v4.1.x: Fix handling of large data in MPI_Sendrecv_replace

[ggouaillardet]

bot:notacherrypick

[ggouaillardet]

:bot:aws:retest

[ggouaillardet]

@jsquyres could you please verify the bot?

this PR is made of two commits:

• the first one is a backport
• the second one is a straight cherry-pick

The first one contains the following messages

   (back-ported from commit 6a11873ef52191962b42ba8f56e3630e266222c7)
    bot:notacherrypick

the bot complained of a missing cherry pick message and did not notice the bot:notacherrypick directive (it even suggested me to add one !)

I would suggest to add the new bot:backport directive so we can make the distinction between backports (e.g. cherry-pick requiring manual action) and one-off commits for the release branches (because master do it differently).
A valid commit in master could even be checked when the bot:backport directive is used.

[bwbarrett]

The bot:notacherrypick goes in the PR body, not in the git commit message. We are opinionated that bot commands don’t belong in git history.

I don’t get your back port comment. The bot doesn’t check that it was a clean cherry pick or that you changed things. Only that it is either a PR marked as not a cherry commit or there’s a cherry-commit line with a reference to a valid hash.

[ggouaillardet]

Thanks @bwbarrett for the insight, I will update the PR accordingly.

Don't the bot:notacherrypick directive ends up in the merge commit (and hence git history)? (I have no intention to argue with this though)

My point is that, regardless the bot, I like to make the distinction between clean cherry pick and backports.
In the former case, the git message contains a cherry picked from commit ... line.
With the latter, after I resolve a conflict, I used to manually replace cherry picked with back-ported.

In the second case, I understand we have several options:

• leave the cherry picked from commit message: bot is happy, I am not (because I like to make it clear this is a backport and not a straightforward cherry pick)
• make a back-ported from commit message and a bot:notacherrypick message in the PR. This is stil suboptimal to me since
  • the bot does not check the back-port is from a valid commit from master
  • in the case of a PR containing multiple commits, the bot does not check the clean/straightforward commits were cherry-picked from a valid commit.
    FWIW, if this is a one off commit, I used to manually add a this is a one-off commit for the release branch
  • leave the cherry picked from commit message to keep the bot happy, and manually add a backport was required like message: in my highly subjective opinion, this does not look pretty.