Add backport job

Runner/Jobs/BackportJob.cs

@@ -0,0 +1,74 @@
+using System.Net.Http.Headers;
+
+namespace Runner.Jobs;
+
+internal sealed class BackportJob : JobBase
+{
+    public BackportJob(HttpClient client, Dictionary<string, string> metadata) : base(client, metadata) { }
+
+    protected override async Task RunJobCoreAsync()
+    {
+        string pushToken = Metadata["MihuBotPushToken"];
+
+        string baseRepo = Metadata["BackportJob_BaseRepo"];
+        string forkRepo = Metadata["BackportJob_ForkRepo"];
+        string targetBranch = Metadata["BackportJob_TargetBranch"];
+        string newBranch = Metadata["BackportJob_NewBranch"];
+        string patchUrl = Metadata["BackportJob_PatchUrl"];
+        string title = Metadata["BackportJob_Title"];
+
+        File.WriteAllBytes("changes.patch", await HttpClient.GetByteArrayAsync(patchUrl));
+
+        await RunBatchScriptAsync("backport.bat",
+            $$"""
+            git config --system core.longpaths true
+            git clone --progress https://github.com/{{baseRepo}} repo
+            cd repo
+            git log -1
+            git config --global user.email [email protected]
+            git config --global user.name MihuBot
+            git remote add fork https://MihuBot:{{pushToken}}@github.com/{{forkRepo}}.git
+            git checkout {{targetBranch}}
+            git switch -c {{newBranch}}
+            git am --3way --empty=keep --ignore-whitespace --keep-non-patch ../changes.patch
+            git push --set-upstream fork HEAD:{{newBranch}}
+            """,
+            line => line.Replace(pushToken, "<REDACTED>", StringComparison.OrdinalIgnoreCase));
+
+        await CreatePullRequestAsync(pushToken, baseRepo, targetBranch, forkRepo, newBranch, title, body: string.Empty, maintainerCanModify: true);
+    }
+
+    private async Task<int> RunBatchScriptAsync(string name, string script, Func<string, string>? processLogs = null)
+    {
+        File.WriteAllText(name, script);
+        return await RunProcessAsync(name, string.Empty, processLogs: processLogs);
+    }
+
+    private async Task CreatePullRequestAsync(string token, string baseRepo, string baseRef, string headRepo, string head, string title, string body, bool maintainerCanModify)
+    {
+        var request = new HttpRequestMessage(HttpMethod.Post, $"https://api.github.com/repos/{baseRepo}/pulls");
+
+        request.Headers.Accept.ParseAdd("application/vnd.github+json");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+        request.Headers.Add("X-GitHub-Api-Version", "2022-11-28");
+
+        request.Content = JsonContent.Create(new
+        {
+            Title = title,
+            Head = head,
+            HeadRepo = headRepo,
+            Base = baseRef,
+            Body = body,
+            MaintainerCanModify = maintainerCanModify
+        }, options: new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
+        });
+
+        using HttpResponseMessage response = await HttpClient.SendAsync(request, JobTimeout);
+
+        await UploadTextArtifactAsync("GithubResponse.json", await response.Content.ReadAsStringAsync(JobTimeout));
+
+        response.EnsureSuccessStatusCode();
+    }
+}

Runner/Program.cs

@@ -75,6 +75,7 @@ args[0] is string eventPath &&
         nameof(RebaseJob) => new RebaseJob(client, metadata),
         nameof(BenchmarkLibrariesJob) => new BenchmarkLibrariesJob(client, metadata),
         nameof(RegexDiffJob) => new RegexDiffJob(client, metadata),
+        nameof(BackportJob) => new BackportJob(client, metadata),
         var type => throw new NotSupportedException(type),
     };