The library-scan locks live in runtime.py, and the lock guard sees the or form (#749)

[chchatzop]

Fixes #749. Stacked on #903 - merge that first (both add at the top of the changelog's Unreleased).

What was wrong

#731 (#580) left two lock-like objects built at module level in dcc.py, a module !rehash reloads:

_library_scans = globals().get("_library_scans") or threading.BoundedSemaphore(MAX_CONCURRENT_LIBRARY_SCANS)
_lookup_misses_lock = globals().get("_lookup_misses_lock") or threading.Lock()

It worked - globals().get keeps the old object across a reload - but the rule (#235) is that a reloaded module never constructs its own lock: runtime.py, which nothing reloads, owns them and the module binds the name. And tests/test_no_reloaded_module_owns_a_lock.py could not see these two: it matched a factory call only as the whole right-hand side, and here the call sits inside a BoolOp.

What changed

• runtime.py: MAX_CONCURRENT_LIBRARY_SCANS, library_scans (the semaphore) and lookup_memory_lock, beside the other locks. dcc.py binds all three by name, like queue_lock.
• The memories themselves (_lookup_misses, _lookup_hits, _lookup_folders) stay in dcc.py. The issue left that open; runtime.py's containers are configuration state that test_runtime_state requires to be bound through defaults.py and reset between tests - moving these there failed nine of its checks, and they are dcc's own cache, not that.
• The guard: constructs_a_lock() walks the whole value, so a factory call inside or, a conditional or an argument is found. Its synthetic control gains globals().get(..) or threading.Lock(), the BoundedSemaphore form, a conditional, and a plain or {} that must not be flagged.
• Dev changelog only - no behaviour change.

Test

Run before the move, the extended guard names exactly the two (dcc.py:97 _library_scans, dcc.py:99 _lookup_misses_lock). TheLookupLocksAreBoundFromRuntime (2): both are runtime's objects, and the semaphore admits exactly MAX_CONCURRENT_LIBRARY_SCANS scans. Against the old code the guard and the identity check fail.

Verified

Full suite on the stacked branch: 6431 OK (19 skipped).

🤖 Generated with Claude Code

https://claude.ai/code/session_01AP6LSxkr4n9dMFNSNMogmW

[chchatzop]

Rebased onto main and retargeted to it: #903, which this was stacked on, was superseded by #909 (merged). The code is byte-for-byte the same commit; the changelog entry was re-inserted by hand at the top of Unreleased, above #909's - a plain rebase had spliced it into the middle of #909's entry without reporting a conflict. Full suite on the rebased branch: 6432 OK.