fix(trs): consume RefImpl and Jazz TRS feeds #873

berezovskyi · 2026-01-16T22:30:16Z

For RefImpl:

Do not treat a nil base cutoff as a rebase reason if it has been fetched before and had the same rdf:nil value.

This could happen if a server starts with an empty base (legit, afaik) and keeps adding change events to the log, never rebasing on the server side (legit, afaik). The PR prevents an endless rebase loop that continues until the server base becomes non-empty.

For Jazz:

Handle ldp:DirectContainer, not just ldp:Container.

The handling is quite hacky and should be refactored.

Checklist

This PR adds an entry to the CHANGELOG. See https://keepachangelog.com/en/1.0.0/ for instructions. Minor edits are exempt.
This PR was tested on at least one Lyo OSLC server (comment @oslc-bot /test-all if not sure) or adds unit/integration tests.
This PR does NOT break the API
Lint checks pass (run mvn package org.openrewrite.maven:rewrite-maven-plugin:run spotless:apply -DskipTests -P'!enforcer' if not, commit & push)

this could happen if a server starts with an empty base (legit, afaik) and keeps adding change events to the log, never rebasing on the server side (legit, afaik) Signed-off-by: Andrew Berezovskyi <andriib@kth.se>

Copilot

Pull request overview

This pull request fixes a bug in the TRS (Tracked Resource Set) client where a nil base cutoff event was incorrectly treated as a reason to trigger a server rollback exception. The fix enables proper handling of servers that start with an empty base and accumulate change events without performing server-side rebases.

Changes:

Refactored the fetchRemoteChangeLogs method to properly handle null and RDF.nil cutoff events
Changed from a do-while loop to a while loop with clearer control flow
Added upfront checks to determine if all change events should be processed when there's no valid cutoff event

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Copilot · 2026-01-16T22:33:47Z

trs/client/trs-client/src/main/java/org/eclipse/lyo/trs/client/handlers/TrsProviderHandler.java

    private boolean fetchRemoteChangeLogs(ChangeLog currentChangeLog, List<ChangeLog> changeLogs) {
        boolean foundChangeEvent = false;
-        URI previousChangeLog;
-        do {
-            if (currentChangeLog != null) {
-                changeLogs.add(currentChangeLog);
+        if (lastProcessedChangeEventUri == null || RDF.nil.getURI().equals(lastProcessedChangeEventUri.toString())) {
+            foundChangeEvent = true;
+        }
+
+        while (currentChangeLog != null) {
+            changeLogs.add(currentChangeLog);
+            if (lastProcessedChangeEventUri != null && !RDF.nil.getURI().equals(lastProcessedChangeEventUri.toString())) {
                if (ProviderUtil.changeLogContainsEvent(lastProcessedChangeEventUri,
                        currentChangeLog)) {
                    foundChangeEvent = true;
                    break;
                }
-                previousChangeLog = currentChangeLog.getPrevious();
-                currentChangeLog = trsClient.fetchRemoteChangeLog(previousChangeLog);
-            } else {
+            }
+
+            URI previousChangeLog = currentChangeLog.getPrevious();
+            if (previousChangeLog == null || RDF.nil.getURI().equals(previousChangeLog.toString())) {
                break;
            }
-        } while (!RDF.nil.getURI().equals(previousChangeLog.toString()));
+
+            currentChangeLog = trsClient.fetchRemoteChangeLog(previousChangeLog);
+        }
        return foundChangeEvent;
    }


This fix addresses an important scenario where a server starts with an empty base (cutoff event is null or RDF.nil) and adds change events without rebasing. However, there doesn't appear to be test coverage for this specific scenario. Consider adding a test case that verifies the behavior when lastProcessedChangeEventUri is set to RDF.nil (from an empty base) to ensure this fix works correctly and to prevent regression.

Signed-off-by: Andrew Berezovskyi <andriib@kth.se>

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 9 comments.

