Snowflake converter turns a query source with a leading comment into a fake table

[barveP]

If a dataset's source is a SQL query that starts with a comment, the Snowflake converter doesn't notice it's a query. It splits the text on dots, uppercases the pieces, and emits them as a physical table. No error, no warning.

Here's the smallest example. This is valid Ossie; the spec says source can be a table name or a query.

- name: orders
  source: |
    -- revenue source
    SELECT amount FROM db.schema.orders

Running it through convert_ossie_to_snowflake gives:

base_table:
  database: "-- REVENUE SOURCE\nSELECT AMOUNT FROM DB"
  schema: SCHEMA
  table: ORDERS

The expected output is base_table: {definition: <the query>}, which is what Snowflake documents for query-backed tables.

The same thing happens with a /* */ comment, with a query wrapped in parentheses, with SELECT*FROM (no space), and with \r\n after SELECT or WITH. Reproduced on main at 50457d3.

Why

_parse_source in converters/snowflake/src/ossie_snowflake/converter.py decides "query or table" with one check:

upper.startswith(("SELECT ", "SELECT\n", "SELECT\t", "WITH ", "WITH\n", "WITH\t"))

Anything that doesn't match is assumed to be a table name. That path accepts any three dot-separated chunks without checking they're identifiers, so SQL text gets chopped up and emitted as database.schema.table.

Where else

The Honeydew converter has the same check and labels the query as a table. The NVIDIA converter has it too; its "must be a physical table" guard is bypassed by the comment, and it emits the same fake table. The Omni converter uses a word-boundary regex and raises a clear error instead, which is the right behavior when unsure.

Proposed fix

Two small changes, per converter:

1. Skip leading whitespace, -- and /* */ comments, and opening parentheses before looking for SELECT or WITH, and match the keyword as a whole word. Keep the query text exactly as written.
2. On the table path, require each of the three parts to be a real identifier (plain or double-quoted). If not, raise instead of uppercasing it.

This is independent of the structured source work in #109 / #173 / #338, which all keep string sources supported.

I have a patch for the Snowflake converter with tests (all existing tests pass, 18 added) and can follow up for Honeydew and NVIDIA. Happy to open the PR if this sounds right.