charmbracelet/glow · error

invalid url: %s

Error message

invalid url: %s

What it means

findGitLabREADME mirrors the GitHub path parsing: it cuts the trimmed URL path on the first '/' to get owner and project. With fewer than two path segments, ok is false and this error reports the full URL before any request is made. It is a URL-shape validation failure only.

Source

Thrown at gitlab.go:17

package main

import (
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
)

// findGitLabREADME tries to find the correct README filename in a repository using GitLab API.
func findGitLabREADME(u *url.URL) (*source, error) {
	owner, repo, ok := strings.Cut(strings.TrimPrefix(u.Path, "/"), "/")
	if !ok {
		return nil, fmt.Errorf("invalid url: %s", u.String())
	}

	projectPath := url.QueryEscape(owner + "/" + repo)

	type readme struct {
		ReadmeURL string `json:"readme_url"`
	}

	apiURL := fmt.Sprintf("https://%s/api/v4/projects/%s", u.Hostname(), projectPath)

	//nolint:bodyclose
	// it is closed on the caller
	res, err := http.Get(apiURL) //nolint: gosec,noctx
	if err != nil {
		return nil, fmt.Errorf("unable to get url: %w", err)
	}

	body, err := io.ReadAll(res.Body)

View on GitHub (pinned to e3970c813d)

Solutions

1. Use the full project URL: https://gitlab.com/OWNER/PROJECT
2. When constructing URLs in code, require both owner and project to be non-empty
3. Navigate into an actual project page before copying the URL

Example fix

# before
glow https://gitlab.com/mygroup   # group page, no project

# after
glow https://gitlab.com/mygroup/myproject

func isGitLabProjectURL(u *url.URL) bool {
	if u == nil || (u.Host != "gitlab.com" && !strings.HasSuffix(u.Host, ".gitlab.com")) {
		return false
	}
	_, _, ok := strings.Cut(strings.TrimPrefix(u.Path, "/"), "/")
	return ok
}

if !isGitLabProjectURL(u) {
	return fmt.Errorf("expected https://gitlab.com/OWNER/PROJECT, got %s", u)
}

src, err := findGitLabREADME(u)
if err != nil && strings.Contains(err.Error(), "invalid url") {
	// deterministic shape failure — do not retry; request a proper project URL
	return nil, fmt.Errorf("need owner/project URL like https://gitlab.com/OWNER/PROJECT: %w", err)
}
return src, err

When it happens

Trigger: Passing https://gitlab.com alone; a user or group page like https://gitlab.com/mygroup; a project URL with an empty project segment; hand-built URLs where the project component is blank.

Common situations: Copying a group/subgroup landing page instead of a project; scripts templating the project field from an empty variable; truncated pastes.

Related errors

• invalid url: %s
• unable to parse url: %w
• %s is not a supported protocol
• can't find README in GitLab repository
• cannot use both pager and tui

AI-assisted analysis of charmbracelet/glow@e3970c813d (2026-08-15). Data as JSON: /api/errors/c549c1ebf003daf0. Report an issue: GitHub.