What causes "min_version is invalid: %s" in hashicorp/packer?

Set min_version to a plain version string, e.g. `min_version = "1.7.0"`

min_version is invalid: %s

Error message

min_version is invalid: %s

What it means

Thrown by Core.validate() at packer/core.go:870 when the template declares a `min_version` that HashiCorp go-version cannot parse. Packer validates the declared minimum required Packer version, and an unparseable string (not a valid semver-like version) fails before any comparison happens.

Source

Thrown at packer/core.go:870

// richer semantic checks around variables and so on.
func (c *Core) validate() error {
	// First validate the template in general, we can't do anything else
	// unless the template itself is valid.
	if err := c.Template.Validate(); err != nil {
		return err
	}

	// Validate the minimum version is satisfied
	if c.Template.MinVersion != "" {
		versionActual, err := version.NewVersion(c.version)
		if err != nil {
			// This shouldn't happen since we set it via the compiler
			panic(err)
		}

		versionMin, err := version.NewVersion(c.Template.MinVersion)
		if err != nil {
			return fmt.Errorf(
				"min_version is invalid: %s", err)
		}

		if versionActual.LessThan(versionMin) {
			return fmt.Errorf(
				"This template requires Packer version %s or higher; using %s",
				versionMin,
				versionActual)
		}
	}

	// Validate variables are set
	var err error
	for n, v := range c.Template.Variables {
		if v.Required {
			if _, ok := c.variables[n]; !ok {
				err = multierror.Append(err, fmt.Errorf(
					"required variable not set: %s", n))

View on GitHub (pinned to eb36e3c3e4)

Solutions

Set min_version to a plain version string, e.g. `min_version = "1.7.0"`
Remove any leading 'v', comparators, ranges, or non-numeric suffixes from the value
Remove the min_version attribute entirely if version pinning is not needed

Example fix

// before
min_version = ">= 1.7.0"
// after
min_version = "1.7.0"

Defensive patterns

Strategy: validation

Validate before calling

# ensure min_version parses before invoking packer
grep -oP 'min_version\s*=\s*"\K[^"]+' *.pkr.hcl | grep -vP '^\d+\.\d+\.\d+$' && echo 'invalid min_version found'

Prevention

Use plain x.y.z strings for min_version (no 'v', no comparators, no ranges)
Let CI run `packer validate` to catch malformed version constraints early
Distinguish required_version (supports constraints) from min_version (plain version) when writing templates

When it happens

Trigger: Core.validate() (called from Core.initialize during GetBuilds) sees c.Template.MinVersion != "" and version.NewVersion(MinVersion) returns an error — the string is not a valid version like "1.7.0".

Common situations: Writing `min_version = "v1.7.0"` with a leading 'v' in contexts where it is unsupported; using ranges or comparators (">= 1.7") instead of a plain version; typos like "1..7" or "latest"; copying an HCL required_version constraint into the min_version field.

Related errors

AI-assisted analysis of hashicorp/packer@eb36e3c3e4 (2026-09-05). Data as JSON: /api/errors/5e2a28b438a02871. Report an issue: GitHub.