var readModGraphDebugOnce sync.Once

// readModGraph reads and returns the module dependency graph starting at the
// given roots.
//
// The requirements of the module versions found in the unprune map are included
// in the graph even if they would normally be pruned out.
//
// Unlike LoadModGraph, readModGraph does not attempt to diagnose or update
// inconsistent roots.

	for {
		mg, err = readModGraph(ctx, rootPruning, roots, upgradedRoot)
		// We keep on going even if err is non-nil until we reach a steady state.
		// (Note that readModGraph returns a non-nil *ModuleGraph even in case of
		// errors.) The caller may be able to fix the errors by adjusting versions,