coreybutler/nvm-windows · error

Invalid character(s) found in build meta data %q

Error message

Invalid character(s) found in build meta data %q

What it means

Semver parse error: a dot-separated identifier in the build metadata (the part after '+' in MAJOR.MINOR.PATCH-pre+build) contains characters outside [0-9A-Za-z]. Build identifiers must be alphanumeric per SEMVER 2.0.0; hyphens and other symbols are not allowed there.

Source

Thrown at src/semver/semver.go:277

		for _, prstr := range prparts {
			parsedPR, err := NewPRVersion(prstr)
			if err != nil {
				return nil, err
			}
			v.Pre = append(v.Pre, parsedPR)
		}
	}

	// There is build meta data
	if buildIndex != -1 {
		buildStr := parts[2][buildIndex+1:]
		buildParts := strings.Split(buildStr, ".")
		for _, str := range buildParts {
			if len(str) == 0 {
				return nil, errors.New("Build meta data is empty")
			}
			if !containsOnly(str, alphanum) {
				return nil, fmt.Errorf("Invalid character(s) found in build meta data %q", str)
			}
			v.Build = append(v.Build, str)
		}
	}

	return v, nil
}

// PreRelease Version
type PRVersion struct {
	VersionStr string
	VersionNum uint64
	IsNum      bool
}

// Creates a new valid prerelease version
func NewPRVersion(s string) (*PRVersion, error) {
	if len(s) == 0 {

View on GitHub (pinned to 5b18223ca1)

Solutions

1. Sanitize build metadata to alphanumerics and dots only (replace '_'/'-' with '.')
2. Drop the build metadata before parsing — semver precedence ignores it: parse s[:strings.IndexByte(s,'+')]
3. Fix the CI job that stamps non-alphanumeric characters into build metadata

Example fix

// before
v, err := semver.NewVersion("1.2.3+linux_x64")

// after
v, err := semver.NewVersion("1.2.3+linux.x64")

func sanitizeBuild(v string) string {
    if i := strings.IndexByte(v, '+'); i >= 0 {
        meta := strings.Map(func(r rune) rune {
            if (r >= '0' && r <= '9') || (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') || r == '.' { return r }
            return '.'
        }, v[i+1:])
        return v[:i+1] + meta
    }
    return v
}

When it happens

Trigger: semver.NewVersion("1.2.3+build-1"), "1.2.3+linux_x64", or any '+'-suffix where an identifier between dots contains '_', '-', or other non-alphanumerics.

Common situations: Versions enriched with platform tags using underscores (common from CI build metadata), or build hashes with dashes concatenated into the metadata.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Invalid character(s) found in patch number %q
• Patch number must not contain leading zeroes %q
• Invalid character(s) found in prerelease %q
• Numeric PreRelease version must not contain leading zeroes %
• Unrecognized version: "%s"

AI-assisted analysis of coreybutler/nvm-windows@5b18223ca1 (2026-08-15). Data as JSON: /api/errors/194ee65f30ebf372. Report an issue: GitHub.