feature: auto-track remote branch when the remote branch is first time to checkout (#1616)

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/Commands/Branch.cs

@@ -32,12 +32,12 @@ public async Task<bool> RenameAsync(string to)
             return await ExecAsync().ConfigureAwait(false);
         }
 
-        public async Task<bool> SetUpstreamAsync(string upstream)
+        public async Task<bool> SetUpstreamAsync(Models.Branch tracking)
         {
-            if (string.IsNullOrEmpty(upstream))
+            if (tracking == null)
                 Args = $"branch {_name} --unset-upstream";
             else
-                Args = $"branch {_name} -u {upstream}";
+                Args = $"branch {_name} -u {tracking.FriendlyName}";
 
             return await ExecAsync().ConfigureAwait(false);
         }

src/ViewModels/CreateBranch.cs

@@ -192,6 +192,24 @@ public override async Task<bool> Sure()
                     .CreateAsync(_baseOnRevision, _allowOverwrite);
             }
 
+            if (succ && BasedOn is Models.Branch { IsLocal: false } basedOn)
+            {
+                var autoSetUpstream = true;
+                foreach (var b in _repo.Branches)
+                {
+                    if (b.IsLocal && b.Upstream.Equals(basedOn.FullName, StringComparison.Ordinal))
+                    {
+                        autoSetUpstream = false;
+                        break;
+                    }
+                }
+
+                if (autoSetUpstream)
+                    await new Commands.Branch(_repo.FullPath, fixedName)
+                        .Use(log)
+                        .SetUpstreamAsync(basedOn);
+            }
+
             log.Complete();
 
             if (succ && CheckoutAfterCreated)

src/ViewModels/SetUpstream.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Threading.Tasks;
 
 namespace SourceGit.ViewModels
@@ -53,17 +54,24 @@ public SetUpstream(Repository repo, Models.Branch local, List<Models.Branch> rem
         public override async Task<bool> Sure()
         {
             ProgressDescription = "Setting upstream...";
+            Models.Branch upstream = _unset ? null : SelectedRemoteBranch;
 
-            var upstream = (_unset || SelectedRemoteBranch == null) ? string.Empty : SelectedRemoteBranch.FullName;
-            if (upstream == Local.Upstream)
+            if (upstream == null)
+            {
+                if (string.IsNullOrEmpty(Local.Upstream))
+                    return true;
+            }
+            else if (upstream.FullName.Equals(Local.Upstream, StringComparison.Ordinal))
+            {
                 return true;
+            }
 
             var log = _repo.CreateLog("Set Upstream");
             Use(log);
 
             var succ = await new Commands.Branch(_repo.FullPath, Local.Name)
                 .Use(log)
-                .SetUpstreamAsync(upstream.Replace("refs/remotes/", ""));
+                .SetUpstreamAsync(upstream);
 
             log.Complete();
             if (succ)