[endrix]

The Java ELK server bundled ELK 0.8.1 while elkjs was 0.9.3, and the two engines laid some graphs out differently. A diagram could therefore reshuffle its nodes as it grew past the size where layouts move to the server (tracker m1-19).

The source. Only the jar had ever been committed: here, in mlir-viewer, and in ascpp-graph-sprotty, where af9cc65 added the gzip framing.

• Its six classes (io.typefox.elkserver) are recovered with CFR 0.152 into elk-server/, a Maven project (mvn package).
• The logic, wire format and log lines are as the jar had them. That includes the gzip-framed socket mode: GZ10, a 4-byte big-endian length, then a gzip body, in both directions.
• Check: built on ELK 0.8.1, the rebuild lays out the graphs the platform builds for six real documents identically to the 0.2.0 jar, through the platform's own framed client. The six are a chain whose every id holds braces, two grouped specification documents, a 148-node document, and two HDL modules.

The licence. The server stays under the Eclipse Public License 2.0 only, like ELK, and not the GPL secondary licence the rest of the repository is also offered under. elk-server/LICENSE holds the text, every source file carries SPDX-License-Identifier: EPL-2.0, the pom declares the licence, and the build puts it in the jar at META-INF/elk-server/LICENSE, next to the bundled libraries' own notices.

The ELK version. No ELK release matches elkjs 0.9.3:

Pair	Result on the six documents
ELK 0.9.1 jar, elkjs 0.9.3	2 differ
ELK 0.10.0 jar, elkjs 0.9.3	1 differs
ELK 0.9.1 jar, elkjs 0.9.1	2 differ
ELK 0.10.0 jar, elkjs 0.10.0	all 6 identical, node for node and route for route

So the jar is built on ELK 0.10.0 (elk-server-0.3.0-all.jar), and elkjs is pinned to exactly 0.10.0, since a later patch release isn't known to match. SwitchingElk takes elkjs 0.10's generic layout signature.

The guard. test/elk-server-parity.test.ts lays out the graphs the platform builds for two real documents on both engines and requires them to match. The two are a grouped specification document and an HDL module, the two that told the engines apart; they are fixtures under test/fixtures/elk-parity/, with outline, panel text and paths trimmed. The test fails against the old jar, so raising elkjs without rebuilding the jar on the same ELK fails CI.

What changes for users and products

• Small layouts move a little, since elkjs changes from 0.9.3 to 0.10.0. Rendered with the headless renderer, picorv32's trap.md lays out differently but cleanly.
• ELK 0.10 is built for Java 17, so the server now needs Java 17 or later. Without it, layouts stay on elkjs as before. The jar tests skip below Java 17, judged from the Java the process would actually use.
• Products must copy and name elk-server-0.3.0-all.jar. PRs for ndf-ide, sv-ide and vhdl-ide follow and should merge after this one.

Gates. npm run build and check:neutrality pass, and every test passes except the variant wizard's 5-second timeouts, which time out the same way on unchanged main on this machine (load).

https://claude.ai/code/session_01E8WfqKknDNN6xpNVcJL5K8