fix: use url.JoinPath to join url parts

This avoids duplicated or more slashes.

fixes #4759

(cherry picked from commit 46357e7856)

services/pull/merge.go

@@ -7,6 +7,7 @@ package pull
 import (
 	"context"
 	"fmt"
+	"net/url"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -56,7 +57,11 @@ func getMergeMessage(ctx context.Context, baseGitRepo *git.Repository, pr *issue
 		issueReference = "!"
 	}
 
-	reviewedOn := fmt.Sprintf("Reviewed-on: %s/%s", setting.AppURL, pr.Issue.Link())
+	issueURL, err := url.JoinPath(setting.AppURL, pr.Issue.Link())
+	if err != nil {
+		return "", "", err
+	}
+	reviewedOn := fmt.Sprintf("Reviewed-on: %s", issueURL)
 	reviewedBy := pr.GetApprovers(ctx)
 
 	if mergeStyle != "" {

services/pull/pull_test.go

@@ -47,9 +47,10 @@ func TestPullRequest_GetDefaultMergeMessage_InternalTracker(t *testing.T) {
 	require.NoError(t, err)
 	defer gitRepo.Close()
 
-	mergeMessage, _, err := GetDefaultMergeMessage(db.DefaultContext, gitRepo, pr, "")
+	mergeMessage, body, err := GetDefaultMergeMessage(db.DefaultContext, gitRepo, pr, "")
 	require.NoError(t, err)
 	assert.Equal(t, "Merge pull request 'issue3' (#3) from branch2 into master", mergeMessage)
+	assert.Equal(t, "Reviewed-on: https://try.gitea.io/user2/repo1/pulls/3\n", body)
 
 	pr.BaseRepoID = 1
 	pr.HeadRepoID = 2