golang/go · error

multiple meta tags match import path %q

Error message

multiple meta tags match import path %q

What it means

In matchGoImport, two (or more) non-'mod' meta-import entries both have prefixes that cover the requested import path. mod entries sort first and short-circuit, so this only fires for genuine duplicates among non-mod VCS entries.

Source

Thrown at src/cmd/go/internal/vcs/vcs.go:1223

// An ImportMismatchError is returned if none match.
func matchGoImport(imports []metaImport, importPath string) (metaImport, error) {
	match := -1

	errImportMismatch := ImportMismatchError{importPath: importPath}
	for i, im := range imports {
		if !str.HasPathPrefix(importPath, im.Prefix) {
			errImportMismatch.mismatches = append(errImportMismatch.mismatches, im.Prefix)
			continue
		}

		if match >= 0 {
			if imports[match].VCS == "mod" && im.VCS != "mod" {
				// All the mod entries precede all the non-mod entries.
				// We have a mod entry and don't care about the rest,
				// matching or not.
				break
			}
			return metaImport{}, fmt.Errorf("multiple meta tags match import path %q", importPath)
		}
		match = i
	}

	if match == -1 {
		return metaImport{}, errImportMismatch
	}
	return imports[match], nil
}

// expand rewrites s to replace {k} with match[k] for each key k in match.
func expand(match map[string]string, s string) string {
	// We want to replace each match exactly once, and the result of expansion
	// must not depend on the iteration order through the map.
	// A strings.Replacer has exactly the properties we're looking for.
	oldNew := make([]string, 0, 2*len(match))
	for k, v := range match {
		oldNew = append(oldNew, "{"+k+"}", v)

View on GitHub (pinned to b6b368adc5)

Solutions

1. Publish a single go-import meta tag per module root with the longest applicable prefix
2. Remove redundant per-subpackage meta tags

// Reject vanity pages that emit more than one matching non-mod prefix
func oneMatchPerPath(imports []metaImport) error {
  seen := map[string]int{}
  for _, im := range imports {
    if im.VCS == "mod" { continue }
    seen[im.Prefix]++
  }
  for p, n := range seen { if n > 1 { return fmt.Errorf("duplicate prefix %s", p) } }
  return nil
}

When it happens

Trigger: Page lists e.g. 'example.com/foo git ...' and 'example.com/foo/bar git ...' and the import path is 'example.com/foo/bar' — both prefixes match.

Common situations: Vanity server emitting one tag per subpackage instead of one per module root; templating bug producing duplicate tags.

Related errors

• parse %s: %v
• parse %s: no go-import meta tags (%s)
• %s and %s disagree about go-import for %s
• %s: invalid subdirectory %q: %v
• %s: invalid repo root %q: %v

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/a07349606a9c54af. Report an issue: GitHub.