feat(cbr): USD и CNY тянутся всегда, новая валюта — с начала леджера

Валюта, впервые появившаяся в ZenMoney между двумя запусками, раньше показывала «нет курса» до следующего синка. Для валюты без сохранённых курсов история берётся с начала леджера, а не от общего курсора.

backend/src/fintracker/sources/cbr/sync.py

@@ -1,8 +1,14 @@
 """The `cbr` source: official RUB rates for every currency the ledger actually uses.
 
-What to fetch is derived from the data, not configured: the distinct currencies of
-`account.currency`, `cash_txn.income_currency` and `cash_txn.outcome_currency` (RUB itself
-is quoted as 1.0 by `pricing/fx.py`, so it is never requested).
+What to fetch: `ALWAYS_QUOTED` (the dollar and the yuan) whatever the data says, plus every
+currency the data uses — the distinct currencies of `account.currency`, `cash_txn.income_currency`
+and `cash_txn.outcome_currency`. RUB itself is quoted as 1.0 by `pricing/fx.py`, so it is never
+requested. The always-quoted pair exists because a currency that first appears in ZenMoney
+between two runs would otherwise show «нет курса» until the next run picked it up.
+
+A currency with no stored rates yet is fetched from the start of the ledger, not from the shared
+cursor: the cursor only knows what the OTHER currencies already have, and a new one needs the rates
+for every past transaction it appears in.
 
 Date range: from the earliest transaction minus 7 days (or today − 30 days when there are
 no transactions yet) up to today — `analytics.today_local()`, the deployment timezone, the
@@ -41,6 +47,8 @@ CURSOR_OVERLAP_DAYS = 3
 BACKFILL_TOLERANCE_DAYS = 14
 """How far the first stored quote may legitimately sit after the wanted start (holidays)."""
 NO_HISTORY_DAYS = 30
+ALWAYS_QUOTED = ("USD", "CNY")
+"""Fetched every run, in use or not: the two foreign currencies the ledger meets first."""
 CHUNK = 500
 
 
@@ -50,16 +58,9 @@ class CbrSource:
     async def sync(self, ctx: SyncContext) -> SyncResult:
         session = ctx.session
         today = today_local()
-        currencies = await currencies_in_use(session)
-        if not currencies:
-            log.info("cbr: only %s in use, nothing to fetch", BASE)
-            return SyncResult(
-                cursor_after=today.isoformat(),
-                counts={"currencies": 0, "rates": 0},
-                changed=False,
-            )
-
-        start = await _start_date(session, ctx.cursor_before, today)
+        currencies = sorted(set(await currencies_in_use(session)) | set(ALWAYS_QUOTED))
+        full_start = await _full_start(session, today)
+        start = await _start_date(session, ctx.cursor_before, today, full_start)
         warnings: list[str] = []
         stored = 0
         async with CbrClient() as client:
@@ -70,7 +71,11 @@ class CbrSource:
                 if not cbr_id:
                     warnings.append(f"{ccy} is not quoted by CBR — skipped (crypto or metal?)")
                     continue
-                quotes = await client.quotes(cbr_id, start, today)
+                # a currency the table has never seen needs the whole history, cursor or not
+                have = await session.scalar(
+                    select(RawCbrRate.ccy).where(RawCbrRate.ccy == ccy).limit(1)
+                )
+                quotes = await client.quotes(cbr_id, start if have else full_start, today)
                 stored += await _store(session, ccy, quotes)
                 fetched_currencies += 1
 
@@ -104,13 +109,19 @@ async def currencies_in_use(session: AsyncSession) -> list[str]:
     return sorted(code for code in found if code != BASE)
 
