From 350459fb8a6b9e4cf26e9f6e66d575a180b5caeb Mon Sep 17 00:00:00 2001
From: Michael Haubenwallner <michael.haubenwallner@ssi-schaefer.com>
Date: Wed, 22 Mar 2023 15:36:58 +0100
Subject: [PATCH] ClasspathUpdater: preserve existing entries

Refreshing the classpath does not mean to remove entries that are not
created per the PDE level. Instead, just keep them unchanged.
Also, for existing SOURCE entries, stick to the original path notation,
in order to avoid adding a trailing slash, which might be provided when
recreating classpath from scratch.

Change-Id: Ibd9f356b541336b7b85bf8a95c398894988f5849
---
 .../library/build/util/ClasspathUpdater.java  | 51 ++++++++-----------
 1 file changed, 22 insertions(+), 29 deletions(-)

diff --git a/org.eclipse.tea.library.build/src/org/eclipse/tea/library/build/util/ClasspathUpdater.java b/org.eclipse.tea.library.build/src/org/eclipse/tea/library/build/util/ClasspathUpdater.java
index bf83066..39c66c1 100644
--- a/org.eclipse.tea.library.build/src/org/eclipse/tea/library/build/util/ClasspathUpdater.java
+++ b/org.eclipse.tea.library.build/src/org/eclipse/tea/library/build/util/ClasspathUpdater.java
@@ -11,13 +11,13 @@
 package org.eclipse.tea.library.build.util;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.IPath;
@@ -102,60 +102,53 @@ public void update(TaskingLog console, IProgressMonitor monitor) {
 				// Workaround here merges fresh classpath with the original one.
 				IClasspathEntry[] origCP = JavaCore.create(project).getRawClasspath();
 				IClasspathEntry[] freshCP = ClasspathComputer.getClasspath(project, model, null, true, true);
-				Map<IPath, IClasspathEntry> freshCPofPath = Arrays.stream(freshCP)
-						.collect(Collectors.toMap(e -> keyOf(e), e -> e));
+				Map<IPath, IClasspathEntry> collectedCPofPath = Stream.concat(Stream.of(freshCP), Stream.of(origCP))
+						.collect(Collectors.toMap(e -> keyOf(e), e -> e, (first, dupe) -> first));
 
 				List<IClasspathEntry> mergedCP = new ArrayList<>();
 				for (final IClasspathEntry orig : origCP) {
-					final IClasspathEntry fresh = freshCPofPath.remove(keyOf(orig));
-					if (fresh == null) {
-						continue; // obsolete or redundant: drop
+					final IClasspathEntry collect = collectedCPofPath.remove(keyOf(orig));
+					if (collect == null) {
+						continue; // dupe in the original already
 					}
-					IClasspathEntry merged = fresh;
-					switch (fresh.getEntryKind()) {
+					IClasspathEntry merged = collect;
+					switch (collect.getEntryKind()) {
 					case IClasspathEntry.CPE_LIBRARY:
-						if (fresh.getContentKind() == IPackageFragmentRoot.K_BINARY) {
-							IPath source = sourcePaths.get(fresh.getPath().lastSegment()); // override
+						if (collect.getContentKind() == IPackageFragmentRoot.K_BINARY) {
+							IPath source = sourcePaths.get(collect.getPath().lastSegment()); // override
 							source = source != null ? source : orig.getSourceAttachmentPath(); // current
-							source = source != null ? source : fresh.getSourceAttachmentPath(); // default
-							if (!fresh.equals(orig) || !Objects.equals(fresh.getSourceAttachmentPath(), source)) {
-								merged = JavaCore.newLibraryEntry(orig.getPath(), source, null, orig.getAccessRules(),
-										orig.getExtraAttributes(), orig.isExported());
+							source = source != null ? source : collect.getSourceAttachmentPath(); // default
+							if (!collect.equals(orig) || !Objects.equals(collect.getSourceAttachmentPath(), source)) {
+								merged = JavaCore.newLibraryEntry(collect.getPath(), source, null,
+										orig.getAccessRules(), orig.getExtraAttributes(), orig.isExported());
 							}
 						}
 						break;
 					case IClasspathEntry.CPE_SOURCE:
-						if (!fresh.equals(orig)) {
-							merged = JavaCore.newSourceEntry(fresh.getPath(), orig.getInclusionPatterns(),
-									orig.getExclusionPatterns(), orig.getOutputLocation(), orig.getExtraAttributes());
-						}
+						merged = orig;
 						break;
 					case IClasspathEntry.CPE_CONTAINER:
-						if (!fresh.equals(orig)) {
-							merged = JavaCore.newContainerEntry(fresh.getPath(), orig.getAccessRules(),
+						if (!collect.equals(orig)) {
+							merged = JavaCore.newContainerEntry(collect.getPath(), orig.getAccessRules(),
 									orig.getExtraAttributes(), orig.isExported());
 						}
 						break;
 					case IClasspathEntry.CPE_PROJECT:
-						if (!fresh.equals(orig)) {
-							merged = JavaCore.newProjectEntry(fresh.getPath(), orig.getAccessRules(),
+						if (!collect.equals(orig)) {
+							merged = JavaCore.newProjectEntry(collect.getPath(), orig.getAccessRules(),
 									orig.combineAccessRules(), orig.getExtraAttributes(), orig.isExported());
 						}
 						break;
 					case IClasspathEntry.CPE_VARIABLE:
-						if (!fresh.equals(orig)) {
-							merged = JavaCore.newVariableEntry(fresh.getPath(), fresh.getSourceAttachmentPath(),
-									fresh.getSourceAttachmentRootPath(), fresh.getAccessRules(),
-									fresh.getExtraAttributes(), fresh.isExported());
-						}
+						merged = orig;
 						break;
 					}
 					mergedCP.add(merged);
 				}
 
 				for (IClasspathEntry fresh : freshCP) {
-					if (!freshCPofPath.containsKey(keyOf(fresh))) {
-						continue; // existing one, already added
+					if (collectedCPofPath.remove(keyOf(fresh)) == null) {
+						continue; // not a new one
 					}
 					if (fresh.getEntryKind() == IClasspathEntry.CPE_LIBRARY
 							&& fresh.getContentKind() == IPackageFragmentRoot.K_BINARY) {