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

A host provider cannot be registered with the ID

Error message

A host provider cannot be registered with the ID '{ProviderIdAuto}'

What it means

HostProviderRegistry.Register rejects any IHostProvider whose Id equals the reserved value 'auto' (Constants.ProviderIdAuto, compared OrdinalIgnoreCase). 'auto' is reserved for the automatic host-detection provider, so a custom provider claiming that ID would conflict with built-in detection. The library throws ArgumentException naming the offending parameter.

Solutions

1. Set the provider's Id property to a unique, non-'auto' constant (e.g. "mycompany")
2. Check provider.Id before registering and fail fast with a clear message
3. If the provider is meant to be chosen automatically, do not register it manually — rely on detection via SupportedAuthorityIds

Example fix

// before
var provider = new MyHostProvider { Id = Constants.ProviderIdAuto };
registry.Register(provider, HostProviderPriority.Normal); // throws
// after
var provider = new MyHostProvider { Id = "mycompany" };
registry.Register(provider, HostProviderPriority.Normal);

if (string.Equals(provider.Id, "auto", StringComparison.OrdinalIgnoreCase))
    throw new ArgumentException("Provider Id must not be the reserved value 'auto'", nameof(provider));

bool HasValidProviderId(IHostProvider p) => !string.IsNullOrWhiteSpace(p.Id) && !p.Id.Equals("auto", StringComparison.OrdinalIgnoreCase);

try
{
    registry.Register(provider, HostProviderPriority.Normal);
}
catch (ArgumentException ex)
{
    logger.LogError(ex, "Provider registration rejected: {Message}", ex.Message);
}

When it happens

Trigger: Calling hostProviderRegistry.Register(provider, priority) where provider.Id == "auto" (any casing).

Common situations: Writing a custom host provider and forgetting to set a unique Id, copying sample code that leaves the default/placeholder ID 'auto', or programmatic provider injection in tests.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• A host provider cannot be registered with the legacy…
• Must specify at least one AuthenticationModes
• Argument cannot be empty or white space.
• Argument must be an absolute URI.
• Argument must be positive or zero (non-negative).

AI-assisted analysis of git-ecosystem/git-credential-manager@e8ce762cd0 (2026-09-11). Data as JSON: /api/errors/4081507b4b19c809. Report an issue: GitHub.

Appendix: source

Thrown at src/Core/HostProviderRegistry.cs:70

    {
        private readonly ICommandContext _context;
        private readonly IDictionary<HostProviderPriority, ICollection<IHostProvider>> _hostProviders;

        public HostProviderRegistry(ICommandContext context)
        {
            EnsureArgument.NotNull(context, nameof(context));

            _context = context;
            _hostProviders = new Dictionary<HostProviderPriority, ICollection<IHostProvider>>();
        }

        public void Register(IHostProvider hostProvider, HostProviderPriority priority)
        {
            EnsureArgument.NotNull(hostProvider, nameof(hostProvider));

            if (StringComparer.OrdinalIgnoreCase.Equals(hostProvider.Id, Constants.ProviderIdAuto))
            {
                throw new ArgumentException(
                    $"A host provider cannot be registered with the ID '{Constants.ProviderIdAuto}'",
                    nameof(hostProvider));
            }

            if (hostProvider.SupportedAuthorityIds.Any(y => StringComparer.OrdinalIgnoreCase.Equals(y, Constants.AuthorityIdAuto)))
            {
                throw new ArgumentException(
                    $"A host provider cannot be registered with the legacy authority ID '{Constants.AuthorityIdAuto}'",
                    nameof(hostProvider));
            }

            if (!_hostProviders.TryGetValue(priority, out ICollection<IHostProvider> providers))
            {
                providers = new List<IHostProvider>();
                _hostProviders[priority] = providers;
            }

            providers.Add(hostProvider);

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