walkPkgs(filepath.Join(cfg.GOROOTsrc, "cmd"), "cmd", pruneGoMod)
		}
	}

	if cfg.BuildMod == "vendor" {
		for _, mod := range MainModules.Versions() {
			if modRoot := MainModules.ModRoot(mod); modRoot != "" {
				walkPkgs(modRoot, MainModules.PathPrefix(mod), pruneGoMod|pruneVendor)
			}
		}
		if HasModRoot() {
			walkPkgs(VendorDir(), "", pruneVendor)
		}
		return
	}

					return module.Version{}, MainModules.ModRoot(mainModule), dir, nil, err
				} else if ok {
					return mainModule, MainModules.ModRoot(mainModule), dir, nil, nil
				}
			}
		}
		dir := filepath.Join(cfg.GOROOTsrc, path)
		modroot = cfg.GOROOTsrc
		if str.HasPathPrefix(path, "cmd") {
			modroot = filepath.Join(cfg.GOROOTsrc, "cmd")
		}

# Test a replacement with an absolute path (so the path isn't
# cleaned by having filepath.Abs called on it). This checks
# whether the modindex logic cleans the modroot path before using
# it.

[!GOOS:windows] skip
[short] skip

go run print_go_mod.go # use this program to write a go.mod with an absolute path
cp stdout go.mod

go list -modfile=go.mod all
-- print_go_mod.go --
//go:build ignore
package main

import (
    "fmt"

	os.Setenv("PWD", altRoot)
	goCmd(nil, "build", "-buildmode=plugin", "-o", filepath.Join(modRoot, "plugin-mismatch.so"), "./plugin-mismatch")

	os.Setenv("GOPATH", GOPATH)
	if err := os.Chdir(modRoot); err != nil {
		log.Panic(err)
	} else {
		prettyPrintf("cd %s\n", modRoot)
	}
	os.Setenv("PWD", modRoot)

	os.Setenv("LD_LIBRARY_PATH", modRoot)

	goCmd(nil, "build", "-buildmode=plugin", "./plugin1")

	var goV string
	for _, m := range mms.Versions() {
		if mms.ModRoot(m) == "" && m.Path == "command-line-arguments" {
			// This is not a real module.
			// TODO(#49228): Remove this special case once the special
			// command-line-arguments module is gone.
			continue
		}

		// Use EnterModule to reset the global state in modload to be in
		// single-module mode using the modroot of m.
		modload.EnterModule(ctx, mms.ModRoot(m))

				modRoot := MainModules.ModRoot(v)
				if foundModRoot != "" && foundFrom != from && found != r {
					base.Errorf("conflicting replacements found for %v in workspace modules defined by %v and %v",
						mod, modFilePath(foundModRoot), modFilePath(modRoot))
					return found, foundModRoot, modFilePath(foundModRoot)
				}
				found, foundModRoot = r, modRoot
			}
		}
	}

		}
		if v, ok := rawGoVersion.Load(m); ok {
			info.GoVersion = v.(string)
		} else {
			panic("internal error: GoVersion not set for main module")
		}
		if modRoot := MainModules.ModRoot(m); modRoot != "" {
			info.Dir = modRoot
			info.GoMod = modFilePath(modRoot)
		}
		return info
	}

	info := &modinfo.ModulePublic{
		Path:     m.Path,
		Version:  m.Version,
		Indirect: rs != nil && !rs.direct[m.Path],

func cloneTestdataModule(gopath string) (string, error) {
	modRoot := filepath.Join(gopath, "src", "testshared")
	if err := cgotest.OverlayDir(modRoot, "testdata"); err != nil {
		return "", err
	}
	if err := os.WriteFile(filepath.Join(modRoot, "go.mod"), []byte("module testshared\n"), 0644); err != nil {
		return "", err
	}
	return modRoot, nil
}

		log.Fatal(err)
	}

	if os.Getenv("GO111MODULE") == "on" {
		out, err := exec.Command("go", "env", "GOMOD").Output()
		if err != nil {
			log.Fatal(err)
		}
		modRoot := filepath.Dir(strings.TrimSpace(string(out)))
		check(data, "module root", modRoot)
	} else {
		check(data, "GOPATH", os.Getenv("GOPATH"))
	}
	check(data, "GOROOT", os.Getenv("GOROOT"))
}

func check(data []byte, desc, dir string) {

		log.Panic(err)
	}
	defer os.RemoveAll(GOPATH)
	os.Setenv("GOPATH", GOPATH)

	modRoot := filepath.Join(GOPATH, "src", "testcshared")
	if err := cgotest.OverlayDir(modRoot, "testdata"); err != nil {
		log.Panic(err)
	}
	if err := os.Chdir(modRoot); err != nil {
		log.Panic(err)
	}
	os.Setenv("PWD", modRoot)
	if err := os.WriteFile("go.mod", []byte("module testcshared\n"), 0666); err != nil {
		log.Panic(err)