From 1307f007f53eac5d003fd13004c6fd3abbc48435 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gustaf=20R=C3=A4ntil=C3=A4?= <g.rantila@gmail.com>
Date: Fri, 9 May 2025 17:12:03 +0200
Subject: [PATCH] fix: Missing edges in the catalog-graph plugin
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Signed-off-by: Gustaf Räntilä <g.rantila@gmail.com>
---
 .changeset/some-horses-ask.md                 |  5 ++
 .../useEntityRelationNodesAndEdges.test.ts    | 53 +++++++++++++++++++
 .../useEntityRelationNodesAndEdges.ts         | 41 ++++++++++----
 3 files changed, 89 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/some-horses-ask.md

diff --git a/.changeset/some-horses-ask.md b/.changeset/some-horses-ask.md
new file mode 100644
index 0000000000..2eaabd49f5
--- /dev/null
+++ b/.changeset/some-horses-ask.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-graph': patch
+---
+
+Fix rendering of missing relations
diff --git a/plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.test.ts b/plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.test.ts
index 0a5e43bf37..08b718d789 100644
--- a/plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.test.ts
+++ b/plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.test.ts
@@ -34,6 +34,17 @@ const useEntityRelationGraph = useEntityRelationGraphMocked as jest.Mock<
   ReturnType<typeof useEntityRelationGraphMocked>
 >;
 
+/*
+  This is the full test graph:
+  - b:d/c -> k:d/a1 (ownerOf)
+  - b:d/c -> b:d/c1 (hasPart)
+  - k:d/a1 -> b:d/c (ownedBy)
+  - k:d/a1 -> b:d/c1 (ownedBy)
+  - b:d/c1 -> b:d/c (partOf)
+  - b:d/c1 -> k:d/a1 (ownerOf)
+  - b:d/c1 -> b:d/c2 (hasPart)
+  - b:d/c2 -> b:d/c1 (partOf)
+*/
 const entities: { [ref: string]: Entity } = {
   'b:d/c': {
     apiVersion: 'a',
@@ -233,6 +244,12 @@ describe('useEntityRelationNodesAndEdges', () => {
         relations: [RELATION_HAS_PART, RELATION_PART_OF],
         to: 'b:d/c1',
       },
+      {
+        from: 'b:d/c1',
+        label: 'visible',
+        relations: [RELATION_OWNER_OF, RELATION_OWNED_BY],
+        to: 'k:d/a1',
+      },
       {
         from: 'b:d/c1',
         label: 'visible',
@@ -302,12 +319,42 @@ describe('useEntityRelationNodesAndEdges', () => {
         relations: [RELATION_HAS_PART],
         to: 'b:d/c1',
       },
+      {
+        from: 'b:d/c1',
+        label: 'visible',
+        relations: [RELATION_PART_OF],
+        to: 'b:d/c',
+      },
+      {
+        from: 'b:d/c1',
+        label: 'visible',
+        relations: [RELATION_OWNER_OF],
+        to: 'k:d/a1',
+      },
       {
         from: 'b:d/c1',
         label: 'visible',
         relations: [RELATION_HAS_PART],
         to: 'b:d/c2',
       },
+      {
+        from: 'b:d/c2',
+        label: 'visible',
+        relations: [RELATION_PART_OF],
+        to: 'b:d/c1',
+      },
+      {
+        from: 'k:d/a1',
+        label: 'visible',
+        relations: [RELATION_OWNED_BY],
+        to: 'b:d/c',
+      },
+      {
+        from: 'k:d/a1',
+        label: 'visible',
+        relations: [RELATION_OWNED_BY],
+        to: 'b:d/c1',
+      },
     ]);
   });
 
@@ -549,6 +596,12 @@ describe('useEntityRelationNodesAndEdges', () => {
         relations: ['ownerOf', 'ownedBy'],
         to: 'k:d/a1',
       },
+      {
+        from: 'b:d/c',
+        label: 'visible',
+        relations: ['ownerOf', 'ownedBy'],
+        to: 'k:d/a1',
+      },
     ]);
   });
 
diff --git a/plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.ts b/plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.ts
index 31398a137e..19a6dbe566 100644
--- a/plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.ts
+++ b/plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.ts
@@ -96,6 +96,21 @@ export function useEntityRelationNodesAndEdges({
       const visitedNodes = new Set<string>();
       const nodeQueue = [...rootEntityRefs];
 
+      const hasEdge = (
+        fromRef: string,
+        toRef: string,
+        relation: [string, string?],
+      ): boolean => {
+        return edges.some(
+          edge =>
+            fromRef === edge.from &&
+            toRef === edge.to &&
+            edge.relations.some(
+              rel => rel[0] === relation[0] && rel[1] === relation[1],
+            ),
+        );
+      };
+
       while (nodeQueue.length > 0) {
         const entityRef = nodeQueue.pop()!;
         const entity = entities[entityRef];
@@ -122,20 +137,26 @@ export function useEntityRelationNodesAndEdges({
               return;
             }
 
-            if (!unidirectional || !visitedNodes.has(rel.targetRef)) {
-              if (mergeRelations) {
-                const pair = relationPairs.find(
-                  ([l, r]) => l === rel.type || r === rel.type,
-                ) ?? [rel.type];
-                const [left] = pair;
-
+            if (mergeRelations) {
+              const pair = relationPairs.find(
+                ([l, r]) => l === rel.type || r === rel.type,
+              ) ?? [rel.type];
+              const [left] = pair;
+              const from = left === rel.type ? entityRef : rel.targetRef;
+              const to = left === rel.type ? rel.targetRef : entityRef;
+              if (!unidirectional || !hasEdge(from, to, pair)) {
                 edges.push({
-                  from: left === rel.type ? entityRef : rel.targetRef,
-                  to: left === rel.type ? rel.targetRef : entityRef,
+                  from,
+                  to,
                   relations: pair,
                   label: 'visible',
                 });
-              } else {
+              }
+            } else {
+              if (
+                !unidirectional ||
+                !hasEdge(entityRef, rel.targetRef, [rel.type])
+              ) {
                 edges.push({
                   from: entityRef,
                   to: rel.targetRef,