Add force flag to server redirects config

Fixes gohugoio#7778

commands/server.go

@@ -378,15 +378,33 @@ func (f *fileServer) createEndpoint(i int) (*http.ServeMux, string, string, erro
 			if redirect := f.c.serverConfig.MatchRedirect(requestURI); !redirect.IsZero() {
 				// This matches Netlify's behaviour and is needed for SPA behaviour.
 				// See https://docs.netlify.com/routing/redirects/rewrites-proxies/
-				if redirect.Status == 200 {
-					if r2 := f.rewriteRequest(r, strings.TrimPrefix(redirect.To, u.Path)); r2 != nil {
-						requestURI = redirect.To
-						r = r2
+				if !redirect.Force {
+					path := filepath.Clean(strings.TrimPrefix(requestURI, u.Path))
+					fi, err := f.c.hugo().BaseFs.PublishFs.Stat(path)
+					if err == nil {
+						if fi.IsDir() {
+							// There will be overlapping directories, so we
+							// need to check for a file.
+							_, err = f.c.hugo().BaseFs.PublishFs.Stat(filepath.Join(path, "index.html"))
+							doRedirect = err != nil
+						} else {
+							doRedirect = false
+						}
+
+					}
+				}
+
+				if doRedirect {
+					if redirect.Status == 200 {
+						if r2 := f.rewriteRequest(r, strings.TrimPrefix(redirect.To, u.Path)); r2 != nil {
+							requestURI = redirect.To
+							r = r2
+						}
+					} else {
+						w.Header().Set("Content-Type", "")
+						http.Redirect(w, r, redirect.To, redirect.Status)
+						return
 					}
-				} else {
-					w.Header().Set("Content-Type", "")
-					http.Redirect(w, r, redirect.To, redirect.Status)
-					return
 				}
 
 			}
@@ -416,7 +434,6 @@ func (f *fileServer) createEndpoint(i int) (*http.ServeMux, string, string, erro
 
 	fileserver := decorate(http.FileServer(fs))
 	mu := http.NewServeMux()
-
 	if u.Path == "" || u.Path == "/" {
 		mu.Handle("/", fileserver)
 	} else {

config/commonConfig.go

@@ -184,6 +184,7 @@ type Redirect struct {
 	From   string
 	To     string
 	Status int
+	Force  bool
 }
 
 func (r Redirect) IsZero() bool {

docs/content/en/getting-started/configuration.md

@@ -360,10 +360,10 @@ Note that a `status` code of 200 will trigger a [URL rewrite](https://docs.netli
 from = "/myspa/**"
 to = "/myspa/"
 status = 200
+force = false
 {{< /code-toggle >}}
 
-
-
+{{< new-in "0.76.0" >}} Setting `force=true` will make a redirect even if there is existing content in the path. Note that before Hugo 0.76  `force` was the default behaviour, but this is inline with how Netlify does it.
 
 ## Configure Title Case