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trs/client/trs-client/pom.xml

trs/client/trs-client/src/main/java/org/eclipse/lyo/trs/client/handlers/TrsProviderHandler.java

Copilot · 2026-01-23T19:22:56Z

trs/client/trs-client/src/main/java/org/eclipse/lyo/trs/client/handlers/TrsProviderHandler.java

+                if (ProviderUtil.isNilUri(lastProcessedChangeEventUri) && ProviderUtil.isNilUri(previousChangeLog)) {
+                    foundChangeEvent = true;
+                    break;
+                }


The new nil-handling branch in fetchRemoteChangeLogs changes rollback/rebase behavior when both the stored cutoff and the changelog previous link are rdf:nil (or null via isNilUri). There doesn't appear to be a unit test covering this path for TrsProviderHandler (existing tests set cutoffEvent to a non-nil URI). Please add/extend a test that exercises the lastProcessedChangeEventUri == rdf:nil + currentChangeLog.previous == rdf:nil case to prevent regressions.

we already do this for the concurrent provider in ConcurrentTrsProviderHandlerTest - we should unify the logic if possible

...s-client/src/main/java/org/eclipse/lyo/trs/client/handlers/ConcurrentTrsProviderHandler.java

trs/client/trs-client/pom.xml

trs/client/trs-client/src/main/java/org/eclipse/lyo/trs/client/handlers/TrsProviderHandler.java

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

berezovskyi · 2026-01-23T19:34:14Z

trs/client/trs-client/pom.xml

+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-junit-jupiter</artifactId>
+      <version>5.21.0</version>


should be dep-managed

berezovskyi · 2026-01-23T19:34:23Z

trs/client/trs-client/pom.xml

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
+      <version>4.13.2</version>


Mainly due to DirectContainer, the current approach is quite hacky Signed-off-by: Andrew Berezovskyi <andriib@kth.se>

berezovskyi · 2026-01-24T14:17:14Z

trs/client/trs-client/src/main/java/org/eclipse/lyo/trs/client/util/ClientUtil.java

            throws TrsEndpointConfigException, TrsEndpointErrorException, LyoModelException {
        final Response.StatusType responseInfo = response.getStatusInfo();
        final Response.Status.Family httpCodeType = responseInfo.getFamily();
+        log.info("HTTP response status: {} {}", responseInfo.getStatusCode(), responseInfo.getReasonPhrase());


Copilot

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

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Copilot · 2026-01-26T11:08:57Z

trs/client/trs-client/src/main/java/org/eclipse/lyo/trs/client/util/ClientUtil.java

+        Resource containerResource = directContainers.next();
+        log.debug("Found ldp:DirectContainer at {}", containerResource.getURI());
+
+        Base base = new Base();
+        try {
+            base.setAbout(new URI(containerResource.getURI()));
+        } catch (URISyntaxException e) {
+            throw new LyoModelException(e);
+        }
+
+        // Extract cutoffEvent
+        if (containerResource.hasProperty(rdFModel.getProperty(TRS_CUTOFF_EVENT))) {
+            Resource cutoffResource = containerResource.getPropertyResourceValue(
+                rdFModel.getProperty(TRS_CUTOFF_EVENT)
+            );
+            if (cutoffResource != null && cutoffResource.isURIResource()) {
+                try {
+                    base.setCutoffEvent(new URI(cutoffResource.getURI()));
+                } catch (URISyntaxException e) {
+                    throw new LyoModelException(e);
+                }
+            }
+        }
+
+        // Extract members (try both rdfs:member and ldp:member)
+        org.apache.jena.rdf.model.Property memberProp = rdFModel.getProperty(RDFS_MEMBER);
+        if (!containerResource.hasProperty(memberProp)) {
+            memberProp = rdFModel.getProperty(LDP_MEMBER);
+        }
+
+        var memberStmts = containerResource.listProperties(memberProp);
+        while (memberStmts.hasNext()) {
+            var stmt = memberStmts.next();
+            if (stmt.getObject().isURIResource()) {
+                try {
+                    base.getMembers().add(new URI(stmt.getObject().asResource().getURI()));
+                } catch (URISyntaxException e) {
+                    log.warn("Invalid member URI: {}", stmt.getObject());
+                }
+            }
+        }
+
+        log.debug("Extracted Base with {} members from DirectContainer", base.getMembers().size());
+        return base;


containerResource.getURI() can be null if the ldp:DirectContainer subject is a blank node; this will cause a NullPointerException when constructing new URI(...). Consider skipping non-URI resources (e.g., check isURIResource() / getURI()!=null) and continuing to the next match, or returning null with a clear error.

