Re: [PATCH v7 4/4] branch: let --delete-integrated find branches merged onto changed files

[Tuomas Ahola <taahol@utu.fi>]

"Harald Nordgren via GitGitGadget" <gitgitgadget@gmail.com> wrote:

> From: Harald Nordgren <haraldnordgren@gmail.com>
> 
> A branch that upstream integrated with
> 
>     git merge --squash topic
>     git commit
> 
> after upstream had also changed the files the branch touches is still
> kept by "git branch --delete-integrated". The squash commit has neither
> the branch's version of those files nor the fork point's, so the
> previous check cannot see that the work landed. This happens all the
> time on hosting services, where the "Squash and merge" button on GitHub

Nit: that sentence scans a bit awkwardly.  Perhaps something along these
lines would make the idea more clear?

	This happens all the time on hosting services such as GitHub,
	where the "Squash and merge" button lands...

> lands pull requests this way while the main branch keeps moving. A

Hmm, I'm not sure if I understood that.  What is "while the main branch
keeps moving" trying to say?

> rebase merge onto such changes looks the same.
> 
> For each such file, merge the branch's version into the upstream one
> and treat the change as landed when that leaves the upstream version
> unchanged. This has to read the files, so in a partial clone it may
> download blobs.
> 
> The merge uses the attributes of this repository, from the working tree
> and the index, the same as a merge run here would. A merge driver that
> only the upstream repository has is not seen. In a bare repository only
> info/attributes and the global file apply.
> 
> Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com>
> ---
>  Documentation/git-branch.adoc | 13 +++--
>  builtin/branch.c              | 72 ++++++++++++++++++++++----
>  t/t3200-branch.sh             | 95 +++++++++++++++++++++++++++++++++++
>  3 files changed, 165 insertions(+), 15 deletions(-)
> 
> diff --git a/Documentation/git-branch.adoc b/Documentation/git-branch.adoc
> index 6be28c8a4e..489a9d5fd0 100644
> --- a/Documentation/git-branch.adoc
> +++ b/Documentation/git-branch.adoc
> @@ -240,11 +240,14 @@ remove it anyway.
>  	Like `--delete-merged`, but also delete a branch whose changes
>  	the upstream already has even though its commits are not there,
>  	as happens after a squash or rebase merge. Such a branch is
> -	deleted when some upstream commit since the fork point has its
> -	version of every file it changed, even if those changes were
> -	later reverted, and the message names the first such commit.
> -	It does not matter who made that commit. The same rules for
> -	which branches are kept apply as for `--delete-merged`.
> +	deleted when some upstream commit since the fork point has all
> +	of its changes, even if they were later reverted, and the
> +	message names the first such commit. It does not matter who made
> +	that commit. A file counts when the commit has the branch's
> +	version of it, or when merging the branch's version into the
> +	commit's leaves it unchanged, which reads the file and may

Err, what exactly is the antedecent of that "which"?  (Okay, I think the answer
is "merging", but I had to read the sentence again and again before I saw that.
Can we make the passage a little easier to grasp?)

> +	download blobs in a partial clone. The same rules for which
> +	branches are kept apply as for `--delete-merged`.
>  
>  `--dry-run`::
>  	With `--delete-merged` or `--delete-integrated`, print which
> diff --git a/builtin/branch.c b/builtin/branch.c