storage/inmemory: fix Patch() error handling (#4839)

storage/inmemory: fix Patch() error handling (#4838)

The Patch() method was intended to skip any records that do not
currently exist. However, currently inmemory.Backend.Patch() will return
ErrNotFound if the last record in the records slice is not found (it
will ignore any other previous records that are not found).

Update the error handling logic here to be consistent with the postgres
backend, and add a unit test to exercise this case.

Co-authored-by: Kenneth Jenkins <51246568+kenjenkins@users.noreply.github.com>

pkg/storage/inmemory/backend.go

@@ -269,12 +269,12 @@ func (backend *Backend) Patch(
 			// Skip any record that does not currently exist.
 			continue
 		} else if err != nil {
-			return
+			return serverVersion, patchedRecords, err
 		}
 		patchedRecords = append(patchedRecords, record)
 	}
 
-	return
+	return serverVersion, patchedRecords, nil
 }
 
 // patch updates the specified fields of an existing record, assuming the RWMutex is held.

pkg/storage/storagetest/storagetest.go

@@ -34,6 +34,17 @@ func TestBackendPatch(t *testing.T, ctx context.Context, backend storage.Backend
 		}
 	}
 
+	t.Run("not found", func(t *testing.T) {
+		mask, err := fieldmaskpb.New(&session.Session{}, "oauth_token")
+		require.NoError(t, err)
+
+		s := &session.Session{Id: "session-id-that-does-not-exist"}
+
+		_, updated, err := backend.Patch(ctx, []*databroker.Record{mkRecord(s)}, mask)
+		require.NoError(t, err)
+		assert.Empty(t, updated)
+	})
+
 	t.Run("basic", func(t *testing.T) {
 		// Populate an initial set of session records.
 		s1 := &session.Session{