Type SQLExpression and spark expr() as LiteralString#540
Open
NickCrews wants to merge 1 commit into
Open
Conversation
Encourages static detection of SQL injection: passing a dynamically built string to SQLExpression() or the spark expr() function now fails typechecking unless explicitly suppressed. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Motivation
SQLExpression() (and the pyspark-compat expr(), which wraps it) parse raw SQL, so passing a string built from untrusted input is an injection risk. PEP 675's LiteralString lets type checkers catch this statically: literal strings and compositions of literals pass, while dynamically constructed strings are flagged.
##Changes
_duckdb-stubs/init.pyi: SQLExpression(expression: str) → SQLExpression(expression: LiteralString)
duckdb/experimental/spark/sql/functions.py: expr(str: str) → expr(str: LiteralString) (annotation and docstring)
tests/fast/test_sql_expression.py: test showing a dynamically built string still works at runtime but requires a # type: ignore[arg-type] to pass typechecking
Notes
Runtime behavior is unchanged — this only affects static typing. Users who intentionally build SQL dynamically can suppress with # type: ignore[arg-type] (mypy) or cast.
🤖 Generated with Claude Code