Re: [PATCH 0/3] Make orphaned commit checks configurable

[Derrick Stolee <stolee@gmail.com>]

On 11/10/2026 2:11 PM, Wyatt Holden via GitGitGadget wrote:
> Hi there - my name's Wyatt Holden and I'm a Software Engineer at Microsoft
> :) I've been working with Derrick Stolee over the past few weeks on
> optimizing git in the Office mono-repo. We found some issues around slow
> checkouts on mono-repos in an automated environment:

Welcome, Wyatt! (I was prepared for your series.) 
> When leaving a detached HEAD, git checkout and git switch
> call orphaned_commit_warning() to warn about commits that are not reachable
> from any existing ref or the destination HEAD. This requires enumerating
> refs and walking commit history, which can be expensive in large
> repositories.
> 
> In an internal mono-repo, Trace2 showed tree unpacking finishing
> approximately 12 seconds into checkout, but the process continuing for
> roughly another 193 seconds. A stack dump captured the main thread inside
>  orphaned_commit_warning(), enumerating loose refs and opening ref files.
> Running checkout with --quiet, which bypasses this routine, reduced the
> observed runtime to approximately 14 seconds. However, --quiet also
> suppresses unrelated output.

This example shows a significant pain caused by this check, but we also
want to be able to see progress indicators over time in our logs, so
using --quiet isn't preferred, long term.

> This three-commit series adds a targeted opt-out, advertises it when the
> check is slow, and enables it in Scalar:

I did some pre-review with Wyatt (but found one nitpick in my on-list
re-review) so I'm biased. Further bias: I recommended that he follow
the model of the status.aheadBehind config [1] and advice.statusAheadBehind
[2] patches as prior art.

[1] https://lore.kernel.org/git/2f0f2a2df9410947b985d83a924d2549d62bb65f.1560889284.git.gitgitgadget@gmail.com/

[2] https://lore.kernel.org/git/c1056545b617b89e881f5991beb2fe0d860de740.1560889284.git.gitgitgadget@gmail.com/

And also I added status.aheadBehind to Scalar's recommended config in
its very first version [3]. Wyatt has updated the Scalar config docs
that justify the recommendation, which was introduced only recently [4].

[3] https://lore.kernel.org/git/4439ab4de0bc3f48a6bdcf4b5165b16fad792ebd.1638538470.git.gitgitgadget@gmail.com/

[4] https://lore.kernel.org/git/f062b0e0773b9d168c031bb1f35538665394a077.1765552528.git.gitgitgadget@gmail.com/

So I give my support publicly for Wyatt's updates.

Thanks,
-Stolee