capture version_id after upload

CHANGELOG.md

@@ -3,6 +3,7 @@
 Unreleased
 ----------
 - Added `**kwargs` to `AzureBlobFileSystem.exists()`
+- Populate `AzureBlobFile.version_id` on write when `version_aware` is enabled.
 
 2026.2.0
 --------

adlfs/spec.py

@@ -1995,9 +1995,10 @@ def __init__(
             by `cache_type`.
 
         version_id : str
-            Optional version to read the file at.  If not specified this will
-            default to the current version of the object.  This is only used for
-            reading.
+            Optional version of the blob.  For reads, specifies which version to
+            read; if not given, defaults to the current version.  On write, this
+            attribute is populated with the version created by the upload when the
+            filesystem has ``version_aware=True``.
 
         kwargs: dict
             Passed to AbstractBufferedFile
@@ -2264,9 +2265,11 @@ async def _async_upload_chunk(self, final: bool = False, **kwargs):
                     async with self.container_client.get_blob_client(
                         blob=self.blob
                     ) as bc:
-                        await bc.commit_block_list(
+                        response = await bc.commit_block_list(
                             block_list=block_list, metadata=self.metadata, **commit_kw
                         )
+                        if self.fs.version_aware:
+                            self.version_id = response.get("version_id")
             except ResourceExistsError as e:
                 raise FileExistsError(self.path) from e
             except Exception as e:
@@ -2278,23 +2281,27 @@ async def _async_upload_chunk(self, final: bool = False, **kwargs):
                     async with self.container_client.get_blob_client(
                         blob=self.blob
                     ) as bc:
-                        await bc.upload_blob(
+                        response = await bc.upload_blob(
                             data=data,
                             metadata=self.metadata,
                             overwrite=(self.mode == "wb"),
                         )
+                        if self.fs.version_aware:
+                            self.version_id = response.get("version_id")
                 elif length == 0 and final:
                     # just finalize
                     block_list = [BlobBlock(_id) for _id in self._block_list]
                     async with self.container_client.get_blob_client(
                         blob=self.blob
                     ) as bc:
                         try:
-                            await bc.commit_block_list(
+                            response = await bc.commit_block_list(
                                 block_list=block_list,
                                 metadata=self.metadata,
                                 **commit_kw,
                             )
+                            if self.fs.version_aware:
+                                self.version_id = response.get("version_id")
                         except ResourceExistsError:
                             raise FileExistsError(self.path)
                 else:

adlfs/tests/test_spec.py

@@ -2144,6 +2144,52 @@ def test_uses_block_size_for_partitioned_uploads(storage, mocker):
     assert len(mock_commit_block_list.call_args.kwargs["block_list"]) == expected_blocks
 
 
+def test_write_populates_version_id_when_version_aware(storage, mocker):
+    from azure.storage.blob.aio import BlobClient
+
+    fs = AzureBlobFileSystem(
+        account_name=storage.account_name,
+        connection_string=CONN_STR,
+        version_aware=True,
+        skip_instance_cache=True,
+    )
+
+    mock_commit_block_list = mocker.patch.object(
+        BlobClient,
+        "commit_block_list",
+        return_value={"version_id": "test-version-id"},
+    )
+
+    with fs.open("data/version-aware-write.bin", "wb") as f:
+        f.write(b"hello world")
+
+    assert mock_commit_block_list.called
+    assert f.version_id == "test-version-id"
+
+
+def test_write_does_not_populate_version_id_when_not_version_aware(storage, mocker):
+    from azure.storage.blob.aio import BlobClient
+
+    fs = AzureBlobFileSystem(
+        account_name=storage.account_name,
+        connection_string=CONN_STR,
+        version_aware=False,
+        skip_instance_cache=True,
+    )
+
+    mock_commit_block_list = mocker.patch.object(
+        BlobClient,
+        "commit_block_list",
+        return_value={"version_id": "test-version-id"},
+    )
+
+    with fs.open("data/not-version-aware-wb.bin", "wb") as f:
+        f.write(b"hello world")
+
+    assert mock_commit_block_list.called
+    assert f.version_id is None
+
+
 @pytest.mark.parametrize(
     "filesystem_blocksize, file_blocksize, expected_blocksize, expected_filesystem_blocksize",
     [