Go Error Handling Evolution and AsA Proposals

Sep 10 2025 golang 12 minutes read (About 1772 words)

Simplifying Error Handling: Is It Possible?

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Note: The core content was generated by an LLM, with human fact-checking and structural refinement.

Go’s error handling mechanism, particularly since the introduction of errors.Is and errors.As in Go 1.13, has aimed for a structured and traceable approach. However, despite its intentional design, it remains one of the most debated and controversial features of the language, often cited as the most common problem in surveys after generics were added. This ongoing discussion highlights a tension between the Go community’s desire for improvement and a strong inclination to maintain the language’s core philosophies.

Current State Challenges

The primary challenge and most frequent complaint regarding Go’s error handling is its verbosity and the repetitive boilerplate code. The pattern if err != nil { return err } is ubiquitous, appearing “countless” times across codebases, as evidenced by GitHub searches.

This verbosity leads to several issues:

Reduced Readability: Many developers find that the constant error checks obscure the main logic of a function, making the code “significantly harder to pick out what the method is actually doing”. Some describe it as “taxing” to visually scan past these repetitive lines.
Unergonomic errors.As Usage: The current errors.As method requires developers to predeclare a variable of the target error type, then pass a pointer to it. This is considered “unergonomic,” boilerplate, causes variable scope leakage, and resembles C-language style “output parameters” rather than Go’s idiomatic multiple return values.

Current errors.As pattern:
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err := foo()
if err != nil {
var myErr *MyCustomError
if errors.As(err, &myErr) { // myErr's scope extends beyond this block
// handle myErr
}
// ...
}
Developer Frustration: The perceived lack of progress on error handling improvements leads to bitterness and a feeling of “eternal deadlock” for some community members. The explicit handling can be seen as “tedious and clumsy”.

Common boilerplate example:
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err := doSomethingTowardMyActualGoal()
if err != nil {
return err
}
err = doTheNextInterestingThing()
if err != nil {
return err
}
// ... actual logic ...
Lack of Stack Traces: Some users also identify the lack of stack traces as a significant pain point for debugging.

Arguments for the Current Approach

Despite the challenges, many Go developers and language designers staunchly defend the current error handling philosophy, citing several key advantages:

Explicitness and Accountability: Go’s approach forces developers to explicitly deal with errors, promoting “a flow of accountability”. This provides “peace of mind” and prevents errors from being silently ignored or causing unexpected control flow issues, as can happen with exceptions.
Clarity and Troubleshooting: The explicit nature makes it “suuuuuper clear where and how your program might break,” which simplifies troubleshooting. It aids readability in “side paths and edge cases,” which are often the most critical and complex parts of the code, rather than just the “happy path”.
Intentional Design: The current system is a “very intentional language design feature”, fundamentally rooted in the belief that error values offer better semantics than exceptions.
Simplicity: The system is considered simple enough for beginners while providing the necessary building blocks for complex error handling, aligning with the “Keep It Simple” philosophy.
Avoids Pitfalls of Exceptions: Critics of exceptions argue they hide control flow, unwind the stack, lose relevant context, and lead to frequently unhandled errors in other languages. Go’s approach aims to avoid these issues.
Not a DRY Violation: Some argue that the repetitive if err != nil { return err } pattern does not violate the “Don’t Repeat Yourself” (DRY) principle, as each error check, even if syntactically similar, pertains to a “fundamentally different thing” or operation.
Advanced Features: Go has seen improvements like errors.Join(), and some argue that errors.Is and errors.As provide a significant advantage for complex error handling that other languages lack.

Proposed Improvements and Alternatives

The community has proposed numerous ways to improve Go’s error handling, with many suggestions drawing inspiration from other languages:

Syntactic Sugar for Propagation: The most common request is for a shorthand to simplify the boilerplate if err != nil { return err }.
- Rust’s ? operator: This is frequently cited as an ideal solution for concise error propagation. A proposed Go equivalent might look like value, ? := myfunc(…), where ? would automatically handle propagation.
- Single-line conditionals: Allowing if err != nil return err could reduce vertical space.
- New operators: Ideas include adding ! to a function call to signify “return error if not nil”.

Generics for errors.As (IsA/AsA): A significant proposal (Issue #51945) suggests a new type-parameterized function, AsA, to replace the current errors.As pattern.

