refactor: http request binding (#38971)

Better than before, still not good enough (more work can be done in the
future)

And add the missing error handling in the PrivateContext "bind"
middleware.

By the way, picked some "TrimSpace" changes from "fix: trim whitespace
from SMTP address and port - #38934" (fix #38926)

modules/issue/template/template.go

@@ -11,13 +11,21 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+	"sync"
 
 	"gitea.dev/modules/container"
 	api "gitea.dev/modules/structs"
-
-	"gitea.com/go-chi/binding"
 )
 
+var globalVars = sync.OnceValue(func() (ret struct {
+	nonAlphaDashPattern, minQuotesRegex *regexp.Regexp
+},
+) {
+	ret.nonAlphaDashPattern = regexp.MustCompile(`[^\w-]`)
+	ret.minQuotesRegex = regexp.MustCompilePOSIX("^`{3,}")
+	return ret
+})
+
 // Validate checks whether an IssueTemplate is considered valid, and returns the first error
 func Validate(template *api.IssueTemplate) error {
 	if err := validateMetadata(template); err != nil {
@@ -150,7 +158,7 @@ func validateID(field *api.IssueFormField, idx int, ids container.Set[string]) e
 		// If the ID is empty in yaml, template.Unmarshal will auto autofill it, so it cannot be empty
 		return position.Errorf("'id' is required")
 	}
-	if binding.AlphaDashPattern.MatchString(field.ID) {
+	if globalVars().nonAlphaDashPattern.MatchString(field.ID) {
 		return position.Errorf("'id' should contain only alphanumeric, '-' and '_'")
 	}
 	if !ids.Add(field.ID) {
@@ -471,13 +479,11 @@ func (o *valuedOption) VisibleInContent() bool {
 	return true
 }
 
-var minQuotesRegex = regexp.MustCompilePOSIX("^`{3,}")
-
 // minQuotes return 3 or more back-quotes.
 // If n back-quotes exists, use n+1 back-quotes to quote.
 func minQuotes(value string) string {
 	ret := "```"
-	for _, v := range minQuotesRegex.FindAllString(value, -1) {
+	for _, v := range globalVars().minQuotesRegex.FindAllString(value, -1) {
 		if len(v) >= len(ret) {
 			ret = v + "`"
 		}