# Go Concurrency
# Detects map writes inside goroutines, often indicating unsafe shared mutation.
id: go-shared-map-write-goroutine
name: Shared Map Write in Goroutine
severity: error
category: concurrency
defect_class: async-misuse
inline_tier: blocking
language: go

message: "Map write inside goroutine may race — guard with synchronization or ownership boundaries"

description: |
  Native Go maps are not safe for concurrent writes without synchronization.

  ✅ FIX: use sync.Mutex/RWMutex, channels, or sync.Map based on access patterns.

query: |
  (go_statement
    expression: (call_expression
      function: (func_literal
        body: (block
          (assignment_statement
            left: (index_expression) @MAPWRITE
            right: (_) @VALUE)))
      arguments: (argument_list) @ARGS))

metavars:
  - MAPWRITE
  - VALUE
  - ARGS

cwe:
  - CWE-362
owasp:
  - A09
confidence: medium

has_fix: false

tags:
  - go
  - concurrency
  - map
  - race

examples:
  bad: |
    go func() { m[key] = value }()

  good: |
    mu.Lock()
    m[key] = value
    mu.Unlock()