Provide button to delete merged pull request (#441)

* provide button to delete merged pull request

* golint fix

routers/repo/branch.go

@@ -5,6 +5,7 @@
 package repo
 
 import (
+	"code.gitea.io/git"
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/context"
 )
@@ -30,3 +31,21 @@ func Branches(ctx *context.Context) {
 	ctx.Data["Branches"] = brs
 	ctx.HTML(200, tplBranch)
 }
+
+// DeleteBranchPost responses for delete merged branch
+func DeleteBranchPost(ctx *context.Context) {
+	branchName := ctx.Params(":name")
+
+	if err := ctx.Repo.GitRepo.DeleteBranch(branchName, git.DeleteBranchOptions{
+		Force: false,
+	}); err != nil {
+		ctx.Handle(500, "DeleteBranch", err)
+		return
+	}
+
+	redirectTo := ctx.Query("redirect_to")
+	if len(redirectTo) == 0 {
+		redirectTo = ctx.Repo.RepoLink
+	}
+	ctx.Redirect(redirectTo)
+}

routers/repo/issue.go

@@ -661,6 +661,15 @@ func ViewIssue(ctx *context.Context) {
 		}
 	}
 
+	if issue.IsPull {
+		pull := issue.PullRequest
+		ctx.Data["IsPullBranchDeletable"] = ctx.Repo.IsWriter() && ctx.Repo.GitRepo.IsBranchExist(pull.HeadBranch)
+
+		deleteBranchURL := ctx.Repo.RepoLink + "/branches/" + pull.HeadBranch + "/delete"
+		queryParams := "?redirect_to=" + ctx.Data["Link"].(string)
+		ctx.Data["DeleteBranchLink"] = deleteBranchURL + queryParams
+	}
+
 	ctx.Data["Participants"] = participants
 	ctx.Data["NumParticipants"] = len(participants)
 	ctx.Data["Issue"] = issue