Fix property access on list comprehension / predicate loop variables

[MuhammadTahaNaveed]

transform_column_ref_for_indirection errored with could not find properties for <name> when the referenced RTE had no "properties" column (as is the case for the unnest() RTE used by list comprehension and the any/all/none/single predicate functions), breaking queries like [x IN list | x.name] and any(x IN list WHERE x.n > 1).

Return NULL instead so the caller continues transforming the ColumnRef as an agtype value and applies the indirection via agtype_access_operator.

[Copilot]

Pull request overview

Fixes Cypher property access (x.prop) on list-comprehension and predicate-function loop variables by avoiding an error path when the referenced RTE doesn’t have a properties column (e.g., unnest()-backed loop variables), allowing indirection to be applied via agtype_access_operator instead.

Changes:

• Update transform_column_ref_for_indirection to return NULL (instead of erroring) when a properties column is not present, enabling fallback indirection handling.
• Add regression coverage for property access on loop variables in any/all/none/single and list comprehensions.
• Update expected regression outputs accordingly.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/backend/parser/cypher_expr.c	Avoids hard error when properties column is missing; allows fallback transformation + indirection via agtype operators.
regress/sql/predicate_functions.sql	Adds regression queries for property access on predicate loop variables (maps + collected vertices).
regress/sql/list_comprehension.sql	Adds regression queries for property access on list-comprehension loop variables (maps + vertices).
regress/expected/predicate_functions.out	Captures expected results for the new predicate-function regression queries.
regress/expected/list_comprehension.out	Captures expected results for the new list-comprehension regression queries.

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