Fix sync fork for consistency (#33147)

Fixes #33145

An integration test could be added.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

2 files changed, 81 insertions, 3 deletions

diff --git a/templates/repo/code/upstream_diverging_info.tmpl b/templates/repo/code/upstream_diverging_info.tmpl
index 51402598f9..bdcd99a7f7 100644
--- a/templates/repo/code/upstream_diverging_info.tmpl
+++ b/templates/repo/code/upstream_diverging_info.tmpl
@@ -1,8 +1,8 @@
-{{if and .UpstreamDivergingInfo (or .UpstreamDivergingInfo.BaseIsNewer .UpstreamDivergingInfo.CommitsBehind)}}
+{{if and .UpstreamDivergingInfo (or .UpstreamDivergingInfo.BaseHasNewCommits .UpstreamDivergingInfo.CommitsBehind)}}
 <div class="ui message flex-text-block">
 	<div class="tw-flex-1">
-		{{$upstreamLink := printf "%s/src/branch/%s" .Repository.BaseRepo.Link (.BranchName|PathEscapeSegments)}}
-		{{$upstreamHtml := HTMLFormat `<a href="%s">%s:%s</a>` $upstreamLink .Repository.BaseRepo.FullName .BranchName}}
+		{{$upstreamLink := printf "%s/src/branch/%s" .Repository.BaseRepo.Link (.Repository.BaseRepo.DefaultBranch|PathEscapeSegments)}}
+		{{$upstreamHtml := HTMLFormat `<a href="%s">%s:%s</a>` $upstreamLink .Repository.BaseRepo.FullName .Repository.BaseRepo.DefaultBranch}}
 		{{if .UpstreamDivergingInfo.CommitsBehind}}
 			{{ctx.Locale.TrN .UpstreamDivergingInfo.CommitsBehind "repo.pulls.upstream_diverging_prompt_behind_1" "repo.pulls.upstream_diverging_prompt_behind_n" .UpstreamDivergingInfo.CommitsBehind $upstreamHtml}}
 		{{else}}
diff --git a/templates/swagger/v1_json.tmpl b/templates/swagger/v1_json.tmpl
index 82a301da2f..fb37d45ce8 100644
--- a/templates/swagger/v1_json.tmpl
+++ b/templates/swagger/v1_json.tmpl
@@ -10867,6 +10867,52 @@
         }
       }
     },
+    "/repos/{owner}/{repo}/merge-upstream": {
+      "post": {
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "repository"
+        ],
+        "summary": "Merge a branch from upstream",
+        "operationId": "repoMergeUpstream",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "owner of the repo",
+            "name": "owner",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "name of the repo",
+            "name": "repo",
+            "in": "path",
+            "required": true
+          },
+          {
+            "name": "body",
+            "in": "body",
+            "schema": {
+              "$ref": "#/definitions/MergeUpstreamRequest"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "$ref": "#/responses/MergeUpstreamResponse"
+          },
+          "400": {
+            "$ref": "#/responses/error"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
+          }
+        }
+      }
+    },
     "/repos/{owner}/{repo}/milestones": {
       "get": {
         "produces": [
@@ -22827,6 +22873,26 @@
       "x-go-name": "MergePullRequestForm",
       "x-go-package": "code.gitea.io/gitea/services/forms"
     },
+    "MergeUpstreamRequest": {
+      "type": "object",
+      "properties": {
+        "branch": {
+          "type": "string",
+          "x-go-name": "Branch"
+        }
+      },
+      "x-go-package": "code.gitea.io/gitea/modules/structs"
+    },
+    "MergeUpstreamResponse": {
+      "type": "object",
+      "properties": {
+        "merge_type": {
+          "type": "string",
+          "x-go-name": "MergeStyle"
+        }
+      },
+      "x-go-package": "code.gitea.io/gitea/modules/structs"
+    },
     "MigrateRepoOptions": {
       "description": "MigrateRepoOptions options for migrating repository's\nthis is used to interact with api v1",
       "type": "object",
@@ -26008,6 +26074,18 @@
         "type": "string"
       }
     },
+    "MergeUpstreamRequest": {
+      "description": "",
+      "schema": {
+        "$ref": "#/definitions/MergeUpstreamRequest"
+      }
+    },
+    "MergeUpstreamResponse": {
+      "description": "",
+      "schema": {
+        "$ref": "#/definitions/MergeUpstreamResponse"
+      }
+    },
     "Milestone": {
       "description": "Milestone",
       "schema": {