[Bug] find_all_callers, find_all_callees, call_chain fail with "Unknown function list_extract" #756

Description

Three analyze_code_relationships query types fail with the same error on v0.3.1 with KùzuDB backend:

• find_all_callers
• find_all_callees
• call_chain

All return: Error executing relationship query: Unknown function 'list_extract'

Steps to Reproduce

pip install codegraphcontext==0.3.1
cgc index /path/to/any/project

Then via MCP or CLI:

codegraph_analyze_code_relationships(query_type="find_all_callers", target="any_function")
codegraph_analyze_code_relationships(query_type="find_all_callees", target="any_function")
codegraph_analyze_code_relationships(query_type="call_chain", target="funcA->funcB")

Expected Behavior

Transitive caller/callee graph and call chain paths should be returned (as documented in README).

Actual Behavior

{
  "error": "Error executing relationship query: Unknown function 'list_extract'",
  "query_type": "find_all_callers",
  "target": "any_function"
}

Root Cause Analysis

list_extract is not a built-in Cypher function in KùzuDB. It appears in Neo4j's APOC library. The Cypher queries for these three operations likely use list_extract() which is unavailable in the KùzuDB backend.

Note: find_callers (direct/non-transitive) works correctly. Only the transitive/recursive variants are broken.

Environment

• codegraphcontext: 0.3.1
• Database backend: KùzuDB (default)
• Python: 3.12.3
• OS: Linux (Ubuntu)