Bug: unified_search fails with "Variable 'd' not defined" error for Project and Task nodes

[tyfta]

🐛 Bug Report

Problem Description

The unified_search function fails with a Cypher query error when searching for Project and Task nodes:

Variable d not defined (line 11, column 44 (offset: 275))
" WHEN 'Knowledge' THEN (CASE WHEN d IS NOT NULL THEN d.name ELSE null END)"

Root Cause

In src/services/neo4j/searchService/unifiedSearchLogic.ts:

1. Variable scope issue in returnClause (lines 181-183):

   • Variable d is used for all node types in the CASE statement
   • But d is only defined in optionalMatches for Knowledge nodes
   • This causes Cypher query errors for Project and Task searches

2. Missing variable definitions in baseWithVariables (lines 235-240):

   • Variables p, k_proj, d are not properly added to baseWithVariables
   • This can cause issues with variable availability in Cypher queries

Impact

• Function unified_search returns 0 results for all searches
• Critical functionality broken for project and task management
• Affects all MCP clients using Atlas

Expected Behavior

• unified_search should work for all node types (Project, Task, Knowledge)
• No Cypher query errors
• Proper search results returned

Steps to Reproduce

1. Start Atlas MCP server
2. Try unified_search with any value
3. Observe error in logs and 0 results returned

Proposed Solution

Fix the variable scope issues in the Cypher query:

1. Fix returnClause:

CASE $label
  WHEN '${NodeLabels.Knowledge}' THEN (CASE WHEN d IS NOT NULL THEN d.name ELSE null END)
  WHEN '${NodeLabels.Project}' THEN n.taskType
  WHEN '${NodeLabels.Task}' THEN n.taskType
  ELSE n.taskType 
END AS entityType,

2. Fix baseWithVariables:

let baseWithVariables = ["n"];
if (actualLabel === NodeLabels.Task && assignedToUserIdFilter) {
  baseWithVariables.push("assignee");
}
if (actualLabel === NodeLabels.Task) {
  baseWithVariables.push("p");
}
if (actualLabel === NodeLabels.Knowledge) {
  baseWithVariables.push("k_proj", "d");
}
baseWithVariables = [...new Set(baseWithVariables)];

Environment

• Atlas MCP Server version: 2.8.15
• Neo4j version: 5.x
• Node.js version: 18+

Labels

• bug
• high-priority
• unified-search
• neo4j

[onestardao]

Thanks for the clear root-cause notes. This looks like Problem Map #6 – Logic Collapse & Recovery: the query path dead-ends because d isn’t carried/defined across branches, so unified_search returns 0 (or errors) for certain node types.

Quick sanity checks that typically fix this class:

In returnClause/CASE branches: make sure d is introduced before it’s referenced (e.g., via a prior WITH … d or by binding it in every OPTIONAL MATCH path).

In baseWithVariables: include all variables used later (p, k, proj, d) so they’re available post-WITH.

If mixing optional branches, prefer a single normalization step (e.g., WITH coalesce(d_from_A, d_from_B) AS d, …) before the final RETURN.

If helpful, I can share a 1-page Semantic Firewall checklist we use for #6 (from my “60-day / 600-star” Problem Map work) that catches missing/late-bound vars and WITH-scope drops in query pipelines. Want me to drop that here?