Core's Double renders as bare DOUBLE, which Firebird's parser rejects, so the table is never created

[ChrisGVE]

Versions

• SQLAlchemy 2.0.51, Python 3.12.9, macOS
• Server: firebirdsql/firebird:5, LI-V5.0.4.1812 Firebird 5.0, engine version 5.0.4 from RDB$GET_CONTEXT('SYSTEM','ENGINE_VERSION')

What happens

Core's Double is rendered as a bare DOUBLE, which isn't a keyword Firebird has. The parser is waiting for PRECISION, so it fails on whatever comes next and no table is created:

SQL error code = -104
Token unknown - line 4, column 1
)

I compiled the same metadata against both Firebird dialects to see whether it was specific to one port. It isn't — both emit the same thing, so it looks like the shared base.py lineage rather than either fork:

type asked for	sqlalchemy-firebirdsql 0.1.0	sqlalchemy-firebird 2.2.0	stored / read back	reflected as
Double	DOUBLE	DOUBLE	table not created	—
DOUBLE_PRECISION	DOUBLE PRECISION	—	0.1 → 0.1, exact	DOUBLE PRECISION
Float(53)	FLOAT(53)	—	0.1 → 0.1, exact	DOUBLE PRECISION

Worth being clear about

This is the dialect, not Firebird. Firebird holds an 8-byte float perfectly well once it's asked in its own words — both workarounds above land in the same column and round-trip exactly. I'm recording it on my side as a client-library defect so nobody later goes looking for it in the database.

Suggested fix

Render Double as DOUBLE PRECISION. visit_DOUBLE currently emits the type name verbatim; Firebird needs the two-word spelling.

Workaround for anyone who lands here in the meantime: use DOUBLE_PRECISION from the dialect rather than Core's Double. Float(53) also works and ends up in the same column, but DOUBLE_PRECISION says what it means.