Validate and Resolve Chained Decision Rules

Problem Statement

You are building a rule engine for evaluating financial compliance. The system maintains a table of validation rules. Each rule is defined as a pair (rule_name, result):

• rule_name: A unique identifier for the rule.
• result: The outcome of the rule, which can be:
  • "pass": The rule succeeds.
  • "fail": The rule fails.
  • Another rule's name: The outcome of this rule delegates to the outcome of the referenced rule.

Write a function all_rules_pass(rules: list[tuple[str, str]]) -> bool that returns True if every rule in the table ultimately resolves to "pass". Return False if any rule:

• Resolves to "fail",
• Forms a circular dependency (cycle),
• References an unknown rule not present in the table.

Function Signature

def all_rules_pass(rules: list[tuple[str, str]]) -> bool:
    pass

Constraints

• 1 <= len(rules) <= 10^5
• rule_name is a non-empty string of alphanumeric characters (excluding "pass" and "fail").
• All rule_name entries in rules are distinct.
• result is a non-empty string of alphanumeric characters.

Examples

Example 1

rules = [
    ("RuleA", "RuleB"),
    ("RuleB", "RuleC"),
    ("RuleC", "pass"),
    ("RuleD", "RuleC")
]
# Output: True
# Explanation: RuleA -> RuleB -> RuleC -> pass.
# RuleD -> RuleC -> pass. All rules resolve to "pass".

Example 2

rules = [
    ("KYC", "AML"),
    ("AML", "KYC"),
    ("Sanctions", "pass")
]
# Output: False
# Explanation: "KYC" and "AML" form an infinite cycle.

Example 3

rules = [
    ("CreditCheck", "IncomeCheck"),
    ("IncomeCheck", "fail")
]
# Output: False
# Explanation: Both rules resolve to "fail".

Example 4

rules = [
    ("Rule1", "Rule2"),
    ("Rule2", "UnknownRule")
]
# Output: False
# Explanation: "Rule2" references "UnknownRule", which is not defined.