.13.700-SNAPSHOT</version>
+  <version>3.13.800-SNAPSHOT</version>
   <packaging>eclipse-test-plugin</packaging>
 
   <properties>
diff --git a/org.eclipse.jdt.core/META-INF/MANIFEST.MF b/org.eclipse.jdt.core/META-INF/MANIFEST.MF
index 349cfc604c..a2de32def2 100644
--- a/org.eclipse.jdt.core/META-INF/MANIFEST.MF
+++ b/org.eclipse.jdt.core/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.jdt.core; singleton:=true
-Bundle-Version: 3.45.0.qualifier
+Bundle-Version: 3.45.100.qualifier
 Bundle-Activator: org.eclipse.jdt.core.JavaCore
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
diff --git a/org.eclipse.jdt.core/pom.xml b/org.eclipse.jdt.core/pom.xml
index d3e8348cb1..49fe6a292a 100644
--- a/org.eclipse.jdt.core/pom.xml
+++ b/org.eclipse.jdt.core/pom.xml
@@ -17,7 +17,7 @@
     <version>4.40.0-SNAPSHOT</version>
   </parent>
   <artifactId>org.eclipse.jdt.core</artifactId>
-  <version>3.45.0-SNAPSHOT</version>
+  <version>3.45.100-SNAPSHOT</version>
   <packaging>eclipse-plugin</packaging>
 
   <properties>
-- 
2.53.0

Further information are available in Common Build Issues - Missing version increments.

iloveeclipse · 2026-03-02T20:12:35Z

I've just rebased on master

Copilot

Pull request overview

Addresses Eclipse JDT issue #4712 (“Performance degradation with lombok”) by avoiding expensive comment-mapping/scanning work when the AST contains synthetic/generated nodes with invalid/empty source ranges, and by tightening comment-mapper initialization.

Changes:

Skip visiting/comment-mapping for generated AST nodes (and generated siblings) in DefaultCommentMapper.
Avoid initializing DefaultCommentMapper when the compilation unit has no comments.
Add a regression test covering the reported scenario and harden the scanner against negative positions.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
`org.eclipse.jdt.core/dom/org/eclipse/jdt/core/dom/DefaultCommentMapper.java`	Skips generated nodes/siblings during comment mapping to prevent pathological scanning behavior.
`org.eclipse.jdt.core/dom/org/eclipse/jdt/core/dom/CompilationUnit.java`	Only initializes the comment mapper when there are actual comments to map.
`org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/dom/ASTConverter18Test.java`	Adds a regression test for issue #4712 (currently includes a time-based assertion).
`org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/parser/Scanner.java`	Guards scanning against negative `currentPosition` after an `IndexOutOfBoundsException`.

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Copilot · 2026-03-02T20:19:52Z

+		// The convertCompilationUnit method would need to take less than one second to complete.
+		assertTrue((System.currentTimeMillis() - start) < 1000);


This test asserts a hard 1s wall-clock limit for AST.convertCompilationUnit(), which is likely to be flaky on slower/loaded CI agents and can cause unrelated failures. Consider replacing the time-based assertion with a deterministic functional assertion (e.g., verify comment mapping behavior for generated nodes) or moving this into the existing performance test infrastructure / using a much more resilient threshold with clear skip/assumption rules for slow environments.

AST.convertCompilationUnit() takes less than 20 ms.

snjeza force-pushed the issue-4712 branch from 7eb066d to 3381929 Compare December 30, 2025 23:47

snjeza force-pushed the issue-4712 branch from 3381929 to 16ba92c Compare February 28, 2026 00:10

Performance degradation with lombok

8cb5562

iloveeclipse force-pushed the issue-4712 branch from a50270a to 8cb5562 Compare March 2, 2026 20:12

iloveeclipse requested a review from Copilot March 2, 2026 20:12

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Performance degradation with lombok#4713

Performance degradation with lombok#4713
snjeza wants to merge 1 commit intoeclipse-jdt:masterfrom
snjeza:issue-4712

snjeza commented Dec 23, 2025

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snjeza commented Dec 23, 2025 •

edited

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		// The convertCompilationUnit method would need to take less than one second to complete.
		assertTrue((System.currentTimeMillis() - start) < 1000);

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snjeza commented Dec 23, 2025

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snjeza commented Dec 23, 2025 •

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