Visualizing merge conflicts after the fact (using kdiff3)

I'm running 1.9.5.msysgit.1, but this is a general git question...

Upon returning from a vacation, I was looking at what people had been up to, and discovered on merge in which a colleague had resolved a merge incorrectly. It turns out that he has pushed *many* merges over the past year which had conflicts in my code, and now I don't trust any of them.

So naturally I want to check each of them for correctness.

I know about "git log -p -cc SHA -- path", but it really doesn't show just the conflicts so there's just too much noise in that output.

I use kdiff3 to resolve conflicts, so I'm looking for a way to visualize these already-resolved conflicts with that tool. As I said, there are many merges, so the prospect of checking out each sha, doing the merge, and then comparing the results is completely untenable.

Can anyone help? Surely other people have wanted to review how conflicts were resolved w/out looking at the noise of unconflicted changes, right?

Hi Eric,

Quoted 18 lines · Eric Raible

I'm running 1.9.5.msysgit.1, but this is a general git question...

Upon returning from a vacation, I was looking at what people had been up to, and discovered on merge in which a colleague had resolved a merge incorrectly. It turns out that he has pushed *many* merges over the past year which had conflicts in my code, and now I don't trust any of them.

So naturally I want to check each of them for correctness.

I know about "git log -p -cc SHA -- path", but it really doesn't show just the conflicts so there's just too much noise in that output.

I use kdiff3 to resolve conflicts, so I'm looking for a way to visualize these already-resolved conflicts with that tool. As I said, there are many merges, so the prospect of checking out each sha, doing the merge, and then comparing the results is completely untenable.

Quoted 3 lines

Can anyone help? Surely other people have wanted to review how conflicts were resolved w/out looking at the noise of unconflicted changes, right?

If I was walking in your shoes, I would essentially recreate the merge conflicts and then use "git diff <merge-commit>" with the resolved merge in your current history.

Something like this:

```bash
mergecommit=$1

# probably should verify that the working directory is clean, yadda yadda

# recreate merge conflicts on an unnamed branch (Git speak: detached HEAD)
git checkout $mergecommit^
git merge $mergecommit^2 ||
die "This merge did not have any problem!"

# compare to the actual resolution as per the merge commit
git diff $mergecommit
```

To list all the merge commits in the current branch, I would use the command-line:

```bash
git rev-list --author="My Colleague" --parents HEAD |
sed -n 's/ .* .*//p'
```

(i.e. listing all the commits with their parents, then filtering just the ones having more than one parent, which would include octopus merges if your history has them.)

Hopefully this gives you good ideas how to proceed.

Ciao,
Johannes
.

Hi Eric,

Quoted 18 lines · Eric Raible

I'm running 1.9.5.msysgit.1, but this is a general git question...

Upon returning from a vacation, I was looking at what people had been up to, and discovered on merge in which a colleague had resolved a merge incorrectly. It turns out that he has pushed *many* merges over the past year which had conflicts in my code, and now I don't trust any of them.

So naturally I want to check each of them for correctness.

I know about "git log -p -cc SHA -- path", but it really doesn't show just the conflicts so there's just too much noise in that output.

I use kdiff3 to resolve conflicts, so I'm looking for a way to visualize these already-resolved conflicts with that tool. As I said, there are many merges, so the prospect of checking out each sha, doing the merge, and then comparing the results is completely untenable.

Quoted 3 lines

Can anyone help? Surely other people have wanted to review how conflicts were resolved w/out looking at the noise of unconflicted changes, right?

If I was walking in your shoes, I would essentially recreate the merge conflicts and then use "git diff <merge-commit>" with the resolved merge in your current history.

Something like this:

```bash
mergecommit=$1

# probably should verify that the working directory is clean, yadda yadda

# recreate merge conflicts on an unnamed branch (Git speak: detached HEAD)
git checkout $mergecommit^
git merge $mergecommit^2 ||
die "This merge did not have any problem!"

# compare to the actual resolution as per the merge commit
git diff $mergecommit
```

To list all the merge commits in the current branch, I would use the command-line:

```bash
git rev-list --author="My Colleague" --parents HEAD |
sed -n 's/ .* .*//p'
```

(i.e. listing all the commits with their parents, then filtering just the ones having more than one parent, which would include octopus merges if your history has them.)

Hopefully this gives you good ideas how to proceed.

Ciao,
Johannes

Johannes Schindelin venit, vidit, dixit 16.06.2015 11:43:

Quoted 7 lines

To list all the merge commits in the current branch, I would use the command-line:

```bash
git rev-list --author="My Colleague" --parents HEAD |
sed -n 's/ .* .*//p'
```

Quoted 1 line

(i.e. listing all the commits with their parents, then filtering just the ones having more than one parent, which would include octopus merges if your history has them.)

:)

"--merges" (aka "--min-parents=2") is your friend here.

This type of request comes up often (for a reason). I'm wondering whether we could support it more systematically, either by exposing the steps above as a command, or by storing the unresolved merge somewhere (leveraging stash or rerere).

Quoted 4 lines · Michael J Gruber

This type of request comes up often (for a reason). I'm wondering whether we could support it more systematically, either by exposing the steps above as a command, or by storing the unresolved merge somewhere (leveraging stash or rerere).

Perhaps 'tr/remerge-diff' (on 'pu') is of interest?

Junio C Hamano venit, vidit, dixit 18.06.2015 17:57:

Quoted 2 lines

Perhaps 'tr/remerge-diff' (on 'pu') is of interest?

I haven't reviewed remerge-diff but merged it on top of my own local additions and ran the full test suite successfully. Any big blocker to watch out for?

So naturally I want to check each of them for correctness.