Implement Robust Error Handling Patterns

Contrasts four error-handling philosophies - exceptions for unexpected or exceptional conditions, Result types for expected errors like validation failures, C-style error codes requiring discipline, and Option or Maybe types for nullable values - against panics and crashes reserved for unrecoverable errors, and separates recoverable errors (network timeouts, missing files, invalid input, rate limits) from unrecoverable ones (out of memory, stack overflow, programming bugs). Documents language-specific error handling for Python, TypeScript and JavaScript, Rust (the ? operator propagating Result errors, a custom AppError enum implementing Fromio::Error for automatic conversion, Option for nullable lookups, and combining Option and Result via ok_or_else), and Go (wrapped errors with fmt.Errorf's %w verb, a custom ValidationError implementing the error interface, sentinel errors like ErrNotFound compared with errors.Is, and unwrapping with errors.As). Ships three universal patterns: a circuit breaker - a CircuitBreaker class cycling through CLOSED, OPEN, and HALF_OPEN states based on a failure_threshold and timeout, rejecting calls while OPEN and testing recovery in HALF_OPEN before a success_threshold closes it again, to prevent cascading failures in distributed systems; error aggregation - an ErrorCollector that gathers multiple errors instead of failing on the first one, throwing a single error directly or an AggregateError when more than one accumulated; and graceful degradation with multiple fallback layers. Closes with a good-error-handling example, best practices, and common pitfalls.

Use it when choosing an error-handling strategy for a language, implementing a circuit breaker for a distributed system, aggregating multiple errors instead of failing fast, or designing graceful degradation with fallbacks. Skip it for anything unrelated to error handling or outside this scope.

Input is an error-handling decision - which philosophy fits a given error, a language-specific implementation need, or a resilience pattern for a failing dependency; output is the matching code: a Rust Result chain, a Go wrapped-error function, a circuit breaker class, an error collector, or a fallback chain.

Language-native mechanisms only - Rust's Result and Option with the ? operator, Go's error interface with errors.Is and errors.As, and Python and TypeScript exception handling - with the circuit breaker, aggregation, and degradation patterns implemented as plain classes with no external dependency.

Engineers designing error-handling strategy across one or more languages who need concrete per-language patterns and resilience mechanisms like circuit breakers rather than an abstract exceptions-versus-error-codes debate to resolve on their own.