cmd/go: using strings.CutPrefix replace strings.HasPrefix and strings.TrimPrefix

Change-Id: I143d05c24a3e897d0f3ee78dd16954c32ceae091
Reviewed-on: https://go-review.googlesource.com/c/go/+/435137
Run-TryBot: xie cui <523516579@qq.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>

src/cmd/go/internal/envcmd/env.go

@@ -453,8 +453,8 @@ func printEnvAsJSON(env []cfg.EnvVar) {
 
 func getOrigEnv(key string) string {
 	for _, v := range cfg.OrigEnv {
-		if strings.HasPrefix(v, key+"=") {
-			return strings.TrimPrefix(v, key+"=")
+		if v, found := strings.CutPrefix(v, key+"="); found {
+			return v
 		}
 	}
 	return ""

src/cmd/go/internal/modfetch/codehost/git.go

@@ -486,9 +486,9 @@ func (r *gitRepo) stat(rev string) (info *RevInfo, err error) {
 	// Either way, try a local stat before falling back to network I/O.
 	if !didStatLocal {
 		if info, err := r.statLocal(rev, hash); err == nil {
-			if strings.HasPrefix(ref, "refs/tags/") {
+			if after, found := strings.CutPrefix(ref, "refs/tags/"); found {
 				// Make sure tag exists, so it will be in localTags next time the go command is run.
-				Run(r.dir, "git", "tag", strings.TrimPrefix(ref, "refs/tags/"), hash)
+				Run(r.dir, "git", "tag", after, hash)
 			}
 			return info, nil
 		}

src/cmd/go/internal/modfetch/coderepo.go

@@ -1095,14 +1095,16 @@ func (r *codeRepo) Zip(dst io.Writer, version string) error {
 			}
 			topPrefix = zf.Name[:i+1]
 		}
-		if !strings.HasPrefix(zf.Name, topPrefix) {
+		var name string
+		var found bool
+		if name, found = strings.CutPrefix(zf.Name, topPrefix); !found {
 			return fmt.Errorf("zip file contains more than one top-level directory")
 		}
-		name := strings.TrimPrefix(zf.Name, topPrefix)
-		if !strings.HasPrefix(name, subdir) {
+
+		if name, found = strings.CutPrefix(name, subdir); !found {
 			continue
 		}
-		name = strings.TrimPrefix(name, subdir)
+
 		if name == "" || strings.HasSuffix(name, "/") {
 			continue
 		}

src/cmd/go/internal/modload/load.go

@@ -548,13 +548,12 @@ func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (str
 		modRoot := MainModules.ModRoot(mainModule)
 		if modRoot != "" && strings.HasPrefix(absDir, modRoot+string(filepath.Separator)) && !strings.Contains(absDir[len(modRoot):], "@") {
 			suffix := filepath.ToSlash(absDir[len(modRoot):])
-			if strings.HasPrefix(suffix, "/vendor/") {
+			if pkg, found := strings.CutPrefix(suffix, "/vendor/"); found {
 				if cfg.BuildMod != "vendor" {
 					return "", fmt.Errorf("without -mod=vendor, directory %s has no package path", absDir)
 				}
 
 				readVendorList(mainModule)
-				pkg := strings.TrimPrefix(suffix, "/vendor/")
 				if _, ok := vendorPkgModule[pkg]; !ok {
 					return "", fmt.Errorf("directory %s is not a package listed in vendor/modules.txt", absDir)
 				}

src/cmd/go/internal/modload/vendor.go

@@ -98,16 +98,16 @@ func readVendorList(mainModule module.Version) {
 				continue
 			}
 
-			if strings.HasPrefix(line, "## ") {
+			if annonations, ok := strings.CutPrefix(line, "## "); ok {
 				// Metadata. Take the union of annotations across multiple lines, if present.
 				meta := vendorMeta[mod]
-				for _, entry := range strings.Split(strings.TrimPrefix(line, "## "), ";") {
+				for _, entry := range strings.Split(annonations, ";") {
 					entry = strings.TrimSpace(entry)
 					if entry == "explicit" {
 						meta.Explicit = true
 					}
-					if strings.HasPrefix(entry, "go ") {
-						meta.GoVersion = strings.TrimPrefix(entry, "go ")
+					if goVersion, ok := strings.CutPrefix(entry, "go "); ok {
+						meta.GoVersion = goVersion
 						rawGoVersion.Store(mod, meta.GoVersion)
 					}
 					// All other tokens are reserved for future use.

src/cmd/go/internal/test/genflags.go

@@ -68,10 +68,11 @@ func testFlags() []string {
 
 	var names []string
 	flag.VisitAll(func(f *flag.Flag) {
-		if !strings.HasPrefix(f.Name, "test.") {
+		var name string
+		var found bool
+		if name, found = strings.CutPrefix(f.Name, "test."); !found {
 			return
 		}
-		name := strings.TrimPrefix(f.Name, "test.")
 
 		switch name {
 		case "testlogfile", "paniconexit0", "fuzzcachedir", "fuzzworker":

src/cmd/go/internal/work/action.go

@@ -372,8 +372,8 @@ func readpkglist(shlibpath string) (pkgs []*load.Package) {
 		scanner := bufio.NewScanner(bytes.NewBuffer(data))
 		for scanner.Scan() {
 			t := scanner.Text()
-			if strings.HasPrefix(t, "pkgpath ") {
-				t = strings.TrimPrefix(t, "pkgpath ")
+			var found bool
+			if t, found = strings.CutPrefix(t, "pkgpath "); found {
 				t = strings.TrimSuffix(t, ";")
 				pkgs = append(pkgs, load.LoadImportWithFlags(t, base.Cwd(), nil, &stk, nil, 0))
 			}

src/cmd/go/script_test.go

@@ -448,8 +448,7 @@ Script:
 					}).(bool)
 					break
 				}
-				if strings.HasPrefix(cond.tag, "GODEBUG:") {
-					value := strings.TrimPrefix(cond.tag, "GODEBUG:")
+				if value, found := strings.CutPrefix(cond.tag, "GODEBUG:"); found {
 					parts := strings.Split(os.Getenv("GODEBUG"), ",")
 					for _, p := range parts {
 						if strings.TrimSpace(p) == value {
@@ -459,8 +458,7 @@ Script:
 					}
 					break
 				}
-				if strings.HasPrefix(cond.tag, "buildmode:") {
-					value := strings.TrimPrefix(cond.tag, "buildmode:")
+				if value, found := strings.CutPrefix(cond.tag, "buildmode:"); found {
 					ok = sys.BuildModeSupported(runtime.Compiler, value, runtime.GOOS, runtime.GOARCH)
 					break
 				}