The fifth convention: whether a call changes what it is called on

[matt-edmondson]

The four conventions say whether a call can fail, whether the callee may keep an argument, who frees what, and whether an argument is read-only. They say nothing about the receiver — so a schema could describe an interface whose every method might change the world, and a generator had no way to say otherwise.

The C++ target document's §3 writes find() as const, and #160's bridge could not emit it. A test asserted that gap rather than leaving it merely absent. This closes it.

SchemaFunction.IsQuery

{ "returnType": { "TypeName": "Optional", "elementType": { "TypeName": "Object", "className": "RigidBody" } }, "isQuery": true, "name": "Find" }

A query answers; a command acts.

Held per function rather than globally, unlike the other four. Those are rules the program keeps, which is what makes holding them globally the thing that stops annotation creep. This genuinely differs from one signature to the next, because it is a property of what the call does.

False by default and omitted from the file when it is, so every function a schema already declares goes on generating exactly as it did.

A query that answers nothing

A query returning Void changes nothing and answers nothing, so calling it cannot be observed at all.

Reported as a warning rather than an error: it is as often a signature someone is part way through writing as one they meant — the return type is usually the half that is missing. Result<Void> is exempt, because it answers whether the call succeeded, which is something.

The bridge

Schema.Cpp emits it as the trailing const, which is what lets a caller holding a const reference call it at all:

[[nodiscard]] virtual std::optional<RigidBody> find(EntityId entity) const = 0;

§3's acceptance test now asserts the document's text including that const, and AQueryCannotYetSayItLeavesTheReceiverUnchanged is replaced by AQuerySaysItLeavesTheReceiverUnchanged — which also checks a command does not claim it, since a rule that only ever says yes is not a rule. The suite records that the gap closed rather than quietly losing the note that it ever existed.

Format version

formatVersion moves to 6. Additive and omitted when false, but a version 5 reader would drop it and generate a signature that promises less than the schema does.

Testing

403 in Schema.Test (6 new in QueryFunctionTests), 46 in Schema.Cpp.Test, 201 in SchemaEditor.Test. Whole solution builds with 0 warnings.

🤖 Generated with Claude Code

https://claude.ai/code/session_01AhoPJ5AbxP8QEBNxPQYEPk

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Generated by Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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