CNA-BUG-273: CLAUDE.md and AGENTS.md tell contributors to throw std::runtime_error after disposal, while the public layer throws System::ObjectDisposedException at 51 sites in the graphics module alone

CNA snapshot c1c316b9  ·  Known Issues › Current bugs  ·  source links pinned to c1c316b9

CNA's contributor instruction files give one rule for a disposed object (throw std::runtime_error), while the graphics, audio, media and net modules throw System::ObjectDisposedException, XNA's exception for that case.

Identifier

CNA-BUG-273

Category

Bug

Subsystem

Documentation & release tooling

Status

Open

Verified against

CNA c1c316b9 (c1c316b9c7a846ce8002809c151fcd1af14942c9)

Severity

Low (a triage suggestion, not a project priority)

Evidence basis

Source-verified: read at TARGET, not executed

Tests touching this area

None

Affected contract

CLAUDE.md and AGENTS.md, the IDisposable section ("throw std::runtime_error if used after disposal")

Expected behaviour

The instruction files that contributors and coding agents follow describe the convention the code applies: XNA's ObjectDisposedException for use after disposal.

Actual behaviour at TARGET

CLAUDE.md and AGENTS.md say, at the end of the IDisposable section, “Always check isDisposed_ before acting; throw std::runtime_error if used after disposal.” At the snapshot the public XNA layer throws System::ObjectDisposedException for that case: 51 throw sites in modules/graphics/src, 21 in audio, 17 in net and 1 in media; the std::runtime_error throws in the graphics sources concern other conditions. occlusionquery-support.md calls throwing ObjectDisposedException the “project-wide resource rule”, and the SharpRuntime Extensions section of both instruction files lists System::Exception and its subclasses among the types that belong to sharp-runtime. A contributor or agent who follows the IDisposable sentence writes an exception that a catch clause for ObjectDisposedException, as XNA code has, does not catch (CNA-BUG-122 records one place that throws std::runtime_error for a disposed object, ContentManager::Load; Game::AssertNotDisposed in Game.cpp is another).

Source locations

• CLAUDE.md — IDisposable section: the runtime_error rule
• AGENTS.md — the same rule in the copy of the instructions
• modules/graphics/src/Xna/SpriteBatch.cpp — one of the 51 ObjectDisposedException sites in the graphics module

Evidence

Read at c1c316b9; nothing was executed. The counts are of throw statements naming ObjectDisposedException in each module's src directory (graphics has one further site that uses ObjectDisposedException::ThrowIf). The sentence appears verbatim in both files, but AGENTS.md is not kept as a copy of CLAUDE.md at this snapshot: the two files differ in 19 places, so the sentence has to be changed in each file.

Re-verified at c1c316b9: both instruction files still carry the sentence; the per-module counts of throw statements naming ObjectDisposedException were recounted with git grep (graphics 51, audio 21, net 17, media 1, identical at the b0e97bb1 snapshot and at c1c316b9). Not executed.

Focused reproduction

No focused reproduction is known. Nothing has been invented here; the evidence above is what exists.

Current tests

None: no test or check compares the instruction files with the code's exception conventions.

Regression test

State System::ObjectDisposedException in both files, which have to be edited separately.

Blast radius

Contributors and coding agents who apply the rule when adding code that touches a disposed object.

Workaround

Follow the code's convention (ObjectDisposedException), which the site's language-conventions Deep Dive states.