"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"sync"
	"testing"

	"cmd/go/internal/modfetch/codehost"
	"cmd/go/internal/par"

	"golang.org/x/mod/module"
	"golang.org/x/mod/semver"
	"golang.org/x/mod/sumdb"
	"golang.org/x/mod/sumdb/dirhash"
)

var (
	proxyAddr = flag.String("proxy", "", "run proxy on this network address instead of running any tests")
	proxyURL  string
)

	"GCCGOTOOLDIR",       // for gccgo testing
}

// updateSum runs 'go mod tidy', 'go list -mod=mod -m all', or
// 'go list -mod=mod all' in the test's current directory if a file named
// "go.mod" is present after the archive has been extracted. updateSum modifies
// archive and returns true if go.mod or go.sum were changed.

	C_PPAUTO_16   // 0 to 504, 0 mod 16
	C_PPAUTO      // 0 to 504, 0 mod 8
	C_PQAUTO_16   // 0 to 1008, 0 mod 16
	C_UAUTO4K_16  // 0 to 4095, 0 mod 16
	C_UAUTO4K_8   // 0 to 4095, 0 mod 8
	C_UAUTO4K_4   // 0 to 4095, 0 mod 4
	C_UAUTO4K_2   // 0 to 4095, 0 mod 2
	C_UAUTO4K     // 0 to 4095
	C_UAUTO8K_16  // 0 to 8190, 0 mod 16
	C_UAUTO8K_8   // 0 to 8190, 0 mod 8
	C_UAUTO8K_4   // 0 to 8190, 0 mod 4

		// command line. Recommend 'go mod download' for the modules that could
		// provide the package, since that shouldn't change go.mod.
		if len(e.mods) > 0 {
			args := make([]string, len(e.mods))
			for i, mod := range e.mods {
				args[i] = mod.Path
			}
			hint = fmt.Sprintf("; to add:\n\tgo mod download %s", strings.Join(args, " "))
		}
	} else {

					if info, err := os.Stat(gomod); err == nil && info.Mode().IsRegular() {
						m.GoMod = gomod
					}
				}
				if gomodsum, ok := modfetch.RecordedSum(modkey(mod)); ok {
					m.GoModSum = gomodsum
				}
			}
			if checksumOk("") {
				dir, err := modfetch.DownloadDir(ctx, mod)
				if err == nil {
					m.Dir = dir
				}
				if sum, ok := modfetch.RecordedSum(mod); ok {
					m.Sum = sum
				}
			}

	Short:     "edit go.mod from tools or scripts",
	Long: `
Edit provides a command-line interface for editing go.mod,
for use primarily by tools or scripts. It reads only go.mod;
it does not look up information about the modules involved.
By default, edit reads and writes the go.mod file of the main module,
but a different target file can be specified after the editing flags.

	},
	{
		// Git branch with a semver name, +incompatible version, and no go.mod file.
		vcs:  "git",
		path: "vcs-test.golang.org/go/mod/gitrepo1",
		rev:  "v2.3.4+incompatible",
		err:  `resolves to version v2.0.1+incompatible (v2.3.4 is not a tag)`,
	},
	{
		// Git branch with a semver name, matching go.mod file, and compatible version.
		vcs:  "git",
		path: "vcs-test.golang.org/git/semver-branch.git",

		indirect bool
	}
	need := make(map[string]elem)
	for _, r := range req {
		if prev, dup := need[r.Mod.Path]; dup && prev.version != r.Mod.Version {
			panic(fmt.Errorf("SetRequire called with conflicting versions for path %s (%s and %s)", r.Mod.Path, prev.version, r.Mod.Version))
		}
		need[r.Mod.Path] = elem{r.Mod.Version, r.Indirect}
	}

	// Update or delete the existing Require entries to preserve

		}
	}

	// Not v2/go.mod, so it's either go.mod or nothing. Which is it?
	if found1 {
		// Explicit go.mod with matching major version ok.
		return rev, r.codeDir, gomod1, nil
	}
	if err1 == nil {
		// Explicit go.mod with non-matching major version disallowed.
		suffix := ""
		if file2 != "" {
			suffix = fmt.Sprintf(" (and ...%s/go.mod does not exist)", r.pathMajor)
		}
		if mpath1 == "" {

	if modload.WorkFilePath() != "" {
		base.Fatalf("go: 'go mod vendor' cannot be run in workspace mode. Run 'go work vendor' to vendor the workspace or set 'GOWORK=off' to exit workspace mode.")
	}
	RunVendor(ctx, vendorE, vendorO, args)
}

func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string) {
	if len(args) != 0 {
		base.Fatalf("go: 'go mod vendor' accepts no arguments")
	}
	modload.ForceUseModules = true