bug: Mapped datetime values are typed as strings in the schema message

[edgarrmondragon]

Singer SDK Version

0.26.0

Is this a regression?

• Yes

Python Version

NA

Bug scope

Mapping (stream maps, flattening, etc.)

Operating System

NA

Description

When generating a datetime value from a string using stream map functionality, e.g.

stream_maps:
  my_stream:
    created: datetime.datetime.from_timestamp(createdAt)

the detected schema type for the value falls back to string.

sdk/singer_sdk/mapper.py

Lines 372 to 379 in 33d64c8

	if expr.startswith("float("):
	return NumberType()
	if expr.startswith("int("):
	return IntegerType()
	if expr.startswith("str("):
	return StringType()

Code

No response

[dluo-sig]

Another similar issue in CustomStreamMap:

                existing_schema: dict = (
                    # Use transformed schema if available
                    transformed_schema["properties"].get(prop_key, {})
                    # ...or original schema for passthrough
                    or self.raw_schema["properties"].get(prop_def, {})
                )

If the stream map is defined using _['columnName'] or record['columnName'], the type mapping falls back to string because it doesn't look at the underlying column name, but rather treats the entire expression as the column that it's searching for. prop_def should check for that specification and pass through the appropriate column name.

[edgarrmondragon]

@dluo-sig Can you open a new issue for this? It is related, but I think it is a distinct 🐛.