Suggested change

Resource containerResource = directContainers.next();

log.debug("Found ldp:DirectContainer at {}", containerResource.getURI());

Base base = new Base();

try {

base.setAbout(new URI(containerResource.getURI()));

} catch (URISyntaxException e) {

throw new LyoModelException(e);

}

// Extract cutoffEvent

if (containerResource.hasProperty(rdFModel.getProperty(TRS_CUTOFF_EVENT))) {

Resource cutoffResource = containerResource.getPropertyResourceValue(

rdFModel.getProperty(TRS_CUTOFF_EVENT)

);

if (cutoffResource != null && cutoffResource.isURIResource()) {

try {

base.setCutoffEvent(new URI(cutoffResource.getURI()));

} catch (URISyntaxException e) {

throw new LyoModelException(e);

}

}

}

// Extract members (try both rdfs:member and ldp:member)

org.apache.jena.rdf.model.Property memberProp = rdFModel.getProperty(RDFS_MEMBER);

if (!containerResource.hasProperty(memberProp)) {

memberProp = rdFModel.getProperty(LDP_MEMBER);

}

var memberStmts = containerResource.listProperties(memberProp);

while (memberStmts.hasNext()) {

var stmt = memberStmts.next();

if (stmt.getObject().isURIResource()) {

try {

base.getMembers().add(new URI(stmt.getObject().asResource().getURI()));

} catch (URISyntaxException e) {

log.warn("Invalid member URI: {}", stmt.getObject());

}

}

}

log.debug("Extracted Base with {} members from DirectContainer", base.getMembers().size());

return base;

while (directContainers.hasNext()) {

Resource containerResource = directContainers.next();

// Skip DirectContainer subjects that are not URI resources (e.g., blank nodes)

if (!containerResource.isURIResource() || containerResource.getURI() == null) {

log.debug("Skipping non-URI ldp:DirectContainer resource: {}", containerResource);

continue;

}

log.debug("Found ldp:DirectContainer at {}", containerResource.getURI());

Base base = new Base();

try {

base.setAbout(new URI(containerResource.getURI()));

} catch (URISyntaxException e) {

throw new LyoModelException(e);

}

// Extract cutoffEvent

if (containerResource.hasProperty(rdFModel.getProperty(TRS_CUTOFF_EVENT))) {

Resource cutoffResource = containerResource.getPropertyResourceValue(

rdFModel.getProperty(TRS_CUTOFF_EVENT)

);

if (cutoffResource != null && cutoffResource.isURIResource()) {

try {

base.setCutoffEvent(new URI(cutoffResource.getURI()));

} catch (URISyntaxException e) {

throw new LyoModelException(e);

}

}

}

// Extract members (try both rdfs:member and ldp:member)

org.apache.jena.rdf.model.Property memberProp = rdFModel.getProperty(RDFS_MEMBER);

if (!containerResource.hasProperty(memberProp)) {

memberProp = rdFModel.getProperty(LDP_MEMBER);

}

var memberStmts = containerResource.listProperties(memberProp);

while (memberStmts.hasNext()) {

var stmt = memberStmts.next();

if (stmt.getObject().isURIResource()) {

try {

base.getMembers().add(new URI(stmt.getObject().asResource().getURI()));

} catch (URISyntaxException e) {

log.warn("Invalid member URI: {}", stmt.getObject());

}

}

}

log.debug("Extracted Base with {} members from DirectContainer", base.getMembers().size());

return base;

}

log.warn("No ldp:DirectContainer with a URI subject found in RDF model");

return null;

Copilot · 2026-01-26T11:08:58Z

trs/client/trs-client/src/main/java/org/eclipse/lyo/trs/client/util/ClientUtil.java

