From: Jonathan Nieder <jrnieder@gmail.com>
To: Mihail Atanassov <m.atanassov92@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH] Documentation/git-bisect.txt: add --no-ff to merge command
Date: Fri, 25 Oct 2019 19:26:55 -0700 [thread overview]
Message-ID: <20191026022655.GF39574@google.com> (raw)
In-Reply-To: <20191025222032.3399-1-m.atanassov92@gmail.com>
Hi,
Mihail Atanassov wrote:
> The hotfix application example uses `git merge --no-commit` to apply
> temporary changes to the working tree during a bisect operation. In some
> situations this can be a fast-forward and `merge` will apply the hotfix
> branch's commits regardless of `--no-commit` (as documented in the `git
> merge` manual).
>
> In the pathological case this will make a `git bisect
> run` invocation to loop indefinitely between the first bisect step and
> the fast-forwarded post-merge HEAD.
>
> Add `--no-ff` to the merge command to avoid this issue, and make a note
> of it for the reader.
>
> Signed-off-by: Mihail Atanassov <m.atanassov92@gmail.com>
> ---
> Documentation/git-bisect.txt | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
Good catch. Thanks for fixing it.
> diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
> index 4b45d837a7..58b5585874 100644
> --- a/Documentation/git-bisect.txt
> +++ b/Documentation/git-bisect.txt
> @@ -412,8 +412,10 @@ $ cat ~/test.sh
> #!/bin/sh
>
> # tweak the working tree by merging the hot-fix branch
> -# and then attempt a build
> +# and then attempt a build. Note the `--no-ff`: `git merge`
> +# will otherwise still apply commits if the current HEAD can be
> +# fast-forwarded to the hot-fix branch.
Hmm. I think the comment might put a bit too much emphasis on the
"how" instead of the "why". Is it necessary to describe why --no-ff
is used at all here? After all, a reader wondering about it is likely
to check "git help merge", which says
Fast-forward updates do not create a merge commit and
therefore there is no way to stop those merges with
--no-commit. Thus, if you want to ensure your branch is not
changed or updated by the merge command, use --no-ff with
--no-commit.
So I'd be tempted to leave the comment ending with "and then attempt a
build".
Alternatively: the wording says "will still apply commits", but the
reader might not think of a merge as applying patches (that's closer
to what cherry-pick does. Is there some alternative wording that
would convey the intent more clearly?
> -if git merge --no-commit hot-fix &&
> +if git merge --no-commit --no-ff hot-fix &&
Good.
Thanks and hope that helps,
Jonathan
next prev parent reply other threads:[~2019-10-26 2:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-25 22:20 [PATCH] Documentation/git-bisect.txt: add --no-ff to merge command Mihail Atanassov
2019-10-26 2:26 ` Jonathan Nieder [this message]
[not found] ` <CALs020+0E=7wy-N46BRLrBcKmMSTpcMyZ9WybmgTzb60aCo5PQ@mail.gmail.com>
2019-10-28 22:10 ` Mihail Atanassov
2019-10-28 22:24 ` Jonathan Nieder
2019-10-29 2:24 ` Junio C Hamano
2019-10-29 3:25 ` Junio C Hamano
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191026022655.GF39574@google.com \
--to=jrnieder@gmail.com \
--cc=git@vger.kernel.org \
--cc=m.atanassov92@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).