git-ecosystem/git-credential-manager · error · ArgumentException

Argument must be an absolute URI.

Error message

Argument must be an absolute URI.

What it means

This ArgumentException is thrown by EnsureArgument.AbsoluteUri when a Uri argument is not an absolute URI (i.e., it is relative, such as "/api/items" or lacks a scheme). The library requires absolute URIs so it can resolve endpoints without a base address. The parameter name is included in the exception.

Solutions

1. Ensure the Uri has a scheme and host (e.g., prefix "https://" if missing) before passing it
2. Use Uri.TryCreate(value, UriKind.Absolute, out var uri) to validate the value at parse time
3. Fix the configuration or caller supplying a relative path; combine a relative path with a base Uri via new Uri(baseUri, relative)
4. Verify with uri.IsAbsoluteUri before calling the API

Example fix

// before
var uri = new Uri(config.Endpoint); // relative: "api/items"
EnsureArgument.AbsoluteUri(uri, nameof(uri));
// after
if (!Uri.TryCreate(config.Endpoint, UriKind.Absolute, out var uri))
    throw new InvalidOperationException($"Endpoint '{config.Endpoint}' is not an absolute URI");
EnsureArgument.AbsoluteUri(uri, nameof(uri));

if (!Uri.TryCreate(raw, UriKind.Absolute, out var uri))
    throw new InvalidOperationException($"'{raw}' is not an absolute URI (scheme required)");

static bool IsAbsoluteUri(string? raw) => Uri.TryCreate(raw, UriKind.Absolute, out _);

try { EnsureArgument.AbsoluteUri(endpoint, nameof(endpoint)); }
catch (ArgumentException ex) when (ex.ParamName == nameof(endpoint))
{
    throw new ConfigurationErrorsException($"Endpoint must be an absolute URI, got '{endpoint}'", ex);
}

When it happens

Trigger: Calling EnsureArgument.AbsoluteUri(arg, name) when arg is a relative Uri such as new Uri("api/items", UriKind.Relative) or new Uri("/path"), or when a base-URI-dependent Uri was constructed without a scheme like "https://".

Common situations: Building a client with a config value that omitted the scheme ("myhost:8080" instead of "https://myhost:8080"); concatenating path fragments into a Uri; a config migration dropping the scheme.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

• Not a valid URI
• Must specify at least one AuthenticationModes
• Argument cannot be empty or white space.
• Argument must be positive or zero (non-negative).
• Argument must be positive.

AI-assisted analysis of git-ecosystem/git-credential-manager@e8ce762cd0 (2026-09-11). Data as JSON: /api/errors/efe03cf5347435a9. Report an issue: GitHub.

Appendix: source

Thrown at src/Core/EnsureArgument.cs:41

        }

        public static void NotNullOrWhiteSpace(string arg, string name)
        {
            NotNull(arg, name);

            if (string.IsNullOrWhiteSpace(arg))
            {
                throw new ArgumentException("Argument cannot be empty or white space.", name);
            }
        }

        public static void AbsoluteUri(Uri arg, string name)
        {
            NotNull(arg, name);

            if (!arg.IsAbsoluteUri)
            {
                throw new ArgumentException("Argument must be an absolute URI.", name);
            }
        }

        public static void PositiveOrZero(int arg, string name)
        {
            if (arg < 0)
            {
                throw new ArgumentOutOfRangeException(name, "Argument must be positive or zero (non-negative).");
            }
        }

        public static void Positive(int arg, string name)
        {
            if (arg <= 0)
            {
                throw new ArgumentOutOfRangeException(name, "Argument must be positive.");
            }
        }

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