+        if (!directContainers.hasNext()) {
+            return null;
+        }
+
+        Resource containerResource = directContainers.next();
+        log.debug("Found ldp:DirectContainer at {}", containerResource.getURI());
+
+        Base base = new Base();
+        try {
+            base.setAbout(new URI(containerResource.getURI()));
+        } catch (URISyntaxException e) {
+            throw new LyoModelException(e);
+        }
+
+        // Extract cutoffEvent
+        if (containerResource.hasProperty(rdFModel.getProperty(TRS_CUTOFF_EVENT))) {
+            Resource cutoffResource = containerResource.getPropertyResourceValue(
+                rdFModel.getProperty(TRS_CUTOFF_EVENT)
+            );
+            if (cutoffResource != null && cutoffResource.isURIResource()) {
+                try {
+                    base.setCutoffEvent(new URI(cutoffResource.getURI()));
+                } catch (URISyntaxException e) {
+                    throw new LyoModelException(e);
+                }
+            }
+        }
+
+        // Extract members (try both rdfs:member and ldp:member)
+        org.apache.jena.rdf.model.Property memberProp = rdFModel.getProperty(RDFS_MEMBER);
+        if (!containerResource.hasProperty(memberProp)) {
+            memberProp = rdFModel.getProperty(LDP_MEMBER);
+        }
+
+        var memberStmts = containerResource.listProperties(memberProp);
+        while (memberStmts.hasNext()) {
+            var stmt = memberStmts.next();
+            if (stmt.getObject().isURIResource()) {
+                try {
+                    base.getMembers().add(new URI(stmt.getObject().asResource().getURI()));
+                } catch (URISyntaxException e) {
+                    log.warn("Invalid member URI: {}", stmt.getObject());
+                }
+            }
+        }
+
+        log.debug("Extracted Base with {} members from DirectContainer", base.getMembers().size());
+        return base;


ResIterator/statement iterators from Jena should be closed to avoid resource leaks for some Model implementations. Consider using try/finally (or try-with-resources where applicable) to close directContainers and the memberStmts iterator.

Suggested change

if (!directContainers.hasNext()) {

return null;

}

Resource containerResource = directContainers.next();

log.debug("Found ldp:DirectContainer at {}", containerResource.getURI());

Base base = new Base();

try {

base.setAbout(new URI(containerResource.getURI()));

} catch (URISyntaxException e) {

throw new LyoModelException(e);

}

// Extract cutoffEvent

if (containerResource.hasProperty(rdFModel.getProperty(TRS_CUTOFF_EVENT))) {

Resource cutoffResource = containerResource.getPropertyResourceValue(

rdFModel.getProperty(TRS_CUTOFF_EVENT)

);

if (cutoffResource != null && cutoffResource.isURIResource()) {

try {

base.setCutoffEvent(new URI(cutoffResource.getURI()));

} catch (URISyntaxException e) {

throw new LyoModelException(e);

}

}

}

// Extract members (try both rdfs:member and ldp:member)

org.apache.jena.rdf.model.Property memberProp = rdFModel.getProperty(RDFS_MEMBER);

if (!containerResource.hasProperty(memberProp)) {

memberProp = rdFModel.getProperty(LDP_MEMBER);

}

var memberStmts = containerResource.listProperties(memberProp);

while (memberStmts.hasNext()) {

var stmt = memberStmts.next();

if (stmt.getObject().isURIResource()) {

try {

base.getMembers().add(new URI(stmt.getObject().asResource().getURI()));

} catch (URISyntaxException e) {

log.warn("Invalid member URI: {}", stmt.getObject());

}

}

}

log.debug("Extracted Base with {} members from DirectContainer", base.getMembers().size());

return base;

try {

if (!directContainers.hasNext()) {

return null;

}

Resource containerResource = directContainers.next();

log.debug("Found ldp:DirectContainer at {}", containerResource.getURI());

Base base = new Base();

try {

base.setAbout(new URI(containerResource.getURI()));

} catch (URISyntaxException e) {

throw new LyoModelException(e);

}

// Extract cutoffEvent

if (containerResource.hasProperty(rdFModel.getProperty(TRS_CUTOFF_EVENT))) {

Resource cutoffResource = containerResource.getPropertyResourceValue(

rdFModel.getProperty(TRS_CUTOFF_EVENT)

);

if (cutoffResource != null && cutoffResource.isURIResource()) {

try {

base.setCutoffEvent(new URI(cutoffResource.getURI()));

} catch (URISyntaxException e) {

throw new LyoModelException(e);

}

}

}

// Extract members (try both rdfs:member and ldp:member)

org.apache.jena.rdf.model.Property memberProp = rdFModel.getProperty(RDFS_MEMBER);

if (!containerResource.hasProperty(memberProp)) {

memberProp = rdFModel.getProperty(LDP_MEMBER);

