fix(service-datasource): migrateCredential's drop-inline refusal names an empty stored credential as empty

The refusal blamed a missing sys_secret row or a changed encryption key
when the existing ref decrypted to ''. It now names the credential as
empty in the connect path's wording; the missing-row / changed-key
branch keeps its sentence. Same refused status, same outcome.

Claude-Session: https://claude.ai/code/session_01ADHkmP66rDL21VeBrVWovN
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.changeset/29069-migrate-credential-empty-refusal.md

@@ -0,0 +1,10 @@
+---
+'@objectstack/service-datasource': patch
+---
+
+fix(service-datasource): the credential migration's drop-inline refusal names an empty stored credential as empty
+
+Clause-②: no
+Metadata-protocol: none
+
+When a datasource already references a stored secret that decrypts to an empty value (a row sealed empty before the admin doors refused an empty `secret`), the credential migration still refuses to drop the inline copy, with the same `refused` status, but its reason now says the credential is empty, in the connect path's wording, instead of blaming a missing `sys_secret` row or a changed encryption key. A missing row or a decrypt failure keeps its sentence.

packages/services/service-datasource/src/__tests__/datasource-admin-service.test.ts

@@ -631,11 +631,41 @@ describe('migrateCredential (#8155)', () => {
     const result = await h.service.migrateCredential('warehouse');
 
     expect(result.status).toBe('refused');
-    expect(result.reason).toContain('could not be resolved');
+    expect(result.reason).toBe(
+      "Datasource 'warehouse' already references a stored secret, but it could not be resolved or "
+        + 'decrypted (a missing `sys_secret` row, or a changed encryption key). Removing the inline '
+        + 'credential would leave this datasource with no working credential at all.',
+    );
+    expect(result.remedy).toContain('replaces the unresolvable reference');
     // The inline copy is the only working credential left — it stays.
     expect(h.store.get('warehouse')!.config?.password).toBe('hunter2');
   });
 
+  it('refuses to drop the inline copy when the existing ref decrypts to an empty value, and says it is empty', async () => {
+    // A row sealed empty before the admin doors refused an empty `secret`
+    // resolves to ''. The outcome is the same refusal; the cause is named as
+    // an empty credential, in the connect path's wording, not blamed on a
+    // missing row or a changed key.
+    const h = makeHarness({
+      seed: [legacyRow({ external: { credentialsRef: 'sys_secret://sealed-empty' } })],
+      readBackOverride: async () => '',
+    });
+    const result = await h.service.migrateCredential('warehouse');
+
+    expect(result.status).toBe('refused');
+    expect(result.reason).toBe(
+      "Datasource 'warehouse' already references a stored secret, but credential "
+        + "'sys_secret://sealed-empty' is empty (its sys_secret row holds an empty value). Removing the "
+        + 'inline credential would leave this datasource with no working credential at all.',
+    );
+    expect(result.reason).not.toContain('could not be resolved');
+    expect(result.reason).not.toContain('encryption key');
+    expect(result.remedy).toContain("set the datasource's secret again");
+    // Same outcome as the missing-row branch: nothing written, inline copy kept.
+    expect(h.store.get('warehouse')!.config?.password).toBe('hunter2');
+    expect(h.ops).toEqual(['readSecret']);
+  });
+
   it('refuses when the host has no readable secret store', async () => {
     const h = makeHarness({ seed: [legacyRow()], noReadSecret: true });
     const result = await h.service.migrateCredential('warehouse');

packages/services/service-datasource/src/datasource-admin-service.ts

@@ -1176,7 +1176,22 @@ export class DatasourceAdminService implements IDatasourceAdminService {
       // inline copy is the last cleartext copy, so it is dropped only once the
       // existing ref is proved resolvable.
       const resolved = await this.tryReadSecret(plan.credentialsRef);
-      if (resolved == null || resolved === '') {
+      // [#29069] An empty credential is told apart from one that is gone, in
+      // the connect path's wording (`DatasourceConnectionService.connect`'s
+      // `secret === ''` branch): a row sealed empty before the admin doors
+      // refused an empty `secret` decrypts to ''. The outcome is the same
+      // refusal — dropping the inline copy would leave nothing that works.
+      if (resolved === '') {
+        return this.refuse(
+          name,
+          `Datasource '${name}' already references a stored secret, but credential `
+            + `'${plan.credentialsRef}' is empty (its sys_secret row holds an empty value). Removing the `
+            + 'inline credential would leave this datasource with no working credential at all.',
+          'Re-enter the credential in the connection form\'s secret field to set the datasource\'s '
+            + 'secret again — that rebinds it and replaces the empty one; the inline copy can then be removed.',
+        );
+      }
+      if (resolved == null) {
         return this.refuse(
           name,
           `Datasource '${name}' already references a stored secret, but it could not be resolved or `