Fix infinite loop in directory discovery

The `fix_storage` method enters an infinite loop when there are other
directories that have `root_path` as prefix.

For example, if the contents of the bucket look like this:
```
gs://mybucket/abc/file.txt
gs://mybucket/abc123/file.txt
```

this code results in an infinite loop:
```python
from fs import open_fs
open_fs("gs://mybucket/abc?strict=False").fix_storage()
```

In order to avoid this, we need to ensure `root_path` has a trailing
"/", when listing blobs, which prevents "abc123/file.txt" from being
listed as child of "abc".

Additionally, `Bucket.list_blobs` was deprecated in favor of
`Client.list_blobs` (see [reference documentation][1]).

[1]: https://cloud.google.com/python/docs/reference/storage/1.44.0/buckets#listblobsmaxresultsnone-pagetokennone-prefixnone-delimiternone-startoffsetnone-endoffsetnone-includetrailingdelimiternone-versionsnone-projectionnoacl-fieldsnone-clientnone-timeout60-retrygoogleapicoreretryretry-object

CHANGELOG.rst

@@ -18,6 +18,22 @@ Possible types of changes are:
 
 
 
+Unreleased
+----------
+Fixed
+'''''
+- Infinite loop in ``GCSFS.fix_storage()`` when the bucket contains blobs or
+  directories (with or without empty blob) on the same hierarchy level as
+  ``root_path`` and whose name also starts with the ``root_path`` directory
+  name. For example, having ``root_path = "gs://mybucket/abc"`` and these
+  blobs in the bucket:
+
+  .. code-block::
+
+      gs://mybucket/abc/file.txt
+      gs://mybucket/abc123/file.txt
+
+
 1.5.1 - 03.06.2022
 ------------------
 Fixed

fs_gcsfs/_gcsfs.py

@@ -481,7 +481,7 @@ def fix_storage(self) -> None:  # TODO test
         As GCS is no real file system but only a key-value store, there is also no concept of folders. S3FS and GCSFS overcome this limitation by adding
         empty files with the name "<path>/" every time a directory is created, see https://fs-gcsfs.readthedocs.io/en/latest/#limitations.
         """
-        names = [blob.name for blob in self.bucket.list_blobs(prefix=self.root_path)]
+        names = [blob.name for blob in self.client.list_blobs(self.bucket, prefix=forcedir(self.root_path))]
         marked_dirs = set()
         all_dirs = set()
 

fs_gcsfs/tests/test_gcsfs.py

@@ -117,15 +117,29 @@ def test_create_property_does_not_create_file_if_emptyish_root_path(root_path, c
 
 def test_fix_storage_adds_binary_blobs_with_empty_string_as_directory_marker(bucket, gcsfs):
     # Creating a 'nested' hierarchy of blobs without directory marker
+    content = b"Is this a test? It has to be. Otherwise I can't go on."
     for path in ["foo/test", "foo/bar/test", "foo/baz/test", "foo/bar/egg/test"]:
         key = gcsfs._path_to_key(path)
         blob = bucket.blob(key)
-        blob.upload_from_string(b"Is this a test? It has to be. Otherwise I can't go on.")
+        blob.upload_from_string(content)
+
+    # Create a blob inside a directory that is sibling to `root_path` and whose path happens to be the same as the
+    # `root_path`, but with an added suffix. That directory should be left untouched, as it is not contained under
+    # `root_path`, despite sharing the same path prefix.
+    sibling_dir = gcsfs.root_path.rstrip("/") + "_suffix"
+    file_in_sibling_dir = f"{sibling_dir}/test"
+    bucket.blob(file_in_sibling_dir).upload_from_string(content)
+
     gcsfs.fix_storage()
 
+    # Assert that empty blobs were created for directories in the hierarchy under `root_path`
     for path in ["", "foo", "foo/bar", "foo/baz", "foo/bar/egg"]:
         assert gcsfs.isdir(path)
 
+    # Assert that the sibling directory was left untouched
+    assert not bucket.blob(sibling_dir).exists()
+    assert bucket.blob(file_in_sibling_dir).exists()
+
 
 def test_fix_storage_does_not_overwrite_existing_directory_markers_with_custom_content(bucket, gcsfs):
     for path in ["foo/test"]: