Module: SqlChatbot::Grammar::SanityCheck

Defined in:
lib/sql_chatbot/grammar/sanity_check.rb

Overview

Post-execution sanity check for grammar-generated SQL.

Catches “plausible but wrong” results where the SQL ran without error but the value disagrees with the registry’s known row count. Concrete case: Gitea’s ‘user` reserved-word table returned 1 instead of 9.

Class Method Summary collapse

Class Method Details

.check_count(primitive, entity, result_rows) ⇒ Object

Returns { ok: true } when result matches expectations, or { ok: false, reason: “…” } when there’s a mismatch.



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# File 'lib/sql_chatbot/grammar/sanity_check.rb', line 13

def self.check_count(primitive, entity, result_rows)
  return { ok: true } unless primitive.to_s == "COUNT"
  return { ok: true } unless result_rows.is_a?(Array) && result_rows.length == 1

  row = result_rows.first
  v = row.is_a?(Hash) ? row.values.first : nil
  got = Integer(v.to_s) rescue nil
  return { ok: true } unless got

  expected = entity.row_count.to_i
  # Trust the registry only when it has a non-trivial value.
  # Tables with reltuples == 0 might just be stats-stale.
  return { ok: true } if expected <= 5

  if got < expected / 3 || got > expected * 3
    return {
      ok: false,
      reason: "count_mismatch: SQL returned #{got}, registry has ~#{expected} rows in #{entity.table}",
    }
  end
  { ok: true }
end