}

var fetchGroup singleflight.Group
var (
	fetchCacheMu sync.Mutex
	fetchCache   = map[string]fetchResult{} // key is metaImportsForPrefix's importPrefix
)

// metaImportsForPrefix takes a package's root import path as declared in a <meta> tag
// and returns its HTML discovery URL and the parsed metaImport lines
// found on the page.
//
// The importPath is of the form "golang.org/x/tools".

// pipelines, or redirections typically done by shells. The package
// behaves more like C's "exec" family of functions. To expand glob
// patterns, either call the shell directly, taking care to escape any
// dangerous input, or use the [path/filepath] package's Glob function.
// To expand environment variables, use package os's ExpandEnv.
//
// Note that the examples in this package assume a Unix system.

}

func loadPkgs(patterns ...string) ([]*packages.Package, error) {
	cfg := packages.Config{
		Mode: packages.NeedName | packages.NeedFiles | packages.NeedImports |
			packages.NeedDeps | packages.NeedModule,
		Tests: true,
	}

	klog.V(1).Infof("loading: %v", patterns)
	tBefore := time.Now()
	pkgs, err := packages.Load(&cfg, patterns...)
	if err != nil {
		return nil, err
	}

	`,
}

var HelpPackages = &base.Command{
	UsageLine: "packages",
	Short:     "package lists and patterns",
	Long: `
Many commands apply to a set of packages:

	go <action> [packages]

Usually, [packages] is a list of import paths.

An import path that is a rooted path or that begins with
a . or .. element is interpreted as a file system path and
denotes the package in that directory.

	// i.e., locally vendored packages may not be found.
	// The types package does not call Import if an ImporterFrom
	// is present.
	Importer

	// ImportFrom returns the imported package for the given import
	// path when imported by a package file located in dir.
	// If the import failed, besides returning an error, ImportFrom
	// is encouraged to cache and return a package anyway, if one

//
// The //go:embed directive can be used with both exported and unexported variables,
// depending on whether the package wants to make the data available to other packages.
// It can only be used with variables at package scope, not with local variables.
//
// Patterns must not match files outside the package's module, such as ‘.git/*’ or symbolic links.

// and a1.Deps is the actions for building packages directly imported by
// package main (what the compiler needs). The linker needs all packages
// transitively imported by the whole program; addTransitiveLinkDeps
// makes sure those are present in a.Deps.
// If shlib is non-empty, then a corresponds to the build and installation of shlib,

		// imports. TestStdlib will collect errors once for each package.
		return pkg, nil
	}
	return nil, err
}

// getDirPackage gets the package defined in dir from the future cache.
//
// If this is the first goroutine requesting the package, getDirPackage
// type-checks.
func (c *stdlibChecker) getDirPackage(dir string) (*Package, error) {
	c.mu.Lock()
	fut, ok := c.pkgs[dir]
	if !ok {

	}
	return append(ldflags, "-extld="+joined), nil
}

// pluginPath computes the package path for a plugin main package.
//
// This is typically the import path of the main package p, unless the
// plugin is being built directly from source files. In that case we
// combine the package build ID with the contents of the main package
// source files. This allows us to identify two different plugins

// Existing packages should not have their constraints relaxed
// without prior discussion.
// Negative assertions should almost never be removed.
//
// "a < b" means package b can import package a.
//
// See `go doc internal/dag' for the full syntax.
//
// All-caps names are pseudo-names for specific points
// in the dependency lattice.
var depsRules = `
	# No dependencies allowed for any of these packages.
	NONE
	< unsafe