Implement a new module-level merge_configs() function in
src/cleveractors/config_utils.py that exposes the §3.1 deep-merge
algorithm as a public, importable API.
Motivation: The internal ReactiveConfigParser._merge_configs() method
mutates its base dict in place and only accepts two dicts. The
CleverThis router (wave 2 of cleveragents/cleveragents-webapp#275)
needs a public merge_configs() to combine platform base configs with
actor configs from the database without side-effects.
Implementation:
- merge_configs(*dicts) accumulates into a fresh dict, applying each
overlay using the §3.1 rules:
* Key absent → add via deep copy.
* Both mappings → deep-merge recursively (_apply_merge helper).
* Both sequences → extend (existing + deep copy of new).
* Otherwise → replace with deep copy of new value.
- Runtime type guard: non-dict arguments raise TypeError immediately
(fail-fast per CONTRIBUTING.md argument validation guidelines).
- Zero-argument call returns {}.
- Inputs are never mutated (copy.deepcopy used for all stored values).
- Internal _merge_configs on ReactiveConfigParser is unchanged.
Exports: merge_configs added to cleveractors/__init__.py import and
__all__ so consumers can use 'from cleveractors import merge_configs'.
Tests:
- 15 Behave BDD scenarios in features/merge_configs.feature covering
zero-args, single-dict deep copy (including nested identity),
empty-dict arguments, TypeError on None, absent-key insertion,
scalar override, recursive mapping merge, sequence append,
three-dict chained merge, deep nesting, input mutation guard,
result-mutation independence from inputs, and type-mismatch
replacement.
- 4 Robot Framework integration tests in robot/config.robot with
strengthened assertions (len check, overlay immutability).
- 5 ASV benchmarks with realistically sized three-way merge fixtures
(50 keys each with overlap).
Project files: Added CONTRIBUTORS.md per CONTRIBUTING.md §PR Process
rule 8.
Coverage: 97% (config_utils.py: 100%).
Quality gates: ruff lint ✓, pyright strict ✓ (0 errors),
all BDD/Robot tests ✓.
ISSUES CLOSED: #11
hurui200320