fix(orm): handle omitted needs dependencies for ext result fields

When a user omits a field that is a `needs` dependency of an active ext
result field, the computed field was silently missing from results.
Ensure needs dependencies are un-omitted for the DB query and stripped
from the final result, mirroring the existing `select` path behavior.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: genu

packages/orm/src/client/client-impl.ts

@@ -917,9 +917,17 @@ function prepareArgsForExtResult(
 
     if (omit && extResultDefs.size > 0) {
         const newOmit = { ...omit };
-        for (const fieldName of extResultDefs.keys()) {
+        for (const [fieldName, fieldDef] of extResultDefs) {
             if (newOmit[fieldName]) {
+                // strip ext result field names from omit (they don't exist in the DB)
                 delete newOmit[fieldName];
+            } else {
+                // this ext result field is active — ensure its needs are not omitted
+                for (const needField of Object.keys(fieldDef.needs)) {
+                    if (newOmit[needField]) {
+                        delete newOmit[needField];
+                    }
+                }
             }
         }
         result = { ...result, omit: newOmit };
@@ -1039,9 +1047,16 @@ function applyExtResultToRow(
     }
 
     if (omit && extResultDefs.size > 0) {
-        for (const fieldName of extResultDefs.keys()) {
+        for (const [fieldName, fieldDef] of extResultDefs) {
             if (omit[fieldName]) {
                 omittedExtResultFields!.add(fieldName);
+            } else {
+                // this ext result field is active — track needs that were originally omitted
+                for (const needField of Object.keys(fieldDef.needs)) {
+                    if (omit[needField]) {
+                        injectedNeedsFields.add(needField);
+                    }
+                }
             }
         }
     }

tests/e2e/orm/plugin-infra/ext-result.test.ts

@@ -280,6 +280,31 @@ describe('Plugin extended result fields', () => {
         expect((users[0] as any).upperName).toBeUndefined();
     });
 
+    it('should still compute virtual fields when their needs dependency is omitted', async () => {
+        const extDb = db.$use(
+            definePlugin({
+                id: 'greeting',
+                result: {
+                    User: {
+                        upperName: {
+                            needs: { name: true },
+                            compute: (user) => user.name.toUpperCase(),
+                        },
+                    },
+                },
+            }),
+        );
+
+        await extDb.user.create({ data: { name: 'Alice' } });
+
+        // omit the `name` field which is a `needs` dependency of `upperName`
+        const users = await extDb.user.findMany({ omit: { name: true } });
+        // upperName should still be computed even though its needs dep was omitted
+        expect(users[0]!.upperName).toBe('ALICE');
+        // the omitted `name` field should not appear in the result
+        expect((users[0] as any).name).toBeUndefined();
+    });
+
     it('should compose virtual fields from multiple plugins', async () => {
         const plugin1 = definePlugin({
             id: 'plugin1',