From 73d8dd2d9d4ebc235d8d78959acd9ccbde2cafcc Mon Sep 17 00:00:00 2001
From: Bonobo <github@in9.at>
Date: Wed, 2 Sep 2026 13:34:35 +0200
Subject: [PATCH] fix(neo4j): reconcile removed application artifacts

---
 src/build/neo4j/bolt.ts   | 23 +++++++++++++++++++++++
 src/build/neo4j/cypher.ts |  4 ++++
 test/artifacts.test.ts    |  9 ++++++++-
 test/neo4j-bolt.test.ts   | 24 ++++++++++++++++++++++++
 4 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/src/build/neo4j/bolt.ts b/src/build/neo4j/bolt.ts
index 2e1246b..3429580 100644
--- a/src/build/neo4j/bolt.ts
+++ b/src/build/neo4j/bolt.ts
@@ -18,6 +18,7 @@
  * (json) output entirely.
  */
 
+import type { ManagedTransaction } from "neo4j-driver";
 import type { Logger } from "../../utils";
 import type { EdgeRow, GraphRows, NodeRow, Prop } from "./rows";
 import { chunk } from "./rows";
@@ -130,6 +131,28 @@ export async function boltWriter(
         );
       }
     }
+    // Full runs reconcile the current application's artifact ownership. Artifact and ConfigKey
+    // ids are neutral across sibling analyzers, so remove only this app's stale ownership edges
+    // first and delete the shared subtree only when no Application still owns the artifact.
+    if (fullRun && appId !== null) {
+      const artifactIds = rows.nodes
+        .filter((n) => n.labels.includes("Artifact"))
+        .map((n) => n.value);
+      await withSession(session, async (s) => {
+        await s.executeWrite(async (tx: ManagedTransaction) => {
+          await tx.run(
+            `MATCH (a:Application {id: $appId})-[r:HAS_ARTIFACT]->(artifact:Artifact) ` +
+              `WHERE NOT artifact.id IN $artifactIds DELETE r`,
+            { appId, artifactIds },
+          );
+          await tx.run(
+            `MATCH (artifact:Artifact) WHERE NOT ()-[:HAS_ARTIFACT]->(artifact) ` +
+              `OPTIONAL MATCH (artifact)-[:DEFINES_CONFIG]->(config:ConfigKey) ` +
+              `DETACH DELETE config, artifact`,
+          );
+        });
+      });
+    }
 
     // 3. diff content_hash.
     const dbHash = new Map<string, string | null>();
diff --git a/src/build/neo4j/cypher.ts b/src/build/neo4j/cypher.ts
index 986d7b0..256ba3b 100644
--- a/src/build/neo4j/cypher.ts
+++ b/src/build/neo4j/cypher.ts
@@ -40,6 +40,10 @@ function wipe(appId: string): string {
     "OPTIONAL MATCH (a)-[:TS_HAS_MODULE]->(m:TSModule)",
     "OPTIONAL MATCH (m)-[:TS_DECLARES|TS_HAS_METHOD|TS_HAS_FIELD|TS_HAS_BODY_NODE*1..]->(x)",
     "DETACH DELETE x, m, a;",
+    "MATCH (artifact:Artifact)",
+    "WHERE NOT ()-[:HAS_ARTIFACT]->(artifact)",
+    "OPTIONAL MATCH (artifact)-[:DEFINES_CONFIG]->(config:ConfigKey)",
+    "DETACH DELETE config, artifact;",
   ].join("\n");
 }
 
diff --git a/test/artifacts.test.ts b/test/artifacts.test.ts
index b408624..ea7c4e8 100644
--- a/test/artifacts.test.ts
+++ b/test/artifacts.test.ts
@@ -10,7 +10,7 @@ import * as fs from "node:fs";
 import * as os from "node:os";
 import * as path from "node:path";
 import { analyze } from "../src/core";
-import { project } from "../src/build/neo4j";
+import { project, renderCypher } from "../src/build/neo4j";
 import type { AnalysisOptions } from "../src/options";
 
 const FIXTURE = path.resolve(import.meta.dir, "fixtures/artifacts-app");
@@ -246,4 +246,11 @@ describe("Neo4j projection — neutral :Artifact/:Package (#101)", () => {
       rows.edges.some((e) => e.type === "TS_UNRESOLVED_IMPORT" && String(e.to.value).endsWith("/@external/left-pad")),
     ).toBe(true);
   });
+
+  test("snapshot cleanup removes only unowned artifact subtrees", () => {
+    const cypher = renderCypher(rows, root.id);
+    expect(cypher).toContain("WHERE NOT ()-[:HAS_ARTIFACT]->(artifact)");
+    expect(cypher).toContain("OPTIONAL MATCH (artifact)-[:DEFINES_CONFIG]->(config:ConfigKey)");
+    expect(cypher).toContain("DETACH DELETE config, artifact");
+  });
 });
diff --git a/test/neo4j-bolt.test.ts b/test/neo4j-bolt.test.ts
index 9015a52..468dff9 100644
--- a/test/neo4j-bolt.test.ts
+++ b/test/neo4j-bolt.test.ts
@@ -163,6 +163,30 @@ containerSuite("neo4j bolt writer", () => {
     120_000,
   );
 
+  test(
+    "a full run prunes an artifact no longer owned by the application",
+    async () => {
+      const rows = project((await analyze(optsFor())).application);
+      const victim = rows.nodes.find((n) => n.labels.includes("Artifact"))?.value;
+      expect(victim).toBeDefined();
+
+      const reduced = {
+        nodes: rows.nodes.filter((n) => n.value !== victim),
+        edges: rows.edges.filter((e) => e.from.value !== victim && e.to.value !== victim),
+      };
+      await boltWriter(reduced, cfg, log, true);
+
+      expect(
+        await num(
+          "MATCH (:Application)-[:HAS_ARTIFACT]->(a:Artifact {id:$id}) RETURN count(a)",
+          { id: victim },
+        ),
+      ).toBe(0);
+      expect(await num("MATCH (a:Artifact {id:$id}) RETURN count(a)", { id: victim })).toBe(0);
+    },
+    120_000,
+  );
+
   test(
     "migrates a 1.1.0-shaped graph to the current schema, wiping legacy residue (#46)",
     async () => {