feat(python-migrate): R6 — field.float emits REAL; stringify REAL/DOUBLE on the wire

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: dmealing

server/python/src/metaobjects/migrate/expected_schema.py

@@ -25,6 +25,7 @@
     Json,
     Numeric,
     Real,
+    Real4,
     SqlType,
     Text,
     Timestamp,
@@ -116,8 +117,10 @@ def _subtype_to_sql_type(field: MetaField) -> SqlType:
         return Integer(bits=32)
     if st in (fc.FIELD_SUBTYPE_LONG, fc.FIELD_SUBTYPE_CURRENCY):
         return Integer(bits=64)
-    if st in (fc.FIELD_SUBTYPE_DOUBLE, fc.FIELD_SUBTYPE_FLOAT):
+    if st == fc.FIELD_SUBTYPE_DOUBLE:
         return Real()
+    if st == fc.FIELD_SUBTYPE_FLOAT:
+        return Real4()
     if st == fc.FIELD_SUBTYPE_DECIMAL:
         return Numeric()
     if st == fc.FIELD_SUBTYPE_BOOLEAN:

server/python/src/metaobjects/migrate/postgres_emit.py

@@ -15,6 +15,7 @@
     Json,
     Numeric,
     Real,
+    Real4,
     SqlType,
     Text,
     Timestamp,
@@ -125,6 +126,8 @@ def _pg_type(t: SqlType) -> str:
         return "BIGINT" if t.bits == 64 else "INTEGER"
     if isinstance(t, Real):
         return "DOUBLE PRECISION"
+    if isinstance(t, Real4):
+        return "REAL"
     if isinstance(t, Numeric):
         if t.precision is not None and t.scale is not None:
             return f"NUMERIC({t.precision},{t.scale})"

server/python/src/metaobjects/migrate/sql_type.py

@@ -24,6 +24,11 @@ class Real:
     kind: Literal["real"] = field(default="real", init=False)
 
 
+@dataclass(frozen=True)
+class Real4:
+    kind: Literal["real4"] = field(default="real4", init=False)
+
+
 @dataclass(frozen=True)
 class Numeric:
     precision: int | None = None
@@ -62,4 +67,4 @@ class Uuid:
     kind: Literal["uuid"] = field(default="uuid", init=False)
 
 
-SqlType = Union[Text, Integer, Real, Numeric, Boolean, Timestamp, Date, Json, Blob, Uuid]
+SqlType = Union[Text, Integer, Real, Real4, Numeric, Boolean, Timestamp, Date, Json, Blob, Uuid]

server/python/tests/integration/normalization.py

@@ -31,7 +31,7 @@ def normalize_value(v: Any) -> Any:
         # PKs as strings, so this gives stable cross-port output without overreach.
         return str(v) if v > 2**31 - 1 or v < -(2**31) else v
     if isinstance(v, float):
-        return v
+        return _canonical_float(v)
     if isinstance(v, decimal.Decimal):
         return _canonical_decimal(v)
     if isinstance(v, uuid.UUID):
@@ -83,6 +83,20 @@ def _canonical_decimal(d: decimal.Decimal) -> str:
     return s
 
 
+def _canonical_float(x: float) -> str:
+    # In-band dyadic values (per normalization.md) render plain + shortest via repr().
+    s = repr(x)
+    if "e" in s or "E" in s:
+        raise ValueError(
+            f"_canonical_float: {x} is outside the plain-decimal band (exponential "
+            "notation); REAL/DOUBLE fixture values must be in-band dyadic rationals — "
+            "see fixtures/persistence-conformance/normalization.md"
+        )
+    if "." in s:
+        s = s.rstrip("0").rstrip(".")
+    return s
+
+
 def _ms_suffix(microseconds: int) -> str:
     if microseconds == 0:
         return ""