From 9c7a7478242cdffd88afbf38b666a401c7007d7b Mon Sep 17 00:00:00 2001
From: Maximiliano Osorio <maxiosorio@gmail.com>
Date: Thu, 7 May 2026 21:41:22 -0400
Subject: [PATCH] fix(request): use update_columns:[] on nested target
 on_conflict

POST /modelconfigurations|/modelconfigurationsetups|/datasetspecifications
with relation fields (hasInput/hasOutput/hasModelCategory/hasPresentation)
returned 400 'null value in column "label"' when the client linked an
existing target by id alone.

buildJunctionInserts emitted update_columns:['label'] on the nested
target-entity insert. With nestedData = {id} only, on Hasura PK conflict
the existing target row got UPDATE label=NULL and tripped the not-null
constraint. Outer junction insert already used update_columns:[]; the
inner inconsistency was the bug.

Switch to update_columns:[] for link-or-noop semantics on existing target
rows. New target rows still insert with all supplied fields. Renames
remain the responsibility of the target's own PUT endpoint.

Tests: updated existing assertion in request.test.ts (Test 1) and added
two regressions covering hasInput as bare-string id and {id}-only object.
---
 src/mappers/__tests__/request.test.ts | 37 ++++++++++++++++++++++++++-
 src/mappers/request.ts                |  2 +-
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/mappers/__tests__/request.test.ts b/src/mappers/__tests__/request.test.ts
index c534046..a0c7b81 100644
--- a/src/mappers/__tests__/request.test.ts
+++ b/src/mappers/__tests__/request.test.ts
@@ -233,7 +233,11 @@ describe('buildJunctionInserts', () => {
     expect(targetData['id']).toBe('https://w3id.org/okn/i/mint/Economy');
     const targetConflict = category['on_conflict'] as Record<string, unknown>;
     expect(targetConflict['constraint']).toBe('modelcatalog_model_category_pkey');
-    expect(targetConflict['update_columns']).toEqual(['label']);
+    // Link-or-noop semantics: never overwrite columns on existing target rows.
+    // Previous value ['label'] caused null-label cascade (bug-087) when client
+    // sent only `{id}` -- nestedData lacked label and on_conflict overwrote
+    // the existing row's label with NULL.
+    expect(targetConflict['update_columns']).toEqual([]);
   });
 
   it('Test 2: generates UUID-based ID with https prefix when no ID provided', () => {
@@ -343,6 +347,37 @@ describe('buildJunctionInserts', () => {
     expect(nestedData).not.toHaveProperty('is_optional');
   });
 
+  it('Regression bug-087: linking by string id alone never sets update_columns to overwrite target.label with NULL', () => {
+    const configConfig = getResourceConfig('modelconfigurations')!;
+    const body = { hasInput: ['https://w3id.org/okn/i/mint/existing-ds-id'] };
+    const result = buildJunctionInserts(body, configConfig);
+    const inputs = result['inputs'] as Record<string, unknown>;
+    const data = inputs['data'] as Record<string, unknown>[];
+    const junctionRow = data[0] as Record<string, unknown>;
+    const nestedTarget = junctionRow['input'] as Record<string, unknown>;
+    const nestedData = nestedTarget['data'] as Record<string, unknown>;
+    // Client sent only an id -- nested data must contain only id, no label.
+    expect(Object.keys(nestedData)).toEqual(['id']);
+    expect(nestedData['id']).toBe('https://w3id.org/okn/i/mint/existing-ds-id');
+    // Critical: on_conflict must NOT update label. Updating label with the
+    // missing-from-payload value would null-clobber the existing target row
+    // and trip the not-null constraint on dataset_specification.label.
+    const targetConflict = nestedTarget['on_conflict'] as Record<string, unknown>;
+    expect(targetConflict['update_columns']).toEqual([]);
+  });
+
+  it('Regression bug-087: object-form link with only id likewise produces empty update_columns', () => {
+    const configConfig = getResourceConfig('modelconfigurations')!;
+    const body = { hasInput: [{ id: 'https://w3id.org/okn/i/mint/existing-ds-id' }] };
+    const result = buildJunctionInserts(body, configConfig);
+    const inputs = result['inputs'] as Record<string, unknown>;
+    const data = inputs['data'] as Record<string, unknown>[];
+    const junctionRow = data[0] as Record<string, unknown>;
+    const nestedTarget = junctionRow['input'] as Record<string, unknown>;
+    const targetConflict = nestedTarget['on_conflict'] as Record<string, unknown>;
+    expect(targetConflict['update_columns']).toEqual([]);
+  });
+
   it('Test 11: omits is_optional from junction row when isOptional is absent in request body (D-22)', () => {
     const configConfig = getResourceConfig('modelconfigurations')!;
     const body = {
diff --git a/src/mappers/request.ts b/src/mappers/request.ts
index 3e3200d..55ea21f 100644
--- a/src/mappers/request.ts
+++ b/src/mappers/request.ts
@@ -224,7 +224,7 @@ export function buildJunctionInserts(
             data: nestedData,
             on_conflict: {
               constraint: `${targetTable}_pkey`,
-              update_columns: ['label'],
+              update_columns: [],
             },
           },
         };