## backends.HistoryEntry


One native commit / snapshot / version, as listed by [ObjectBackend.history](testing.ObjectBackend.md#tether.testing.ObjectBackend.history).


Usage

``` python
backends.HistoryEntry(
    id,
    when=None,
    message="",
    refs=list(),
)
```


[id](backends.HistoryEntry.md#tether.backends.HistoryEntry.id) is what the backend accepts as the locator's `at` field, so a user can pick an entry and register (or re-base) an object at exactly that state.


## Parameter Attributes


`id: str`  
Native identifier: snapshot id, version, commit hash, …

`when: str | None = None`  
ISO-8601 timestamp (UTC) when known.

`message: str = ``""`  
Commit message or a synthesized description of the change.

`refs: list[str] = list()`  
Native branch/tag names pointing here (tether pins appear as `tether.<id>`).