 
-async def _start_date(session: AsyncSession, cursor: str | None, today: date) -> date:
+async def _full_start(session: AsyncSession, today: date) -> date:
+    """Where the full history begins: a week before the first transaction, else 30 days back."""
     first_txn, _ = await ledger_date_range(session)
-    full_start = (
+    return (
         first_txn - timedelta(days=LOOKBACK_DAYS)
         if first_txn is not None
         else today - timedelta(days=NO_HISTORY_DAYS)
     )
+
+
+async def _start_date(
+    session: AsyncSession, cursor: str | None, today: date, full_start: date
+) -> date:
     cursor_date = _parse_date(cursor)
     if cursor_date is None:
         return full_start

backend/tests/fixtures/cbr/daily.xml

@@ -24,4 +24,12 @@
 <Value>101,4567</Value>
 <VunitRate>101,4567</VunitRate>
 </Valute>
+<Valute ID="R01375">
+<NumCode>156</NumCode>
+<CharCode>CNY</CharCode>
+<Nominal>1</Nominal>
+<Name>Êèòàéñêèé þàíü</Name>
+<Value>12,7654</Value>
+<VunitRate>12,7654</VunitRate>
+</Valute>
 </ValCurs>

backend/tests/fixtures/cbr/dynamic_cny.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="windows-1251"?>
+<ValCurs ID="R01375" DateRange1="01.09.2026" DateRange2="03.09.2026" name="Foreign Currency Market Dynamic">
+<Record Date="01.09.2026" Id="R01375">
+<Nominal>1</Nominal>
+<Value>12,7000</Value>
+<VunitRate>12,7</VunitRate>
+</Record>
+<Record Date="02.09.2026" Id="R01375">
+<Nominal>1</Nominal>
+<Value>12,7300</Value>
+<VunitRate>12,73</VunitRate>
+</Record>
+<Record Date="03.09.2026" Id="R01375">
+<Nominal>1</Nominal>
+<Value>12,7654</Value>
+<VunitRate>12,7654</VunitRate>
+</Record>
+</ValCurs>

backend/tests/sources/test_cbr.py

@@ -19,6 +19,7 @@ from fintracker.sources.cbr.sync import CbrSource
 
 USD_ID = "R01235"
 JPY_ID = "R01820"
+CNY_ID = "R01375"
 
 
 def settings() -> Settings:
@@ -39,7 +40,11 @@ def mock_cbr(mock_http, fixture_bytes, *, dynamic: dict[str, str] | None = None)
     daily = mock_http.get(DAILY_URL).mock(
         return_value=httpx.Response(200, content=fixture_bytes("cbr", "daily.xml"))
     )
-    files = dynamic or {USD_ID: "dynamic_usd.xml", JPY_ID: "dynamic_jpy.xml"}
+    files = dynamic or {
+        USD_ID: "dynamic_usd.xml",
+        JPY_ID: "dynamic_jpy.xml",
+        CNY_ID: "dynamic_cny.xml",
+    }
 
     def _dynamic(request: httpx.Request) -> httpx.Response:
         cbr_id = request.url.params.get("VAL_NM_RQ", "")
@@ -51,17 +56,19 @@ def mock_cbr(mock_http, fixture_bytes, *, dynamic: dict[str, str] | None = None)
     return daily, mock_http.get(DYNAMIC_URL).mock(side_effect=_dynamic)
 
 
-async def test_only_currencies_in_use_are_requested(app, mock_http, fixture_bytes, run_sync):
+async def test_currencies_in_use_are_requested_besides_the_always_quoted_pair(
+    app, mock_http, fixture_bytes, run_sync
+):
     await make_account(currency="RUB")
-    await make_account(currency="USD", source_id="usd-cash")
-    await make_txn(date(2026, 9, 1), outcome="100", outcome_currency="USD")
+    await make_account(currency="JPY", source_id="jpy-cash")
+    await make_txn(date(2026, 9, 1), outcome="100", outcome_currency="JPY")
 
