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Clarify exists() function: property existence only, not graph patterns#397

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Clarify exists() function: property existence only, not graph patterns#397
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copilot/update-exists-pattern-documentation

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Copilot AI commented Mar 21, 2026 •
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exists(pattern) docs implied arbitrary graph patterns are supported. In practice, only property existence checks work — e.g. exists(n.prop). Passing relationship patterns like exists((n)-[]-()) errors out.

  • Changed signature from exists(_pattern_) to exists(_entity.property_) to reflect actual behavior
  • Updated description to "Returns true when the specified property exists on a given node or relationship"
  • Added note that graph patterns are unsupported, linking to FalkorDB#1315 and pointing users to pattern predicates in WHERE as the alternative
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This section details on the original issue you should resolve

<issue_title>Clarify exists(pattern) function limitations</issue_title>
<issue_description>## Context

Migrated from FalkorDB/FalkorDB#1315.

Issue

The functions documentation describes the exists() predicate function as:

exists(pattern) — Returns true when at least one match for pattern exists

This implies that any graph pattern is supported. However, in practice, attempting to use exists() with a relationship pattern returns an error:

GRAPH.QUERY g "MATCH (n) WHERE exists((n)-[]-()) RETURN *"
(error) Unable to resolve filtered alias '(n)-[]-()'

Verified on FalkorDB v4.16.7 — the error still occurs.

Suggested Fix

Either:

  1. Update the docs to clarify what pattern types exists() actually supports (e.g., only property existence checks like exists(n.prop), or only specific pattern forms), or
  2. Note this as a known limitation and link to the related bug in the FalkorDB repo.

The WHERE clause docs show that pattern predicates work in WHERE directly (e.g., WHERE (p)-[:WON]->(s)), so users may be confused about why the same pattern doesn't work inside exists().</issue_description>

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@gkorland
docs: clarify exists() only supports property existence checks, not g…
bf1f6cb 
…raph patterns

Co-authored-by: gkorland <753206+gkorland@users.noreply.github.com>
Agent-Logs-Url: https://github.com/FalkorDB/docs/sessions/ed50614f-198b-49bd-80b3-5173ee41bbaf
Copilot AI changed the title [WIP] Update documentation to clarify exists(pattern) function limitations Clarify exists() function: property existence only, not graph patterns Mar 21, 2026
Copilot AI requested a review from gkorland March 21, 2026 21:59
@gkorland gkorland requested review from Copilot and swilly22 March 21, 2026 22:48
@gkorland gkorland marked this pull request as ready for review March 21, 2026 22:48
Copilot AI reviewed Mar 21, 2026
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Pull request overview

Updates the Cypher functions reference to accurately document FalkorDB’s exists() predicate as a property-existence check (not an arbitrary graph pattern existence predicate), and guides users to the correct alternative for graph-pattern filtering.

Changes:

  • Adjusted the documented signature from exists(_pattern_) to exists(_entity.property_).
  • Updated the description to clarify it checks for property existence on nodes/relationships.
  • Added a note that graph patterns are unsupported in exists(), linking to FalkorDB#1315 and pointing to WHERE pattern predicates.

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@gkorland gkorland Awaiting requested review from gkorland

@swilly22 swilly22 Awaiting requested review from swilly22

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Clarify exists(pattern) function limitations

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