GIT different merge result with different GIT versions

Question

Runnning merge command on different GIT versions we have different result:

Command is: git merge --no-ff origin/master_codeline

Results:

• Version 2.1.4 -> Merge succeded
• Version 1.7.1 -> The same merge command on the same commit return conflicts (CONFLICT (rename/add))

Now it would be easy to just update the GIT version on the OS but the 1.7.1 is the latest working version supported by our OS (Linux 2.6.34.10-0.2-xen SMP 2011-07-20 GNU/Linux, openSUSE 11.3 (x86_64) VERSION = 11.3) and we can't update the OS cause we have some constraint.

I was wondering if anyone ever experienced this kind of issues and if eventually there are way to workaround it, maybe tuning the GIT default merge options.

The conflicts output is:

CONFLICT (rename/add): Rename src/test/resources/env/env_branch2_jboss.prop->src/test/resources/env/dev2.prop in HEAD. src/test/resources/env/dev2.prop added in origin/master_codeline
Adding as src/test/resources/env/dev2.prop~origin_master_codeline instead
CONFLICT (rename/add): Rename src/test/resources/env/jboss.properties->src/test/resources/env/dev3.prop in HEAD. src/test/resources/env/dev3.prop added in origin/master_codeline
Adding as src/test/resources/env/dev3.prop~origin_master_codeline instead
Automatic merge failed; fix conflicts and then commit the result.

Unfortunately the VM where we are having these issues is our automation machine, and we run most of our merge operation on that VM.

Answer 1

You can use git status to check the detail merge conflict files. It's mainly caused some file show as deleted/added, and some file show as unmerged path.

You just need to use below commands to finish the renamed merge conflicts:

git add .
git commit

Answer 2

You should try again with a 2.31+ Git version, which default to the new ORT merge strategy.

With Git 2.36 (Q2 2022), messages "ort" merge backend prepares while dealing with conflicted paths are clearer, and differentiates inner merges and outer merges.

See commit 4a3d86e (17 Feb 2022) by Elijah Newren (newren).
^{(Merged by Junio C Hamano -- gitster -- in commit b3db182, 25 Feb 2022)}

merge-ort: make informational messages from recursive merges clearer

^{Signed-off-by: Elijah Newren}

This is another simple change with a long explanation...

merge-recursive and merge-ort are both based on the same recursive idea: if there is more than one merge base, merge the merge bases (which may require first merging the merge bases of the merges bases, etc.).
The depth of the inner merge is recorded via a variable called "call_depth", which we'll bring up again later.
Naturally, the inner merges themselves can have conflicts and various messages generated about those files.

merge-recursive immediately prints to stdout as it goes, at the risk of printing multiple conflict notices for the same path separated far apart from each other with many intervenining conflict notices for other paths between them.
And this is true even if there are no inner merges involved.
An example of this was given in this thread and apparently caused some confusion:

CONFLICT (rename/add): Rename A->B in HEAD. B added in otherbranch
...dozens of conflicts for OTHER paths...
CONFLICT (content): Merge conflicts in B

In contrast, merge-ort collects messages and stores them by path so that it can print them grouped by path.
Thus, the same case handled by merge-ort would have output of the form:

CONFLICT (rename/add): Rename A->B in HEAD. B added in otherbranch
CONFLICT (content): Merge conflicts in B
...dozens of conflicts for OTHER paths...

This is generally helpful, but does make a separate bug more problematic.
In particular, while merge-recursive might report the following for a recursive merge:

Auto-merging dir.c
Auto-merging midx.c
CONFLICT (content): Merge conflict in midx.c
to-merging diff.c
to-merging dir.c
NFLICT (content): Merge conflict in dir.c

merge-ort would instead report:

Auto-merging diff.c
Auto-merging dir.c
Auto-merging dir.c
CONFLICT (content): Merge conflict in dir.c
Auto-merging midx.c
CONFLICT (content): Merge conflict in midx.c

The fact that messages for the same file are together is probably helpful in general, but with the indentation missing for the inner merge it unfortunately serves to confuse.
This probably would lead users to wonder:

• Why is Git reporting that "dir.c" is being merged twice?
• If midx.c has conflicts, why do I not see any when I open up the file and why are no conflicts shown in the index?

Fix this output confusion by changing the output to clearly differentiate the messages for outer merges from the ones for inner merges, changing the above output from merge-ort to:

Auto-merging diff.c
  From inner merge:  Auto-merging dir.c
Auto-merging dir.c
CONFLICT (content): Merge conflict in dir.c
  From inner merge:  Auto-merging midx.c
  From inner merge:  CONFLICT (content): Merge conflict in midx.c

(Note: the number of spaces after the 'From inner merge:' is 2*call_depth).