Explicit error handling

Always handle error conditions explicitly rather than silently ignoring them or using generic error responses. Use specific error codes that reflect business logic rather than low-level system errors, and throw exceptions for unexpected states instead of using assertions or returning generic failure indicators.

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Prompt

Reviewer Prompt
Deploy Agent

Always handle error conditions explicitly rather than silently ignoring them or using generic error responses. Use specific error codes that reflect business logic rather than low-level system errors, and throw exceptions for unexpected states instead of using assertions or returning generic failure indicators.

Key principles:

  1. Throw specific exceptions for unexpected conditions rather than using assertions that can cause segfaults
  2. Use business-logic error codes instead of generic system-level codes to provide better context
  3. Explicitly check expected error conditions and throw exceptions for unexpected ones
  4. Avoid silent failures - parse and validate inputs completely, throwing unsupported exceptions for unhandled cases

Example of good explicit error handling:

// Instead of silent failure or generic error
if (code != Coordination::Error::ZOK)
    return false;  // BAD: silently ignores all error types

// Be explicit about expected vs unexpected errors
if (code == Coordination::Error::ZNONODE || code == Coordination::Error::ZNOAUTH)
    return false;  // Expected errors
else if (Coordination::isHardwareError(code))
    throw Exception(ErrorCodes::ZOOKEEPER_EXCEPTION, "Hardware error: {}", code);  // Unexpected errors

// Use specific error codes that reflect business context
throw Exception(ErrorCodes::UDF_EXECUTION_FAILED, "UDF execution failed: {}", details);
// Instead of generic: ErrorCodes::CANNOT_WRITE_TO_FILE_DESCRIPTOR

// Replace assertions with proper exceptions
chassert(tuple_function->arguments->children.size() == partition_columns.size());  // BAD
if (tuple_function->arguments->children.size() != partition_columns.size())
    throw Exception(ErrorCodes::LOGICAL_ERROR, "Partition argument count mismatch");  // GOOD

This approach improves debugging, provides better user experience, and prevents silent corruption of program state.

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