all: fix printf(var) mistake detected by latest printf checker

For golang/go#69267.

Change-Id: I050c167e2e3ce36541e0d71469fb3f5778f5a882
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/610517
Reviewed-by: Ian Lance Taylor <[email protected]>
kokoro-CI: kokoro <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: timothy-king

cmd/pkgsite/main.go

@@ -106,12 +106,12 @@ func main() {
 	if *useProxy {
 		url := os.Getenv("GOPROXY")
 		if url == "" {
-			die("GOPROXY environment variable is not set")
+			dief("GOPROXY environment variable is not set")
 		}
 		var err error
 		serverCfg.Proxy, err = proxy.New(url, nil)
 		if err != nil {
-			die("connecting to proxy: %s", err)
+			dief("connecting to proxy: %s", err)
 		}
 	}
 
@@ -122,7 +122,7 @@ func main() {
 	ctx := context.Background()
 	server, err := pkgsite.BuildServer(ctx, serverCfg)
 	if err != nil {
-		die(err.Error())
+		dief("%s", err)
 	}
 
 	addr := *httpAddr
@@ -132,7 +132,7 @@ func main() {
 
 	ln, err := net.Listen("tcp", addr)
 	if err != nil {
-		die(err.Error())
+		dief("%s", err)
 	}
 
 	url := "http://" + addr
@@ -150,10 +150,10 @@ func main() {
 	server.Install(router.Handle, nil, nil)
 	mw := timeout.Timeout(54 * time.Second)
 	srv := &http.Server{Addr: addr, Handler: mw(router)}
-	die("%v", srv.Serve(ln))
+	dief("%v", srv.Serve(ln))
 }
 
-func die(format string, args ...any) {
+func dief(format string, args ...any) {
 	fmt.Fprintf(os.Stderr, format, args...)
 	fmt.Fprintln(os.Stderr)
 	os.Exit(1)

internal/frontend/client/client.go

@@ -8,6 +8,7 @@ package client
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -81,7 +82,7 @@ func (c *Client) fetchJSONPage(url string) (_ []byte, err error) {
 	}
 	defer r.Body.Close()
 	if r.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf(r.Status)
+		return nil, errors.New(r.Status)
 	}
 	body, err := io.ReadAll(r.Body)
 	if err != nil {

internal/symbol/generate.go

@@ -289,7 +289,7 @@ func (w *Walker) loadImports(pkgPath string) {
 // except we also check if a field is Embedded. If so, we ignore that field.
 func (w *Walker) emitStructType(name string, typ *types.Struct) {
 	typeStruct := fmt.Sprintf("type %s struct", name)
-	w.emitf(typeStruct)
+	w.emitf("%s", typeStruct)
 	defer w.pushScope(typeStruct)()
 	for i := 0; i < typ.NumFields(); i++ {
 		f := typ.Field(i)
@@ -312,8 +312,8 @@ func (w *Walker) emitStructType(name string, typ *types.Struct) {
 // https://go.googlesource.com/go/+/refs/tags/go1.16.6/src/cmd/api/goapi.go#931,
 // except we don't check for unexported methods.
 func (w *Walker) emitIfaceType(name string, typ *types.Interface) {
-	typeInterface := fmt.Sprintf("type " + name + " interface")
-	w.emitf(typeInterface)
+	typeInterface := fmt.Sprintf("type %s interface", name)
+	w.emitf("%s", typeInterface)
 	pop := w.pushScope(typeInterface)
 
 	var methodNames []string