Make URL scheme unambiguous (#2408)

* Make URL scheme unambiguous

Redirect old routes to new routes

* Fix redirects to new URL scheme, and update template

* Fix branches/_new endpoints, and update integration test

modules/context/repo.go

@@ -14,6 +14,7 @@ import (
 	"code.gitea.io/git"
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/cache"
+	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/Unknwon/com"
@@ -117,6 +118,20 @@ func (r *Repository) GetCommitsCount() (int64, error) {
 	})
 }
 
+// BranchNameSubURL sub-URL for the BranchName field
+func (r *Repository) BranchNameSubURL() string {
+	switch {
+	case r.IsViewBranch:
+		return "branch/" + r.BranchName
+	case r.IsViewTag:
+		return "tag/" + r.BranchName
+	case r.IsViewCommit:
+		return "commit/" + r.BranchName
+	}
+	log.Error(4, "Unknown view type for repo: %v", r)
+	return ""
+}
+
 // GetEditorconfig returns the .editorconfig definition if found in the
 // HEAD of the default repo branch.
 func (r *Repository) GetEditorconfig() (*editorconfig.Editorconfig, error) {
@@ -444,8 +459,81 @@ func RepoAssignment() macaron.Handler {
 	}
 }
 
-// RepoRef handles repository reference name including those contain `/`.
+// RepoRefType type of repo reference
+type RepoRefType int
+
+const (
+	// RepoRefLegacy unknown type, make educated guess and redirect.
+	// for backward compatibility with previous URL scheme
+	RepoRefLegacy RepoRefType = iota
+	// RepoRefBranch branch
+	RepoRefBranch
+	// RepoRefTag tag
+	RepoRefTag
+	// RepoRefCommit commit
+	RepoRefCommit
+)
+
+// RepoRef handles repository reference names when the ref name is not
+// explicitly given
 func RepoRef() macaron.Handler {
+	// since no ref name is explicitly specified, ok to just use branch
+	return RepoRefByType(RepoRefBranch)
+}
+
+func getRefNameFromPath(ctx *Context, path string, isExist func(string) bool) string {
+	refName := ""
+	parts := strings.Split(path, "/")
+	for i, part := range parts {
+		refName = strings.TrimPrefix(refName+"/"+part, "/")
+		if isExist(refName) {
+			ctx.Repo.TreePath = strings.Join(parts[i+1:], "/")
+			return refName
+		}
+	}
+	return ""
+}
+
+func getRefName(ctx *Context, pathType RepoRefType) string {
+	path := ctx.Params("*")
+	switch pathType {
+	case RepoRefLegacy:
+		if refName := getRefName(ctx, RepoRefBranch); len(refName) > 0 {
+			return refName
+		}
+		if refName := getRefName(ctx, RepoRefTag); len(refName) > 0 {
+			return refName
+		}
+		return getRefName(ctx, RepoRefCommit)
+	case RepoRefBranch:
+		return getRefNameFromPath(ctx, path, ctx.Repo.GitRepo.IsBranchExist)
+	case RepoRefTag:
+		return getRefNameFromPath(ctx, path, ctx.Repo.GitRepo.IsTagExist)
+	case RepoRefCommit:
+		parts := strings.Split(path, "/")
+		if len(parts) > 0 && len(parts[0]) == 40 {
+			ctx.Repo.TreePath = strings.Join(parts[1:], "/")
+			return parts[0]
+		}
+	default:
+		log.Error(4, "Unrecognized path type: %v", path)
+	}
+	return ""
+}
+
+// URL to redirect to for deprecated URL scheme
+func repoRefRedirect(ctx *Context) string {
+	urlPath := ctx.Req.URL.String()
+	idx := strings.LastIndex(urlPath, ctx.Params("*"))
+	if idx < 0 {
+		idx = len(urlPath)
+	}
+	return path.Join(urlPath[:idx], ctx.Repo.BranchNameSubURL())
+}
+
+// RepoRefByType handles repository reference name for a specific type
+// of repository reference
+func RepoRefByType(refType RepoRefType) macaron.Handler {
 	return func(ctx *Context) {
 		// Empty repository does not have reference information.
 		if ctx.Repo.Repository.IsBare {
@@ -470,6 +558,7 @@ func RepoRef() macaron.Handler {
 		// Get default branch.
 		if len(ctx.Params("*")) == 0 {
 			refName = ctx.Repo.Repository.DefaultBranch
+			ctx.Repo.BranchName = refName
 			if !ctx.Repo.GitRepo.IsBranchExist(refName) {
 				brs, err := ctx.Repo.GitRepo.GetBranches()
 				if err != nil {
@@ -492,25 +581,8 @@ func RepoRef() macaron.Handler {
 			ctx.Repo.IsViewBranch = true
 
 		} else {
-			hasMatched := false
-			parts := strings.Split(ctx.Params("*"), "/")
-			for i, part := range parts {
-				refName = strings.TrimPrefix(refName+"/"+part, "/")
-
-				if ctx.Repo.GitRepo.IsBranchExist(refName) ||
-					ctx.Repo.GitRepo.IsTagExist(refName) {
-					if i < len(parts)-1 {
-						ctx.Repo.TreePath = strings.Join(parts[i+1:], "/")
-					}
-					hasMatched = true
-					break
-				}
-			}
-			if !hasMatched && len(parts[0]) == 40 {
-				refName = parts[0]
-				ctx.Repo.TreePath = strings.Join(parts[1:], "/")
-			}
-
+			refName = getRefName(ctx, refType)
+			ctx.Repo.BranchName = refName
 			if ctx.Repo.GitRepo.IsBranchExist(refName) {
 				ctx.Repo.IsViewBranch = true
 
@@ -542,10 +614,16 @@ func RepoRef() macaron.Handler {
 				ctx.Handle(404, "RepoRef invalid repo", fmt.Errorf("branch or tag not exist: %s", refName))
 				return
 			}
+
+			if refType == RepoRefLegacy {
+				// redirect from old URL scheme to new URL scheme
+				ctx.Redirect(repoRefRedirect(ctx))
+				return
+			}
 		}
 
-		ctx.Repo.BranchName = refName
 		ctx.Data["BranchName"] = ctx.Repo.BranchName
+		ctx.Data["BranchNameSubURL"] = ctx.Repo.BranchNameSubURL()
 		ctx.Data["CommitID"] = ctx.Repo.CommitID
 		ctx.Data["TreePath"] = ctx.Repo.TreePath
 		ctx.Data["IsViewBranch"] = ctx.Repo.IsViewBranch