From a175c52de9afb0c2ff9cde6d3386ea7148032ff2 Mon Sep 17 00:00:00 2001
From: Patrice Bender <patrice.bender@sap.com>
Date: Wed, 12 Feb 2025 20:39:27 +0100
Subject: [PATCH] no need to add `is null` check for unmanaged

---
 db-service/lib/assert-constraint.js               | 11 ++++++-----
 test/bookshop/db/schema.cds                       |  3 ++-
 test/scenarios/bookshop/assert-constraint.test.js | 12 +++++++++++-
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/db-service/lib/assert-constraint.js b/db-service/lib/assert-constraint.js
index 1cadb59a0..ca8670d1e 100644
--- a/db-service/lib/assert-constraint.js
+++ b/db-service/lib/assert-constraint.js
@@ -61,11 +61,8 @@ function attachConstraints(_results, req) {
       const { condition, element } = constraint
       const xpr = []
       // if the element is nullable, we prepend xpr with `<element> IS NULL OR …`
-      if (!element.notNull) {
-        if (element.on)
-          // null check the whole xpr for unmanaged assocs which vanish in the result
-          xpr.unshift({ xpr: condition.xpr }, 'is', 'null', 'or')
-        else xpr.unshift({ ref: [element.name] }, 'is', 'null', 'or')
+      if (!element.notNull && !element.on) {
+        xpr.unshift({ ref: [element.name] }, 'is', 'null', 'or')
       }
       xpr.push({ xpr: condition.xpr })
       return {
@@ -138,6 +135,10 @@ function attachConstraints(_results, req) {
       return elmConstraints
     }
   }
+
+  function wrapInCaseWhen(xpr) {
+    return ['case', 'when', { xpr }, 'then', { val: true }, 'else', { val: false }, 'end']
+  }
 }
 
 async function checkConstraints(req) {
diff --git a/test/bookshop/db/schema.cds b/test/bookshop/db/schema.cds
index ecfe90184..2f7922e69 100644
--- a/test/bookshop/db/schema.cds
+++ b/test/bookshop/db/schema.cds
@@ -60,7 +60,8 @@ entity Genres : sap.common.CodeList {
       @assert.constraint: ( children.name in (
         'Fiction', 'Drama', 'Poetry', 'Fantasy', 'Science Fiction',
         'Romance', 'Mystery', 'Thriller', 'Dystopia', 'Fairy Tale',
-        'Non-Fiction', 'Biography', 'Autobiography', 'Essay', 'Speech'
+        'Non-Fiction', 'Biography', 'Autobiography', 'Essay', 'Speech',
+        'New Genre', 'New Sub-Genre'
        ) )
       children : Composition of many Genres
                    on children.parent = $self;
diff --git a/test/scenarios/bookshop/assert-constraint.test.js b/test/scenarios/bookshop/assert-constraint.test.js
index 7b77b2c5a..7948dc873 100644
--- a/test/scenarios/bookshop/assert-constraint.test.js
+++ b/test/scenarios/bookshop/assert-constraint.test.js
@@ -102,9 +102,19 @@ describe('Bookshop - assertions', () => {
           ]
         }, { auth: { username: 'alice' } })
       ).to.be.rejectedWith(/@assert.constraint ”children” failed/)
-      // nothing should have been created
       const genre = await SELECT.from(Genres).where('ID in (90, 91)')
       expect(genre).to.be.empty
+      // positive case
+      await POST('admin/Genres', {
+        ID: 100,
+        name: 'New Genre', // OK
+        children: [
+          { ID: 101, name: 'New Sub-Genre' }, // also OK
+        ],
+      }, { auth: { username: 'alice' } })
+      const genres = await SELECT.from(Genres).where('ID in (100, 101)')
+      // both should have been created
+      expect(genres).to.have.length(2)
     })
   })
 })