[PATCH v2 0/4] Fix ORIG_HEAD behavior of the built-in rebase
- Date: Sun, 03 Mar 2019 09:11:52 -0800 (PST)
- From: "Johannes Schindelin via GitGitGadget" <gitgitgadget@xxxxxxxxx>
- Subject: [PATCH v2 0/4] Fix ORIG_HEAD behavior of the built-in rebase
It was reported by Nazri Ramliy that ORIG_HEAD was set incorrectly again,
this time caused by the shortcut to call git am directly, without detouring
to a Unix shell script.
Patch 2/4 might look like something completely unrelated, but without it,
the update to HEAD might use an incorrect reflog message.
Patch 1/4 is more a "while at it" patch; while looking which code paths
might need to update ORIG_HEAD, I noticed that this reset_head() call did
Changes since v1:
* Reworded the unclear commit message of patch 1/4.
Johannes Schindelin (4):
built-in rebase: no need to check out `onto` twice
built-in rebase: use the correct reflog when switching branches
built-in rebase: demonstrate that ORIG_HEAD is not set correctly
built-in rebase: set ORIG_HEAD just once, before the rebase
builtin/rebase.c | 37 +++++++++++++++++++++----------------
t/t3400-rebase.sh | 8 ++++++++
2 files changed, 29 insertions(+), 16 deletions(-)
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-153/dscho/rebase-am-and-orig-head-v2
Range-diff vs v1:
1: 2d99429387 ! 1: 59c3266ed5 built-in rebase: no need to check out `onto` twice
@@ -4,12 +4,21 @@
In the case that the rebase boils down to a fast-forward, the built-in
rebase reset the working tree twice: once to start the rebase at `onto`,
- then realizing that the original HEAD was an ancestor, `reset_head()`
- was called to update the original ref and to point HEAD back to it.
+ then realizing that the original (pre-rebase) HEAD was an ancestor and
+ we basically already fast-forwarded to the post-rebase HEAD,
+ `reset_head()` was called to update the original ref and to point HEAD
+ back to it.
That second `reset_head()` call does not need to touch the working tree,
- though, as it does not change the actual tip commit. So let's avoid that
- unnecessary work.
+ though, as it does not change the actual tip commit (and therefore the
+ working tree should stay unchanged anyway): only the ref needs to be
+ updated (because the rebase detached the HEAD, and we want to go back to
+ the branch on which the rebase was started).
+ But that second `reset_head()` was called without the flag to leave the
+ working tree alone (the reason: when that call was introduced, that flag
+ was not yet even thought of). Let's avoid that unnecessary work by
+ passing that flag.
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
2: b92d76065d = 2: 67e41c032a built-in rebase: use the correct reflog when switching branches
3: 1bc3cbad26 = 3: 17737998f4 built-in rebase: demonstrate that ORIG_HEAD is not set correctly
4: 1786c172ef = 4: 7891c05f51 built-in rebase: set ORIG_HEAD just once, before the rebase