}

var memberStmts = containerResource.listProperties(memberProp);

try {

while (memberStmts.hasNext()) {

var stmt = memberStmts.next();

if (stmt.getObject().isURIResource()) {

try {

base.getMembers().add(new URI(stmt.getObject().asResource().getURI()));

} catch (URISyntaxException e) {

log.warn("Invalid member URI: {}", stmt.getObject());

}

}

}

} finally {

memberStmts.close();

}

log.debug("Extracted Base with {} members from DirectContainer", base.getMembers().size());

return base;

} finally {

directContainers.close();

}

Copilot · 2026-01-26T11:08:58Z

trs/client/trs-client/src/test/java/org/eclipse/lyo/trs/client/util/ClientUtilTest.java

+    private String getFixtureBody(String fixtureName) throws IOException {
+        Path path = Path.of("src/test/resources/fixtures", fixtureName);
+        return Files.readString(path).replace("http://localhost:8080", baseUri);
+    }


This test reads fixtures via Path.of("src/test/resources/..."), which depends on the working directory and can be flaky in IDEs/build tools. Prefer loading fixtures from the classpath (e.g., getResourceAsStream) to make the test environment-independent.

Copilot · 2026-01-26T11:08:58Z

trs/client/trs-client/src/main/java/org/eclipse/lyo/trs/client/util/ClientUtil.java

        final Response.StatusType responseInfo = response.getStatusInfo();
        final Response.Status.Family httpCodeType = responseInfo.getFamily();
+        log.info("HTTP response status: {} {}", responseInfo.getStatusCode(), responseInfo.getReasonPhrase());
+        log.info("HTTP response headers: {}", response.getHeaders());


Logging full HTTP response headers at INFO can leak sensitive data (e.g., Authorization/Cookie) and will be very noisy in production. Consider moving this to DEBUG/TRACE and/or redacting sensitive headers before logging.

Suggested change

log.info("HTTP response headers: {}", response.getHeaders());

log.debug("HTTP response headers: {}", response.getHeaders());

fix: do not treat a nil base cutoff as a rebase reason

fc1f918

this could happen if a server starts with an empty base (legit, afaik) and keeps adding change events to the log, never rebasing on the server side (legit, afaik) Signed-off-by: Andrew Berezovskyi <andriib@kth.se>

berezovskyi requested review from Jad-el-khoury and Copilot and removed request for Copilot January 16, 2026 22:30

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berezovskyi added 2 commits January 17, 2026 19:08

fix: throw on exception

53d3489

Signed-off-by: Andrew Berezovskyi <andriib@kth.se>

fix: rebase issues and logging

cb0e2c0

Signed-off-by: Andrew Berezovskyi <andriib@kth.se>

berezovskyi requested a review from Copilot January 23, 2026 19:15

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Apply suggestions from code review

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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

berezovskyi commented Jan 23, 2026

View reviewed changes

fix: ensure TRS client can consume Jazz TRS server output

ccb92f4

Mainly due to DirectContainer, the current approach is quite hacky Signed-off-by: Andrew Berezovskyi <andriib@kth.se>

berezovskyi changed the title ~~fix: do not treat a nil base cutoff as a rebase reason~~ fix(trs): consume RefImpl and Jazz TRS feeds Jan 24, 2026

berezovskyi commented Jan 24, 2026

View reviewed changes

Merge branch 'master' into trsclient

7dc9594

berezovskyi requested a review from Copilot January 26, 2026 11:03

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berezovskyi mentioned this pull request Jan 28, 2026

TRS base is empty oslc-op/refimpl#493

Open

berezovskyi added 4 commits January 31, 2026 13:07

Merge branch 'master' into trsclient

5e28993

Merge branch 'master' into trsclient

7482c9b

Merge branch 'master' into trsclient

1cc4b84

Merge branch 'master' into trsclient

974ad92

	log.info("HTTP response headers: {}", response.getHeaders());
	log.debug("HTTP response headers: {}", response.getHeaders());

fix(trs): consume RefImpl and Jazz TRS feeds #873

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fix(trs): consume RefImpl and Jazz TRS feeds #873

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berezovskyi commented Jan 16, 2026 •

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