feat: pass calling SessionContext to Python UDTF callbacks#1555
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feat: pass calling SessionContext to Python UDTF callbacks#1555timsaucer wants to merge 1 commit into
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DataFusion 53 added `TableFunctionImpl::call_with_args(TableFunctionArgs)` where `TableFunctionArgs` carries both the positional expression arguments and the calling `&dyn Session`. The pure-Python UDTF path previously discarded everything but the exprs. Thread the session through when the user callback's signature opts in by declaring a `session` keyword parameter (or `**kwargs`). At call time we downcast the `&dyn Session` to its canonical `SessionState` impl and build a fresh `SessionContext` over the same Arc-shared state, exposed to Python as a `datafusion.SessionContext` wrapper. Existing callbacks whose signatures do not declare `session` continue to be called with the positional expression arguments only — no behavior change for current users. Note: a UDTF body cannot drive a fresh `ctx.sql(...).collect()` on the passed-in session because the outer SQL execution already holds the tokio runtime. Use the session for metadata access (catalogs, UDF lookups, config) rather than nested DataFrame collection. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Which issue does this PR close?
Related to #1533
Rationale for this change
Upstream DataFusion deprecated
call()on table functions so that we could support far more features. Instead we should usecall_with_args. That is already being done inmainusing default table function arguments. This PR exposes the full functionality of the function signature.What changes are included in this PR?
Are there any user-facing changes?
Yes, this changes the expected arguments to pure python table functions.