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From: "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: Elijah Newren <newren@gmail.com>, Patrick Steinhardt <ps@pks.im>,
	Johannes Schindelin <johannes.schindelin@gmx.de>,
	Johannes Schindelin <johannes.schindelin@gmx.de>
Subject: [PATCH/RFC 3/5] history.adoc: describe merge-replay support and its limits
Date: Wed, 06 May 2026 22:43:22 +0000	[thread overview]
Message-ID: <1dfbd26d757e7e610f8ef8058d839f103059b733.1778107405.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.2106.git.1778107405.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx.de>

Replace the blanket "does not (yet) work with histories that contain
merges" caveat now that 2-parent merges are supported via the R/O/N
algorithm. Spell out what works (the user's manual conflict
resolution and any semantic edits inside the merge are preserved
through the replay), what is intentionally out of scope (octopus
merges; symbol-level extrapolation when rewriting parents pulls in
genuinely new content), and what still requires interactive rebase
(merges that would actually conflict on replay).

Assisted-by: Claude Opus 4.7
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 Documentation/git-history.adoc | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/Documentation/git-history.adoc b/Documentation/git-history.adoc
index 24dc907033..56328a7c59 100644
--- a/Documentation/git-history.adoc
+++ b/Documentation/git-history.adoc
@@ -40,13 +40,26 @@ at once.
 LIMITATIONS
 -----------
 
-This command does not (yet) work with histories that contain merges. You
-should use linkgit:git-rebase[1] with the `--rebase-merges` flag instead.
-
-Furthermore, the command does not support operations that can result in merge
-conflicts. This limitation is by design as history rewrites are not intended to
-be stateful operations. The limitation can be lifted once (if) Git learns about
-first-class conflicts.
+This command supports two-parent merge commits in the rewrite path:
+the auto-remerged tree of the original parents, the merge commit
+itself, and the auto-merged tree of the rewritten parents are
+combined so that the user's manual conflict resolution (textual or
+semantic) is preserved through the replay. Octopus merges (more than
+two parents) are not supported and are rejected with an error.
+
+The replay propagates the textual diffs the user actually made in
+the merge commit. It does _not_ extrapolate symbol-level intent: if
+rewriting the parents pulls in genuinely new content (for example, a
+new caller of a function that the merge renamed), that new content
+is _not_ rewritten by the replay and may need a follow-up edit.
+Symbol-aware refactoring is out of scope here, just as it is for
+plain rebase.
+
+The command does not support operations that can result in merge
+conflicts on the replayed merge itself. This limitation is by design
+as history rewrites are not intended to be stateful operations. Use
+linkgit:git-rebase[1] with the `--rebase-merges` flag when the
+rewrite is expected to require interactive conflict resolution.
 
 COMMANDS
 --------
-- 
gitgitgadget


  parent reply	other threads:[~2026-05-06 22:43 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-06 22:43 [PATCH/RFC 0/5] replay: support replaying 2-parent merges Johannes Schindelin via GitGitGadget
2026-05-06 22:43 ` [PATCH/RFC 1/5] " Johannes Schindelin via GitGitGadget
2026-05-08  9:36   ` Phillip Wood
2026-05-08 10:05     ` Phillip Wood
2026-05-06 22:43 ` [PATCH/RFC 2/5] replay: short-circuit merge replay when parent and base trees are unchanged Johannes Schindelin via GitGitGadget
2026-05-06 22:43 ` Johannes Schindelin via GitGitGadget [this message]
2026-05-06 22:43 ` [PATCH/RFC 4/5] test-tool: add a "historian" subcommand for building merge fixtures Johannes Schindelin via GitGitGadget
2026-05-12 10:54   ` Toon Claes
2026-05-06 22:43 ` [PATCH/RFC 5/5] t3454: cover merge-replay scenarios with the historian helper Johannes Schindelin via GitGitGadget
2026-05-07 14:14 ` [PATCH/RFC 0/5] replay: support replaying 2-parent merges D. Ben Knoble
2026-05-07 15:06   ` Johannes Schindelin
2026-05-07 15:39     ` Ben Knoble

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