[PATCH 7/7] fast-forward: add help about merge vs. rebase
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git@vger.kernel.org
Cc
Alex Henrie
Ævar Arnfjörð Bjarmason
Randall S . Becker
Nguyễn Thái Ngọc Duy
Denton Liu
Elijah Newren
Junio C Hamano
Felipe Contreras
From
Felipe Contreras
See Also
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Date
2021-07-22 00:08:54 UTC
Now that we have a locus for merge versus rebase documentation, we can
refer to it on the diverging advice.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
---
 Documentation/git-fast-forward.txt | 48 ++++++++++++++++++++++++++++++
 advice.c                           |  4 ++-
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-fast-forward.txt b/Documentation/git-fast-forward.txt
index 38c920964f..1989fdec4a 100644
--- a/Documentation/git-fast-forward.txt
+++ b/Documentation/git-fast-forward.txt
@@ -50,6 +50,54 @@ synchronize the two branches.
 
 THIS COMMAND IS EXPERIMENTAL. THE BEHAVIOUR MAY CHANGE.
 
+MERGE OR REBASE
+---------------
+
+The decision to whether merge or rebase depends on the situation and the
+project. Traditionally git has prefered merge over rebase, but that creates a
+new commit, and that's frowned up on some projects, so you can't just simply
+choose to merge blindly.
+
+------------
+    D---C---B---A origin/master
+	 \
+	  X---Y master
+------------
+
+The nature of distributed version control systems make this divergence
+unavoidable; you must decide how to synchronize this divergence.
+
+Should you choose to merge, the two heads (master and origin/master) will be joined
+together in a new commit:
+
+------------
+	  origin/master
+		|
+		v
+    D---C---B---A---M master
+	 \	   /
+	  X---Y---+
+------------
+
+This new commit is called a "merge commit" and has two parents (A and Y).
+
+Rebasing on the other hand rewrites the history:
+
+------------
+	  origin/master
+		|
+		v
+    D---C---B---A---X'---Y' master
+------------
+
+The commits that diverged (X and Y) are rewritten as if they were created on top
+of the new base (A). This creates a linear history, which is cleaner, but some
+people prefer to preserve the original hsitory.
+
+In both cases it's likely you would have to resolve conflicts, the difference is
+that in a merge you would have to do it all at once in one commit, while with a
+rebase you would have to do it on every rewritten commit.
+
 SEE ALSO
 --------
 linkgit:git-merge[1], linkgit:git-rebase[1]
diff --git a/advice.c b/advice.c
index 60de7fbc4e..7f422b05d3 100644
--- a/advice.c
+++ b/advice.c
@@ -337,5 +337,7 @@ void diverging_advice(void)
 		"\n"
 		"or:\n"
 		"\n"
-		"\tgit rebase\n"));
+		"\tgit rebase\n"
+		"\n"
+		"For more information check \"git help fast-forward\".\n"));
 }
-- 
2.32.0.40.gb9b36f9b52