Thread safety#

Most functions and classes are thread safe. Notable exceptions are documented here.

Not thread safe	Comment
`enable_verbose_debug_messages()`	This function modifies global state.
`AbstractFetcher.fetch_all()`	When `selective_fetch_all=True` (default), a temporary `Mapper` instance may be used. All built-in fetchers (e.g. the `SqlFetcher`) inherit from this class.
`Fetcher.initialize_sources()`	Invoked implicitly before all translation tasks. Results are cached when using a `MultiFetcher` or `AbstractFetcher` subtype, after which `initialize_sources` is thread-safe for these types.
`Translator.translated_names()`	Reflects the most recent `Translator.translate()` call on the instance. The `translate` call itself is thread safe (when `copy=True`), but the recorded names are not. Use `Translator.map()` in multi-threaded contexts.
`Translator.go_offline()`	Performs `Fetcher` teardown. Once offline, the `Translator` is safe to share.

Transformers#

The Translator.transformers are reused for all translation tasks. Bundled Transformer types are thread safe. Transformers are inherited by any TranslationMap instances created by the Translator, including the Translator.cache) created by Translator.go_offline().

Fetchers#

Some thread-unsafe Fetcher operations emit a ConcurrentOperationWarning on a best-effort basis when entered from multiple threads at once. This detection is cheap and lock-free, so it may miss races; absence of a warning does not prove correctness.