RFR: 8368675: IGV: nodes are wrongly marked as changed in the difference view

Mon Sep 29 08:42:22 UTC 2025

On Fri, 26 Sep 2025 15:30:49 GMT, Damon Fenacci <dfenacci at openjdk.org> wrote:

>> This changeset refines IGV's node difference analysis to ignore changes in node properties that are derived by IGV, as opposed to generated by HotSpot. Derived properties include the label and color of each node. Ignoring changes in these properties prevents IGV from wrongly marking equal nodes as "changed" (colored in yellow) when showing the difference between two graphs:
>> 
>> <img width="2323" height="651" alt="before-after" src="https://github.com/user-attachments/assets/ea51c86d-4719-45c0-b615-e6e4b8aec023" />
>> 
>> **Testing:** tier1 and manual testing on a few graphs.
>
> src/utils/IdealGraphVisualizer/Data/src/main/java/com/sun/hotspot/igv/data/serialization/Parser.java line 84:
> 
>> 82:     public static final String TO_INDEX_PROPERTY = "toIndex";
>> 83:     public static final String TO_INDEX_ALT_PROPERTY = "index";
>> 84:     public static final String EDGE_LABEL_PROPERTY = "label";
> 
> changed to improve its "expressiveness"?

Yes, just to make it more explicit that this is not the same "label" as node labels.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27515#discussion_r2387147906