Clean up various use of escape/unescape functions for URL generation (#6334)

* Use PathUnescape instead of QueryUnescape when working with branch names

Currently branch names with a '+' fail in certain situations because
QueryUnescape replaces the + character with a blank space.

Using PathUnescape should be better since it is defined as:

// PathUnescape is identical to QueryUnescape except that it does not
// unescape '+' to ' ' (space).

Fixes #6333

* Change error to match new function name

* Add new util function PathEscapeSegments

This function simply runs PathEscape on each segment of a path without
touching the forward slash itself. We want to use this instead of
PathEscape/QueryEscape in most cases because a forward slash is a valid name for a
branch etc... and we don't want that escaped in a URL.

Putting this in new file url.go and also moving a couple similar
functions into that file as well.

* Use EscapePathSegments where appropriate

Replace various uses of EscapePath/EscapeQuery with new
EscapePathSegments. Also remove uncessary uses of various
escape/unescape functions when the text had already been escaped or was
not escaped.

* Reformat comment to make drone build happy

* Remove no longer used url library

* Requested code changes

3 files changed, 6 insertions, 7 deletions

diff --git a/modules/context/auth.go b/modules/context/auth.go
index 9d9bd81c75..ca897de6ed 100644
--- a/modules/context/auth.go
+++ b/modules/context/auth.go
@@ -5,8 +5,6 @@
 package context
 
 import (
-	"net/url"
-
 	"code.gitea.io/gitea/modules/auth"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -48,7 +46,7 @@ func Toggle(options *ToggleOptions) macaron.Handler {
 				if ctx.Req.URL.Path != "/user/settings/change_password" {
 					ctx.Data["Title"] = ctx.Tr("auth.must_change_password")
 					ctx.Data["ChangePasscodeLink"] = setting.AppSubURL + "/user/change_password"
-					ctx.SetCookie("redirect_to", url.QueryEscape(setting.AppSubURL+ctx.Req.RequestURI), 0, setting.AppSubURL)
+					ctx.SetCookie("redirect_to", setting.AppSubURL+ctx.Req.RequestURI, 0, setting.AppSubURL)
 					ctx.Redirect(setting.AppSubURL + "/user/settings/change_password")
 					return
 				}
@@ -82,7 +80,7 @@ func Toggle(options *ToggleOptions) macaron.Handler {
 					return
 				}
 
-				ctx.SetCookie("redirect_to", url.QueryEscape(setting.AppSubURL+ctx.Req.RequestURI), 0, setting.AppSubURL)
+				ctx.SetCookie("redirect_to", setting.AppSubURL+ctx.Req.RequestURI, 0, setting.AppSubURL)
 				ctx.Redirect(setting.AppSubURL + "/user/login")
 				return
 			} else if !ctx.User.IsActive && setting.Service.RegisterEmailConfirm {
@@ -95,7 +93,7 @@ func Toggle(options *ToggleOptions) macaron.Handler {
 		// Redirect to log in page if auto-signin info is provided and has not signed in.
 		if !options.SignOutRequired && !ctx.IsSigned && !auth.IsAPIPath(ctx.Req.URL.Path) &&
 			len(ctx.GetCookie(setting.CookieUserName)) > 0 {
-			ctx.SetCookie("redirect_to", url.QueryEscape(setting.AppSubURL+ctx.Req.RequestURI), 0, setting.AppSubURL)
+			ctx.SetCookie("redirect_to", setting.AppSubURL+ctx.Req.RequestURI, 0, setting.AppSubURL)
 			ctx.Redirect(setting.AppSubURL + "/user/login")
 			return
 		}
diff --git a/modules/context/context.go b/modules/context/context.go
index 5d4a2cad54..5c7254de22 100644
--- a/modules/context/context.go
+++ b/modules/context/context.go
@@ -19,6 +19,7 @@ import (
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 	"github.com/Unknwon/com"
 	"github.com/go-macaron/cache"
 	"github.com/go-macaron/csrf"
@@ -211,7 +212,7 @@ func Contexter() macaron.Handler {
 			if err == nil && len(repo.DefaultBranch) > 0 {
 				branchName = repo.DefaultBranch
 			}
-			prefix := setting.AppURL + path.Join(url.QueryEscape(ownerName), url.QueryEscape(repoName), "src", "branch", branchName)
+			prefix := setting.AppURL + path.Join(url.PathEscape(ownerName), url.PathEscape(repoName), "src", "branch", util.PathEscapeSegments(branchName))
 			c.Header().Set("Content-Type", "text/html")
 			c.WriteHeader(http.StatusOK)
 			c.Write([]byte(com.Expand(`<!doctype html>
diff --git a/modules/context/repo.go b/modules/context/repo.go
index 8f2622fa82..e0ee802f7d 100644
--- a/modules/context/repo.go
+++ b/modules/context/repo.go
@@ -172,7 +172,7 @@ func RetrieveBaseRepo(ctx *Context, repo *models.Repository) {
 
 // ComposeGoGetImport returns go-get-import meta content.
 func ComposeGoGetImport(owner, repo string) string {
-	return path.Join(setting.Domain, setting.AppSubURL, url.QueryEscape(owner), url.QueryEscape(repo))
+	return path.Join(setting.Domain, setting.AppSubURL, url.PathEscape(owner), url.PathEscape(repo))
 }
 
 // EarlyResponseForGoGetMeta responses appropriate go-get meta with status 200