Normalize Etag format

CHANGELOG.md

@@ -11,6 +11,7 @@ Unreleased
 - Added `**kwargs` to `AzureBlobFileSystem.exists()`
 - Populate `AzureBlobFile.version_id` on write when `version_aware` is enabled.
 - Fixed issue where unawaitable Credential types were incorrectly awaited (#431)
+- Fixed bug where `fs.ls(detail=True)` returned Etag formatted without double quotes.[#544](https://github.com/fsspec/adlfs/pull/544)
 
 2026.2.0
 --------

adlfs/spec.py

@@ -897,6 +897,12 @@ async def _details(
                 for key in FORWARDED_BLOB_PROPERTIES
                 if content.has_key(key)  # NOQA
             }
+
+            # Normalize etag to always return a string with quotes for consistency
+            if data.get("etag") and data["etag"] is not None:
+                etagVal = data["etag"]
+                if not etagVal.startswith('"') and not etagVal.endswith('"'):
+                    data["etag"] = f'"{etagVal}"'
             if self.version_aware:
                 data.update(
                     (key, content[key])

adlfs/tests/test_spec.py

@@ -2571,3 +2571,28 @@ class TestCloseCredential:
     async def test_close_credential(self, credential):
         file_obj = SimpleNamespace(credential=credential)
         await close_credential(file_obj)
+
+
+def test_etag_normalized_form(storage):
+    """
+    Tests a consistent quoted etag format with ls() and info() calls.
+    """
+    fs = AzureBlobFileSystem(
+        account_name=storage.account_name,
+        connection_string=CONN_STR,
+    )
+    path = "data/root/a/file.txt"
+    # Get etag info from ls(detail = True) and info()
+    ls_results = fs.ls(path, detail=True, refresh=True)
+    ls_etag = [f["etag"] for f in ls_results if f["name"] == path][0]
+
+    info_etag = fs.info(path, refresh=True)["etag"]
+
+    assert info_etag == ls_etag
+
+    # Validate both etags are quoted
+    assert ls_etag.startswith('"') and info_etag.startswith('"')
+    assert ls_etag.endswith('"') and info_etag.endswith('"')
+
+    # Validate etag from info() is not double quoted
+    assert not info_etag.startswith('""') and not info_etag.endswith('""')