Error propagation
Error propagation is the transmission or spread of an error, failure, or its effects from an originating operation or stage to dependent computations, components, or later results.
Rust Servers, Services, and Apps
Error propagation is the technique of passing an operation's failure result to a caller so that a higher-level component can handle it.
- How it is used
- Routes database failures from course retrieval to an HTTP handler for production-oriented request handling.
- How deep it goes
- Contrasts unwrap() with ?, then applies Result signatures and error conversions without detailing Rust error internals.
- Examples
- Uses tutor course retrieval, SQLx queries, EzyTutorError conversions, curl requests, and handler tests.
- What you can do after
- Apply error propagation via Rust's question mark operator and custom From implementations in an Actix web service.
Read how Rust Servers, Services, and Apps explains error propagation →
Learn Go with Pocket-Sized Projects
Error propagation is the practice of passing an error to an upper program layer when the current layer cannot resolve it.
- How it is used
- Uses wrapped errors to move unresolved validation failures from helper functions to callers that can choose the response.
- How deep it goes
- Explains immediate error checks, contextual wrapping, caller behavior, and unit verification, stopping short of broader error-taxonomy design.
- Examples
- Demonstrates a word-length validator, a wrapped `fmt.Errorf` return, terminal error reporting, and `errors.Is` tests.
- What you can do after
- Build error-aware Go call chains that wrap unresolved failures, preserve their identity, and let callers respond appropriately.
Read how Learn Go with Pocket-Sized Projects explains error propagation →
Machine Learning Platform Engineering
Error propagation analysis identifies how failures introduced at one processing stage affect subsequent stages and final outputs.
- How it is used
- Separates failures across retrieval, context assembly, and generation to improve reliability in multistep LLM systems.
- How deep it goes
- Locates breakdowns across reasoning stages and traces tokens and branches, but does not specify recovery implementations.
- Examples
- Uses vacation-policy retrieval, indexed document chunks, and Langfuse spans across retrieval, augmentation, and generation.
- What you can do after
- Diagnose/debug with Langfuse by locating failures in retrieval, context assembly, or generation traces.
Read how Machine Learning Platform Engineering explains error propagation →
Kotlin in Action, 2E
Error propagation is the transmission of an error or exception from the computation where it occurs to an enclosing or related computation.
- How it is used
- Handles uncaught failures across coroutine hierarchies and provides a basis for controlling errors in coroutines and flows.
- How deep it goes
- Explains child-to-parent propagation and await() rethrowing, while deferring broader parent-handling strategies.
- Examples
- Uses async with await(), launch with try/catch, and UnsupportedOperationException examples.
- What you can do after
- Diagnose/debug with it by locating the parent responsible for an uncaught coroutine exception and choosing where to catch it.
Related concepts
- human-in-the-loopaddressed by · Human-in-the-loop is a system pattern in which people provide input, judgment, review, or intervention within an automated process.
- pipelineaddressed by · A pipeline is an ordered or coordinated sequence of connected processing stages or tasks that passes data, work, or results toward an outcome.
- exceptionused by · An exception is a runtime signal or object representing an abnormal condition that interrupts ordinary program flow and may be handled or propagated.
- resilienceaddressed by · Resilience is the capacity of a system or organization to withstand disruption, adapt, recover, or continue functioning acceptably.
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