     _, dynamic = mock_cbr(mock_http, fixture_bytes)
     result = await run_sync(CbrSource(), settings=settings())
 
     requested = {params["VAL_NM_RQ"] for params in route_params(dynamic)}
-    assert requested == {USD_ID}  # EUR and JPY are quoted by CBR but unused here
-    assert result.counts == {"currencies": 1, "rates": 3}
+    assert requested == {USD_ID, CNY_ID, JPY_ID}  # EUR is quoted by CBR, but nobody uses it
+    assert result.counts["currencies"] == 3
     assert result.warnings == []
     assert result.changed is True
     assert result.cursor_after is not None
@@ -88,13 +95,13 @@ async def test_currency_cbr_does_not_quote_is_a_warning(app, mock_http, fixture_
     _, dynamic = mock_cbr(mock_http, fixture_bytes)
     result = await run_sync(CbrSource(), settings=settings())
 
-    assert {params["VAL_NM_RQ"] for params in route_params(dynamic)} == {USD_ID}
+    assert {params["VAL_NM_RQ"] for params in route_params(dynamic)} == {USD_ID, CNY_ID}
     assert sorted(result.warnings) == [
         "BTC is not quoted by CBR — skipped (crypto or metal?)",
         "XAU is not quoted by CBR — skipped (crypto or metal?)",
     ]
-    assert result.counts["currencies"] == 1
-    assert result.counts["rates"] == 3
+    assert result.counts["currencies"] == 2
+    assert result.counts["rates"] == 6
 
 
 async def test_range_starts_before_the_first_transaction(app, mock_http, fixture_bytes, run_sync):
@@ -129,15 +136,43 @@ async def test_cursor_shortens_the_range_and_reruns_are_idempotent(
     assert params["date_req1"] == expected_start.strftime("%d/%m/%Y")
 
 
-async def test_no_foreign_currency_skips_the_network(app, mock_http, fixture_bytes, run_sync):
+async def test_the_dollar_and_the_yuan_are_fetched_even_with_only_roubles(
+    app, mock_http, fixture_bytes, run_sync
+):
+    """A currency that shows up in ZenMoney between two runs must already have its rate."""
     await make_account(currency="RUB")
     daily, dynamic = mock_cbr(mock_http, fixture_bytes)
 
     result = await run_sync(CbrSource(), settings=settings())
 
-    assert not daily.called and not dynamic.called
-    assert result.changed is False
-    assert result.counts == {"currencies": 0, "rates": 0}
+    assert daily.called
+    assert {params["VAL_NM_RQ"] for params in route_params(dynamic)} == {USD_ID, CNY_ID}
+    assert result.changed is True
+    assert result.counts == {"currencies": 2, "rates": 6}
+    rates = await stored_rates()
+    assert rates[("CNY", "2026-09-03")] == (1, Decimal("12.7654"))
+
+
+async def test_a_currency_new_to_the_table_is_backfilled_from_the_start_of_the_ledger(
+    app, mock_http, fixture_bytes, run_sync
+):
+    """The cursor only knows what the other currencies have; a new one needs its whole past."""
+    first = today_local() - timedelta(days=10)
+    await make_account(currency="USD", source_id="usd")
+    await make_txn(first, outcome="10", outcome_currency="USD")
+    _, dynamic = mock_cbr(mock_http, fixture_bytes)
+    earlier = await run_sync(CbrSource(), settings=settings())
+
+    await make_account(currency="JPY", source_id="jpy")
+    await make_txn(first + timedelta(days=2), outcome="1000", outcome_currency="JPY")
+    seen = len(dynamic.calls)
+    await run_sync(CbrSource(), settings=settings(), cursor=earlier.cursor_after)
+
+    starts = {p["VAL_NM_RQ"]: p["date_req1"] for p in route_params(dynamic)[seen:]}
+    incremental = date.fromisoformat(earlier.cursor_after or "") - timedelta(days=3)
+    assert starts[JPY_ID] == (first - timedelta(days=7)).strftime("%d/%m/%Y")
+    assert starts[USD_ID] == incremental.strftime("%d/%m/%Y")
+    assert starts[CNY_ID] == incremental.strftime("%d/%m/%Y")
 
 
 def test_long_ranges_are_chunked_by_year():