From ad21da8740ddb02e7492bee366a938f5d58a5fa7 Mon Sep 17 00:00:00 2001
From: Fiddle-Config Team <fiddle-config-team@google.com>
Date: Tue, 21 Jul 2026 14:12:43 -0700
Subject: [PATCH] Allow empty string keys in daglish path parsing

PiperOrigin-RevId: 951692329
---
 fiddle/_src/daglish_extensions.py      | 2 +-
 fiddle/_src/daglish_extensions_test.py | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/fiddle/_src/daglish_extensions.py b/fiddle/_src/daglish_extensions.py
index 4f37ab4e..b0362de1 100644
--- a/fiddle/_src/daglish_extensions.py
+++ b/fiddle/_src/daglish_extensions.py
@@ -122,7 +122,7 @@ def is_unshareable(value: Any) -> bool:
         "|".join([
             r"\.(?P<attr_name>[\w_]+)",
             # future improvement: support escape sequences.
-            r"\[(?P<key>-?\d+|'[^']+'|\"[^\"]+\")\]",
+            r"\[(?P<key>-?\d+|'[^']*'|\"[^\"]*\")\]",
         ])
     )
 )
diff --git a/fiddle/_src/daglish_extensions_test.py b/fiddle/_src/daglish_extensions_test.py
index 8ac5a1c1..32509f16 100644
--- a/fiddle/_src/daglish_extensions_test.py
+++ b/fiddle/_src/daglish_extensions_test.py
@@ -102,6 +102,14 @@ def fn(x: int) -> int:
               daglish.Attr("foo"),
           ),
       },
+      {
+          "path": "['']",
+          "expected": (daglish.Key(""),),
+      },
+      {
+          "path": '[""]',
+          "expected": (daglish.Key(""),),
+      },
   )
   def test_parse_path(self, path, expected):
     actual = daglish_extensions.parse_path(path)