rethrowing

Rethrowing is the practice of catching an exception, performing local handling such as logging or resource cleanup, and then propagating the same exception to higher levels of the program. It allows targeted processing at one layer while still delegating the ultimate error response to a broader context.

Rethrowing can preserve the original error context, which aids debugging, or be used to add context by wrapping the original exception in a new one. The choice between rethrowing the same exception and wrapping it affects how much information survives the propagation and how easily a caller can interpret the failure. In many languages, rethrowing the same exception keeps the original stack trace intact, while wrapping creates a new exception with the previous one as its cause, adding a layer of interpretation.

Language-specific notes: In Java, a common pattern is to catch an exception, perform some work (like logging), and rethrow the same exception (for example, throw e;), or throw a new exception that includes the original one as a cause. In C#, rethrowing with throw; preserves the original stack trace, while throw ex; would replace it. In C++, rethrowing the current exception is typically done with throw;, which preserves the original traceback. In Python, a re-raise is done with raise (inside an except block) to preserve the traceback, while creating a new exception involves raising a new object explicitly.

Related concepts include exception chaining, where a new exception is linked to the original, and exception swallowing, where exceptions are caught and not propagated. Rethrowing practices influence error reporting, maintainability, and the clarity of fault isolation in software systems.