Cache generated builders

Builder caching and these controls are added in yidl-undoable==0.1.2. They are not available in version 0.1.1. This is generated-code caching, not storage of undo history.

Undoable normally persists compiled model-builder code using YIDL Cache. A hit skips YIDL/Astichi assembly and compilation for that model shape, then creates a fresh class and binds its current schema, defaults and callbacks. It does not cache live instances, history, callback results, or generated class identity.

Controls

Set these before the first import of yidl_undoable:

Environment variable	Behavior
YIDL_UNDOABLE_CACHE=off	Disable compiled-builder reuse
YIDL_UNDOABLE_CACHE=on or unset	Enable optional reuse
YIDL_UNDOABLE_CACHE_DIR=directory	Use that root instead of default locations; off wins

The default tries a source-adjacent __pycache__/yidl_cache location, then a per-user .yidl/cache location. The explicit root is namespace-separated. These are executable code artifacts: use a directory you control, not shared untrusted storage. Unsupported identity or unavailable/untrusted storage safely falls back to generation. Settings are fixed at import; restart after changing them or generator dependencies. Caching does not add manager thread/task isolation.

Inspect and clear

from yidl_undoable.code_cache import (
    cache_configuration, cache_statistics, cache_diagnostics, clear_code_cache,
)

configuration = cache_configuration()
statistics = cache_statistics()  # None when disabled.
diagnostics = cache_diagnostics()  # Recent completed requests, no automatic logging.

clear_code_cache() explicitly clears cache locations tracked by this process; it is not a scan of every user's cache directory. Generated source remains available as Model.__undoable_source__ on both misses and hits.

Field-specific accessors reduce dispatch on ordinary fields, constants and ready lazy values; managed reads still perform history selection. Caching addresses class generation, not commit cost or the history algorithm. The accessor experiment and bounded cache probe record their own workloads; their timings are not a general performance guarantee.