Benefits: This AsA function would offer improved ergonomics by allowing a “comma, ok” pattern familiar to Go developers, confine error variables to their necessary scope, provide compile-time type safety (preventing runtime panics from incorrect target types), and deliver significant performance boosts (50-70% faster) by avoiding reflection and reducing heap allocations.

Proposed errors.AsA pattern:

err := someOperation()
if err != nil {
    if myErr, ok := errors.AsA[*MyCustomError](err); ok { // myErr's scope is within this block
        // handle myErr
    } else if otherErr, ok := errors.AsA[*OtherError](err); ok {
        // handle otherErr
    }
    // handle everything else
}

Challenges: The main drawback is that AsA‘s (_ E, ok bool) return signature doesn’t integrate as elegantly with switch statements as the current errors.As. Despite this, the proposal has gained traction and is in the “Active” review stage.

try Keyword: Inspired by languages like Zig, some proposals suggest a try keyword, potentially for Go 2.
- A more elaborate try proposal includes an implicit goto to a catch: label within the current function, allowing for error annotation or recovery, possibly with a new errors.Annotate() function. However, some argue against immediate return behavior from try if it discourages error annotation.

Misconceptions/Debunked Ideas

Throughout the debate, certain arguments and beliefs about Go’s error handling have been challenged:

“Boilerplate violates DRY”: While the code snippets are similar, some argue that each if err != nil { return err } is a distinct check for a specific operation, making it a reuse of a programming construct rather than a violation of DRY.
“You don’t have to use it” as a justification for new features: This argument is largely rejected, as new language features tend to “infect” open-source and team code, effectively forcing developers to engage with them.
“Go community was against generics”: While some individuals opposed generics, the broader sentiment was to find a solution consistent with Go’s design philosophy, which ultimately happened.
“Happy path readability is paramount”: Proponents of Go’s explicit error handling argue that making the “happy path” overly succinct is a “clever code trap.” Instead, Go prioritizes the readability of “side paths and edge cases,” which are often more complex and critical for debugging.
“Go’s error handling is more verbose than correct error handling in other languages”: It’s argued that while Go’s explicit checks might seem verbose, proper error handling in languages like Java (including throws declarations, try blocks, and finally clauses) often results in more lines of code and can still lead to unhandled exceptions.
Braceless Conditionals: While a shorthand like if err != nil return err might reduce verbosity, it is opposed by some who see braceless conditionals as security hazards and grammar complications.

User Experience

The user experience with Go’s error handling is highly subjective and varied:

Positive Sentiment: Many developers express satisfaction, finding it “straightforward,” “linear,” “reliable,” and “easy to read and reason about”. The explicitness provides “peace of mind” and helps in quickly identifying potential break points.
Challenges for Newcomers: Error handling is frequently cited as a “challenge” for those new to Go, especially when coming from languages that use exceptions.
Controversy: The issue remains deeply controversial, with strong opinions on both sides. Some users feel the Go community can be dogmatic in its resistance to change.
Tooling Assistance: Tools like GitHub Copilot are noted to alleviate the burden of typing out boilerplate.
Impact on Code Logic: For some, the verbosity “gets in the way of understanding the main logic of the code”.
External Library Issues: Difficulties can arise when dealing with underlying libraries that return non-exported error types, forcing less ideal string-based error checking.

The “Gofmt’s style is no one’s favorite, yet gofmt is everyone’s favorite” proverb is sometimes applied to Go’s error handling, suggesting that while no one might love it perfectly, it serves a beneficial purpose for the community. Ultimately, many developers accept that no language will perfectly meet all their desires, finding appreciation for Go as it is.

Links to quoted articles:

GitHub search for boilerplate:
- https://github.com/search?q=%22if+err+%21%3D+nil+%7B+return+err+%7D%22&type=code
Go blog survey results:
- https://go.dev/blog/survey2022-q2-results
errors.As with type parameters GitHub issue:
- https://github.com/golang/go/issues/51945
Rust error handling documentation:
- https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#propagating-errors
- https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
Medium article on DRY misconception:
- https://medium.com/@erfangc/the-reusability-myth-59a370f60da

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中文文章: https://programmerscareer.com/zh-cn/go-errors-asa/
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Note: Originally written at https://programmerscareer.com/go-errors-asa/ at 2025-09-10 11:19.
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