From 236890b58b8255d8d540b5cbd326228489bd0363 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Fri, 8 Jun 2018 23:31:02 +0100
Subject: [PATCH] Commentary: explain why pseudomerges are the way round they
 are

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 dgit          | 2 ++
 git-debrebase | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/dgit b/dgit
index 2a581f38..dc423592 100755
--- a/dgit
+++ b/dgit
@@ -3888,6 +3888,8 @@ sub pseudomerge_make_commit ($$$$ $$) {
 	: !length  $overwrite_version ? " --overwrite"
 	: " --overwrite=".$overwrite_version;
 
+    # Contributing parent is the first parent - that makes
+    # git rev-list --first-parent DTRT.
     my $pmf = dgit_privdir()."/pseudomerge";
     open MC, ">", $pmf or die "$pmf $!";
     print MC <<END or die $!;
diff --git a/git-debrebase b/git-debrebase
index ad501d8a..f6d379ac 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -1086,6 +1086,8 @@ sub stitch ($$$$$) {
 	}
     }
     fresh_workarea();
+    # We make pseudomerges with L as the contributing parent.
+    # This makes git rev-list --first-parent work properly.
     my $new_head = make_commit [ $old_head, $ffq_prev ], [
 	'Declare fast forward / record previous work',
         "[git-debrebase pseudomerge: $prose]",
-- 
2.30.2