mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: Elijah Newren <>
To: "Middelschulte, Leif" <>
Cc: "" <>
Subject: Re: git merge banch w/ different submodule revision
Date: Thu, 26 Apr 2018 17:19:20 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Thu, Apr 26, 2018 at 3:49 AM, Middelschulte, Leif
<> wrote:
> Hi,
> we're using git-flow as a basic development workflow. However, doing so revealed unexpected merge-behavior by git.
> Assume the following setup:
> - Repository `S` is sourced by repository `p` as submodule `s`
> - Repository `p` has two branches: `feature_x` and `develop`
> - The revisions sourced via the submodule have a linear history
> * 1c1d38f (feature_x) update submodule revision to b17e9d9
> | * 3290e69 (HEAD -> develop) update submodule revision to 0598394
> |/
> * cd5e1a5 initial submodule revision
> Problem case: Merge either branch into the other
> Expected behavior: Merge conflict.
> Actual behavior: Auto merge without conflicts.
> Note 1: A merge conflict does occur, if the sourced revisions do *not* have a linear history
> Did I get something wrong about how git resolves merges? Shouldn't git be like: "hey, you're trying to merge two different contents for the same line" (the submodule's revision)

Hard to say without saying what commit was referenced for the
submodule in the merge-bases for the two repositories you have.  In
the basic case..

If branch A and branch B have different commits checked out in the
submodule, say:
   A: deadbeef
   B: ba5eba11

then it's not clear whether there's a conflict or not.  The merge-base
(the common point of history) matters.  So, for example if the
original version (which I'll refer to as 'O") had:
  O: deadbeef

then you would say, "Oh, branch A made no change to this submodule but
B did.  So let's go with what B has."  Conversely, of O had ba5eba11,
then you'd go the other way.

But, there is some further smarts in that if either A or B point at
commits that contain the other in their history and both contain the
commit that O points at, then you can just do a fast-forward update to
the newest.

You didn't tell us how the merge-base (cd5e1a5 from the diagram you
gave) differed in your example here between the two repositories.  In
fact, the non-linear case could have several merge-bases, in which
case they all become potentially relevant (as does their merge-bases
since at that point you'll trigger the recursive portion of
merge-recursive).  Giving us that info might help us point out what
happened, though if either the fast-forward logic comes into play or
the recursive logic gets in the mix, then we may need you to provide a
testcase (or access to the repo in question) in order to explain it
and/or determine if you've found a bug.

Does that help?


  parent reply	other threads:[~2018-04-27  0:19 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-26 10:49 git merge banch w/ different submodule revision Middelschulte, Leif
2018-04-26 17:56 ` Stefan Beller
2018-04-26 21:46   ` Jacob Keller
2018-04-26 22:19     ` Stefan Beller
2018-04-30 17:02       ` Heiko Voigt
2018-05-02  7:30         ` Middelschulte, Leif
2018-05-03 16:42           ` Heiko Voigt
2018-05-04  8:29             ` Middelschulte, Leif
2018-05-04 10:18               ` Heiko Voigt
2018-05-04 14:43                 ` Elijah Newren
2018-05-07 14:23                   ` Middelschulte, Leif
2018-04-27  0:02     ` Elijah Newren
2018-04-27  0:19 ` Elijah Newren [this message]
2018-04-27 10:37   ` Middelschulte, Leif
2018-04-28  0:24     ` Elijah Newren
2018-04-28  7:22       ` Jacob Keller

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:

  List information:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \

* 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.
Code repositories for project(s) associated with this public inbox

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 read-only IMAP folder(s) and NNTP newsgroup(s).