From 519c0dcc9749382343f8f80487c9c28d1d206b12 Mon Sep 17 00:00:00 2001
From: Philippe Miossec <pmiossec@gmail.com>
Date: Sat, 13 Jul 2019 22:37:02 +0200
Subject: [PATCH] Add support for "--rebase-merges" for newest version of git

now that we recommend v2.22 (#6769) that deprecate "--preserve-merges"

See:
* for option deprection: https://github.com/git/git/commit/fa1b86e45743fd5895c33adcd3769782e608bb40#diff-c7361e406139e8cd3a300b80b8f8cc8dR1220
* for some doc: https://stackoverflow.com/questions/15915430/what-exactly-does-gits-rebase-preserve-merges-do-and-why/50555740#50555740
---
 GitCommands/Git/GitCommandHelpers.cs                    | 2 +-
 GitCommands/Git/GitVersion.cs                           | 3 +++
 UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs | 4 ++--
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/GitCommands/Git/GitCommandHelpers.cs b/GitCommands/Git/GitCommandHelpers.cs
index 4dd478af9b7..8935b81c306 100644
--- a/GitCommands/Git/GitCommandHelpers.cs
+++ b/GitCommands/Git/GitCommandHelpers.cs
@@ -403,7 +403,7 @@ public static ArgumentString RebaseCmd(string branch, bool interactive, bool pre
                 { interactive, "-i" },
                 { interactive && autosquash, "--autosquash" },
                 { interactive && !autosquash, "--no-autosquash" },
-                { preserveMerges, "--preserve-merges" },
+                { preserveMerges, GitVersion.Current.SupportRebaseMerges ? "--rebase-merges" : "--preserve-merges" },
                 { autoStash, "--autostash" },
                 from.QuoteNE(),
                 branch.Quote(),
diff --git a/GitCommands/Git/GitVersion.cs b/GitCommands/Git/GitVersion.cs
index ec9c766a9a8..cf9e2fb04d0 100644
--- a/GitCommands/Git/GitVersion.cs
+++ b/GitCommands/Git/GitVersion.cs
@@ -19,6 +19,7 @@ public class GitVersion : IComparable<GitVersion>
         private static readonly GitVersion v2_11_0 = new GitVersion("2.11.0");
         private static readonly GitVersion v2_15_0 = new GitVersion("2.15.0");
         private static readonly GitVersion v2_15_2 = new GitVersion("2.15.2");
+        private static readonly GitVersion v2_19_0 = new GitVersion("2.19.0");
 
         public static readonly GitVersion LastSupportedVersion = v2_11_0;
         public static readonly GitVersion LastRecommendedVersion = new GitVersion("2.22.0");
@@ -124,6 +125,8 @@ int Get(IReadOnlyList<int> values, int index)
 
         public bool SupportNoOptionalLocks => this >= v2_15_2;
 
+        public bool SupportRebaseMerges => this >= v2_19_0;
+
         public bool IsUnknown => _a == 0 && _b == 0 && _c == 0 && _d == 0;
 
         // Returns true if it's possible to pass given string as command line
diff --git a/UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs b/UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs
index 4be3fa8790c..eddc264ac9b 100644
--- a/UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs
+++ b/UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs
@@ -605,7 +605,7 @@ public void RebaseCmd()
                 "-c rebase.autoSquash=false rebase -i --no-autosquash \"branch\"",
                 GitCommandHelpers.RebaseCmd("branch", interactive: true, preserveMerges: false, autosquash: false, autoStash: false).Arguments);
             Assert.AreEqual(
-                "-c rebase.autoSquash=false rebase --preserve-merges \"branch\"",
+                GitVersion.Current.SupportRebaseMerges ? "-c rebase.autoSquash=false rebase --rebase-merges \"branch\"" : "-c rebase.autoSquash=false rebase --preserve-merges \"branch\"",
                 GitCommandHelpers.RebaseCmd("branch", interactive: false, preserveMerges: true, autosquash: false, autoStash: false).Arguments);
             Assert.AreEqual(
                 "-c rebase.autoSquash=false rebase \"branch\"",
@@ -617,7 +617,7 @@ public void RebaseCmd()
                 "-c rebase.autoSquash=false rebase -i --autosquash \"branch\"",
                 GitCommandHelpers.RebaseCmd("branch", interactive: true, preserveMerges: false, autosquash: true, autoStash: false).Arguments);
             Assert.AreEqual(
-                "-c rebase.autoSquash=false rebase -i --autosquash --preserve-merges --autostash \"branch\"",
+                GitVersion.Current.SupportRebaseMerges ? "-c rebase.autoSquash=false rebase -i --autosquash --rebase-merges --autostash \"branch\"" : "-c rebase.autoSquash=false rebase -i --autosquash --preserve-merges --autostash \"branch\"",
                 GitCommandHelpers.RebaseCmd("branch", interactive: true, preserveMerges: true, autosquash: true, autoStash: true).Arguments);
 
             // TODO quote 'onto'?