/**
     * Select all toolchains available in user settings matching the type and requirements,
     * independently from <code>maven-toolchains-plugin</code>.
     *
     * @param session the Maven session, must not be {@code null}
     * @param type the type, must not be {@code null}
     * @param requirements the requirements, may be {@code null}
     * @return the matching toolchains, never {@code null}
     * @since 3.3.0

        List<ToolchainModel> models = session.getRequest().getToolchains().get(type);

        return selectToolchains(models, type, requirements);
    }

    private List<Toolchain> selectToolchains(
            List<ToolchainModel> models, String type, Map<String, String> requirements) {
        List<Toolchain> toolchains = new ArrayList<>();

    /**
     * Let the toolchain decide if it matches requirements defined
     * in the toolchain plugin configuration.
     * @param requirements Map<String, String> key value pair, may not be {@code null}
     * @return {@code true} if the requirements match, otherwise {@code false}
     */
    boolean matchesRequirements(Map<String, String> requirements);

    /**
     *

    /**
     * Let the toolchain decide if it matches requirements defined
     * in the toolchain plugin configuration.
     *
     * @param requirements key value pair, may not be {@code null}
     * @return {@code true} if the requirements match, otherwise {@code false}
     */
    boolean matchesRequirements(Map<String, String> requirements);

# When we set -mod=mod, the go version should be updated immediately,
# to the current version, converting the requirements from eager to lazy.
#
# Since we don't know which requirements are actually relevant to the main
# module, all requirements are added as roots, making the requirements untidy.

go list -mod=mod all
! stdout '^example.com/testdep$'
cmp stdout list-1.txt
cmpenv go.mod go.mod.untidy

    public List<Toolchain> getToolchains(Session session, String type, Map<String, String> requirements)
            throws ToolchainManagerException {
        MavenSession s = InternalMavenSession.from(session).getMavenSession();
        List<org.apache.maven.toolchain.Toolchain> toolchains =
                toolchainManagerPrivate.getToolchains(s, type, requirements);
        return new MappedList<>(toolchains, this::toToolchain);
    }

package mvs

import (
	"fmt"
	"strings"

	"golang.org/x/mod/module"
)

// BuildListError decorates an error that occurred gathering requirements
// while constructing a build list. BuildListError prints the chain
// of requirements to the module where the error occurred.
type BuildListError struct {
	Err   error
	stack []buildListErrorElem
}

type buildListErrorElem struct {
	m module.Version

			}
		}
	}
}

// FindPath reports a shortest requirement path starting at one of the roots of
// the graph and ending at a module version m for which f(m) returns true, or
// nil if no such path exists.
func (g *Graph) FindPath(f func(module.Version) bool) []module.Version {
	// firstRequires[a] = b means that in a breadth-first traversal of the
	// requirement graph, the module version a was first required by b.

			err = commitRequirements(ctx, WriteOpts{})
		}
	}
	return mods, err
}

func listModules(ctx context.Context, rs *Requirements, args []string, mode ListMode, reuse map[module.Version]*modinfo.ModulePublic) (_ *Requirements, mods []*modinfo.ModulePublic, mgErr error) {
	if len(args) == 0 {
		var ms []*modinfo.ModulePublic
		for _, m := range MainModules.Versions() {

        provides.put(type, matcher);
    }

    @Override
    public boolean matchesRequirements(Map<String, String> requirements) {
        for (Map.Entry<String, String> requirement : requirements.entrySet()) {
            String key = requirement.getKey();

            RequirementMatcher matcher = provides.get(key);

            if (matcher == null) {