Also display "recently pushed branch" alert on PR view (#35001)

This commit adds the "You recently pushed to branch X" alert also to PR
overview, as opposed to only the repository's home page.

GitHub also shows this alert on the PR list, as well as the home page.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

routers/web/repo/common_recentbranches.go

@@ -0,0 +1,73 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package repo
+
+import (
+	git_model "code.gitea.io/gitea/models/git"
+	access_model "code.gitea.io/gitea/models/perm/access"
+	unit_model "code.gitea.io/gitea/models/unit"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/services/context"
+	repo_service "code.gitea.io/gitea/services/repository"
+)
+
+type RecentBranchesPromptDataStruct struct {
+	RecentlyPushedNewBranches []*git_model.RecentlyPushedNewBranch
+}
+
+func prepareRecentlyPushedNewBranches(ctx *context.Context) {
+	if ctx.Doer == nil {
+		return
+	}
+	if err := ctx.Repo.Repository.GetBaseRepo(ctx); err != nil {
+		log.Error("GetBaseRepo: %v", err)
+		return
+	}
+
+	opts := git_model.FindRecentlyPushedNewBranchesOptions{
+		Repo:     ctx.Repo.Repository,
+		BaseRepo: ctx.Repo.Repository,
+	}
+	if ctx.Repo.Repository.IsFork {
+		opts.BaseRepo = ctx.Repo.Repository.BaseRepo
+	}
+
+	baseRepoPerm, err := access_model.GetUserRepoPermission(ctx, opts.BaseRepo, ctx.Doer)
+	if err != nil {
+		log.Error("GetUserRepoPermission: %v", err)
+		return
+	}
+	if !opts.Repo.CanContentChange() || !opts.BaseRepo.CanContentChange() {
+		return
+	}
+	if !opts.BaseRepo.UnitEnabled(ctx, unit_model.TypePullRequests) || !baseRepoPerm.CanRead(unit_model.TypePullRequests) {
+		return
+	}
+
+	var finalBranches []*git_model.RecentlyPushedNewBranch
+	branches, err := git_model.FindRecentlyPushedNewBranches(ctx, ctx.Doer, opts)
+	if err != nil {
+		log.Error("FindRecentlyPushedNewBranches failed: %v", err)
+		return
+	}
+
+	for _, branch := range branches {
+		divergingInfo, err := repo_service.GetBranchDivergingInfo(ctx,
+			branch.BranchRepo, branch.BranchName, // "base" repo for diverging info
+			opts.BaseRepo, opts.BaseRepo.DefaultBranch, // "head" repo for diverging info
+		)
+		if err != nil {
+			log.Error("GetBranchDivergingInfo failed: %v", err)
+			continue
+		}
+		branchRepoHasNewCommits := divergingInfo.BaseHasNewCommits
+		baseRepoCommitsBehind := divergingInfo.HeadCommitsBehind
+		if branchRepoHasNewCommits || baseRepoCommitsBehind > 0 {
+			finalBranches = append(finalBranches, branch)
+		}
+	}
+	if len(finalBranches) > 0 {
+		ctx.Data["RecentBranchesPromptData"] = RecentBranchesPromptDataStruct{finalBranches}
+	}
+}