TObjFlag.__repr__ raises on valid fBits, and several enum members mislabel class-specific bits as TObject bits

[nsmith-]

🤖 AI generated content

1. repr() of a successfully read object can raise. src/rootfilespec/bootstrap/TObject.py:53-63 raises ValueError: Invalid bits set in TObjFlag: 0x… for any bit not in the enum. The class's own docstring (:15-17) quotes the rule that makes this unsatisfiable: "Bits 14 - 23 can be used in different class hierarchies". Reproduced: repr(TObjFlag(0x200)) (TH1::kNoStats, i.e. any histogram after SetStats(0)), TObjFlag(0x800) (a TAxis bit) and TObjFlag(0x100) (TObject::kNoContextMenu, BIT(8), simply missing from the enum) all raise. The read succeeds; print() crashes.

2. Mislabelled members (TObject.py:41-50). These are class-specific bits that happened to show up on TStreamerInfo/TStreamerElement/TList objects, not TObject bits. Reviewers checked the pinned ROOT tree (TVirtualStreamerInfo.h:72-88, TStreamerElement.h:69-78, TObject.h:70-96):

Member	Value	Actually
kNotSure	0x10000	TStreamerInfo::kIsCompiled (BIT 16); TCollection::kUseRWLock
kMysteryStreamer	0x20000	TStreamerInfo::kBuildOldUsed (BIT 17)
kMysteryStreamer2	0x1000	TStreamerElement::kWrite / TStreamerInfo::kCannotOptimize / TClonesArray::kBypassStreamer (BIT 12)
kDoNotDelete	0x2000	TObject::kInvalidObject / TStreamerElement::kDoNotDelete / TStreamerInfo::kIgnoreTObjectStreamer (BIT 13)
kListOfRules	0x4000	TCollection::kIsOwner (BIT 14) — the listOfRules list has it because it is an owner, not because it holds rules

Three of these are load-bearing in the spec and tested nowhere in the code: kIgnoreTObjectStreamer on a TStreamerInfo (Streamer-driven reading §4.2, see #94), kHasRange = BIT(6) on a TStreamerElement (value 0x40, which the enum calls kCannotPick; needed by #41), and kBypassStreamer on a TClonesArray (Collections §12).

Suggested fix: make __repr__ total (print unknown bits as hex; drop the TODO on :52 about validating at construction — validation is impossible by design). Keep only genuine TObject bits (0–13 plus the private 24–27, adding kNoContextMenu = 0x100, kInvalidObject = 0x2000) in TObjFlag, and define per-class flag enums (TStreamerInfo, TStreamerElement, TCollection, TClonesArray) where the code needs them.

Severity / size: medium (exception from repr on ordinary histograms) / S.

Related: #41 (kHasRange), #94, #101, #110 (read fBits unsigned), #100.

Assisted-by: claude-code:claude-fable-5-1