# hashicorp/go-multierror

A Go (golang) package for representing a list of errors as a single error.

Repository: https://github.com/hashicorp/go-multierror
Canonical: https://ross.abutalabs.com/products/go-multierror
Language: Go
License: MPL-2.0
License Family: copyleft
Last push: 2026-07-06T14:32:51+00:00

## Health v2 (maintenance only)
Score: 73/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 91, release rhythm 35, longevity 100
- inputs: {"age_days": 4279, "days_push": 58, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2580, forks 144 (observed 2026-08-28T04:07:02.400964+00:00)

## What it is
A Go package that represents a list of error values as a single error, with human-readable formatting and utilities like Append, Flatten, Prefix, and a concurrent Group pattern. It is now in maintenance mode since Go 1.20's errors.Join covers basic aggregation.

## Use cases
- combine multiple errors into one return value in Go
- collect errors from concurrent goroutines
- format a list of errors readably
- append errors while iterating over operations
- flatten nested error lists

## When to choose
- you need custom error formatting or Prefix/Flatten helpers
- you need concurrent error collection via Group
- you're maintaining an existing codebase already using it

## When to avoid
- starting a new Go project that only needs basic error joining (use errors.Join)
- you only need the first error from concurrent tasks (use errgroup)

## Facets
- artifact type: library
- maturity: maintenance
- function: error-handling, concurrency
- domain: developer-tools, backend
- platform: go, cross-platform
- tags: error-aggregation, multierror, errors-join, golang

## Member repositories
- hashicorp/go-multierror (main) score 73

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:02.400964+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:22:38.518790+00:00, confidence not recorded.
  - readme: https://github.com/hashicorp/go-multierror (fetched 2026-08-28T04:07:02.400964+00:00, sha faca2951e9b7)
- Data as of 2026-08-30T08:39:29.467469+00:00.