fix(client): preserve canonical format options in get_products

[bokelley]

Bug

ADCPClient.get_products() in v7.0.0-rc drops valid canonical format_options and can return an empty product list with FORMAT_PROJECTION_FAILED diagnostics.

Reproduction

Return a valid canonical product from an adapter:

TaskResult(
    status=TaskStatus.COMPLETED,
    success=True,
    data={
        "products": [{
            "product_id": "p1",
            "name": "Product 1",
            "description": "A test product",
            "publisher_properties": [
                {"selection_type": "all", "publisher_domain": "pub.example.com"}
            ],
            "format_options": [{
                "format_option_id": "p1-display",
                "format_kind": "image",
                "params": {"width": 300, "height": 250},
            }],
            "delivery_type": "non_guaranteed",
            "pricing_options": [{
                "pricing_model": "cpm",
                "pricing_option_id": "po1",
                "currency": "USD",
            }],
            "reporting_capabilities": {
                "available_reporting_frequencies": ["daily"],
                "expected_delay_minutes": 0,
                "timezone": "UTC",
                "supports_webhooks": False,
                "available_metrics": ["impressions"],
                "date_range_support": "date_range",
            },
        }]
    },
)

Calling the primary get_products() method produces no usable canonical product. Direct GetProductsResponse.model_validate() of the response succeeds.

Root cause

_canonicalize_get_products_result() first parses every response as LegacyGetProductsResponse. The generated legacy ProductFormatDeclaration does not declare canonical format_kind or params, so Pydantic discards them before project_legacy_product() runs. The projector consequently receives entries such as:

{"format_option_id": "p1-display", "canonical_formats_only": false, "experimental": false}

instead of the canonical declaration sent on the wire.

Expected behavior

The primary canonical client should parse a valid canonical GetProductsResponse without passing it through a lossy legacy model. Legacy-only responses should continue through the existing projection path.

Impact

Canonical-only sellers can return a valid wire response while Python v7.0.0-rc buyers silently lose those products. Raw MCP consumers are unaffected; the regression is in the high-level Python client canonicalization path.

[bokelley]

Triage

Classification: Bug
Bucket(s): client (label not in repo; gap noted in run summary)
Status: ready-to-implement

What the experts said:

• code-reviewer: Root cause confirmed — LegacyProductFormatDeclaration carries extra='ignore' so Pydantic silently drops format_kind/params before projection; the canonical fast-path must also call _remember_canonical_product_routes() and set metadata["projection"] = {"diagnostics": []} for shape consistency; regression test required
• dx-expert: Silent result.success=True with empty products is a foot-gun; fix direction (canonical-first, legacy fallback) matches the existing dialect-branching pattern already used in list_creatives() and get_media_buys() — and the _creative_dialect() return value at line 1717 is currently discarded rather than branched on, which is the missing wire-up

My take: Clear v7 regression — _canonicalize_get_products_result() unconditionally routes every wire response through the lossy legacy model, stripping canonical fields before project_legacy_product() runs. The fix is non-breaking and scoped to one method: canonical responses currently fail silently with empty products, so making them work is purely additive.

Implementation brief:

• In _canonicalize_get_products_result() (src/adcp/client.py:1503): parse raw_result as GetProductsResponse first; on success, call self._remember_canonical_product_routes(list(canonical.products)) and set metadata["projection"] = {"diagnostics": []} before returning
• On ValidationError, fall through to the existing LegacyGetProductsResponse projection path unchanged — legacy sellers are unaffected
• The async polling callsite at client.py:4854 delegates to _canonicalize_get_products_result() directly, so no separate change is needed there; note this in the PR body
• Add a regression test asserting format_kind and params survive round-trip through _canonicalize_get_products_result() with a canonical wire shape; run pytest -m 'not integration', mypy src/, ruff check ., black --check .

---

Triaged by Claude Code. Session: https://claude.ai/code/cse_01AtbrCX2K24YhUf8pR5Mfmi

---

Generated by Claude Code