Fix a performance regression in the built-in rebase #1983
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This is what the legacy (scripted) rebase does in `move_to_original_branch`, and we will need this functionality in the next commit. Signed-off-by: Johannes Schindelin <[email protected]>
In the scripted version, we call `move_to_original_branch`, which updates `HEAD` to point to the original branch again, after updating that branch to point at the current commit. This does not require any worktree update. In the built-in version, we tried to reuse the `reset_head()` function, which however does try to update the worktree. Of course, as there are no changes, no actual worktree updates are performed. However, with an insanely large repository, even just looking whether we need to write anything takes a noticeable time. So let's avoid that in the built-in version, too. Signed-off-by: Johannes Schindelin <[email protected]>
derrickstolee
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Dec 13, 2018
dscho
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Dec 15, 2018
…f-fix Fix a performance regression in the built-in rebase
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In the VFSforGit project, it was detected that the patches to call the
--ambackend directly (i.e thebuiltin-rebase--amtopic branch) introduced a performance regression.The root cause was that we translated the
move_to_original_branchto C by using thereset_head()function which always updated the worktree.But in the case of
move_to_original_branch, we want to update the original branch to point at the current revision, and not change the worktree at all.To work around that performance issue, let's teach
reset_head()to update only the refs.